Chemistry in Pictures Winner Lycopodium powder Susan Yochum from Seton Hill University, Greensburg PA sent in photographic proof of the effects of surface area on a combustion reaction. The dramatic result of spraying lycopodium powder through the flame of a candle is captured in the photo! Lycopodium powder is a fine yellow powder made from the spores of the lycopodium plant which is a small pine that grows low to the ground. The powder is commercially available from various chemical or science education supply vendors at a reasonable cost. Luckily the plant grows in the woods of western Pennsylvania so Susan can bring in a sample to show her students. Susan noted that if one places a small amount of the powder on the end of a spatula and holds it in the flame, the lycopodium does not ignite. However, when the powder is sprayed through the flame, the powder ignites producing a tremendous flame due to the increased surface area. Students agree that this is an enlightening demo that enhances their understanding of the impact of concentration and surface area on reaction rates. Observers should stand at least 10 feet from the demonstration and wear safely goggles. The teacher should follow all safety considerations when working with a combustion reaction in class. ∎ May 2014 Number 407 on reaction rates . O bservers should stand at least 10 feet from the demonstratio n and wear safely goggles . The teacher should follow all safety considerations when working with a combustion reaction in class . ∎ May 2014 Number 407 Chemistry in Pictures Winner Lycopodium powder Chemistry in Pictures Winner Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1 | www.uwaterloo.ca /chem13news
Transcript
May 2014 Number 407
Chemistry in Pictures Winner Lycopodium powder
Susan Yochum from Seton Hill University, Greensburg PA sent in photographic proof of the effects of surface area on a combustion reaction. The dramatic result of spraying lycopodium powder through the flame of a candle is captured in the photo! Lycopodium powder is a fine yellow powder made from the spores of the lycopodium plant which is a small pine that grows low to the ground. The powder is commercially available from various chemical or science education supply vendors at a reasonable cost. Luckily the plant grows in the woods of western Pennsylvania so Susan can bring in a sample to show her students. Susan noted that if one places a small amount of the powder on the end of a spatula and holds it in the flame, the lycopodium does not ignite. However, when the powder is sprayed through the flame, the powder ignites producing a tremendous flame due to the increased surface area. Students agree that this is an enlightening demo that enhances their understanding of the impact of concentration and surface area on reaction rates. Observers should stand at least 10 feet from the demonstration and wear safely goggles. The teacher should follow all safety considerations when working with a combustion reaction in class. ∎
May 2014 Number 407
Chemistry in Pictures Winner Lycopodium powder
Susan Yochum from Seton Hill University, Greensburg PA sent in photographic proof of the effects of surface area on a combustion reaction. The dramatic result of spraying lycopodium powder through the flame of a candle is captured in the photo! Lycopodium powder is a fine yellow powder made from the spores of the lycopodium plant which is a small pine that grows low to the ground. The powder is commercially available from various chemical or science education supply vendors at a reasonable cost. Luckily the plant grows in the woods of western Pennsylvania so Susan can bring in a sample to show her students. Susan noted that if one places a small amount of the powder on the end of a spatula and holds it in the flame, the lycopodium does not ignite. However, when the powder is sprayed through the flame, the powder ignites producing a tremendous flame due to the increased surface area. Students agree that this is an enlightening demo that enhances their understanding of the impact of concentration and surface area on reaction rates. Observers should stand at least 10 feet from the demonstration and wear safely goggles. The teacher should follow all safety considerations when working with a combustion reaction in class. ∎
on reaction rates.
Observers should stand at least 10 feet from the demonstration and wear safely goggles. The teacher should follow all safety considerations when working with a combustion reaction in class. ∎
May 2014 Number 407
Chemistry in Pictures WinnerLycopodium powder
EDITOR
Jean Hein
EDITORIAL BOARD
L.J. Brubacher
J.M. Chong
M.P. Jansen
A. R. Ricci
S. Willfang
PRODUCTION
Kathy Jackson
Chemistry in Pictures WinnerDepartment of Chemistry, University of Waterloo,Waterloo, Ontario, Canada N2L 3G1 | www.uwaterloo.ca/chem13news
2 Chem 13 News/May 2014
What is in this issue?
Letters to the editor, page 3 Element roulette challenge, page 4 Sharing…it goes beyond kindergarten, page 5 Phasing out the demo, page 5 An absent-minded prof’s crostic, pages 6 and 7 Taking the poisonous bite out of cyanide and avoiding other poisons, page 8 ICCE 2014, page 9 An all-natural banana, pages 10 and 11 BCCE 2014, page 12 What we can teach with hybrid orbitals,
pages 13-15 A snapshot of summer chemical education
conferences, pages 16 and 17 Chem Dates, page 18
Publishing Chem 13 News
Chem 13 News is published for teachers by the Department of
Chemistry, University of Waterloo, Waterloo, Ontario, Canada. The editors welcome letters, ideas and articles helpful to other teachers. (For author’s guidelines go to: http://www.uwaterloo.ca/chem13news)
Opinions expressed are those of our authors. We recommend professional caution in adopting other people’s experiments and demonstrations.
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Mailing address: Chem 13 News, Department of Chemistry, University of Waterloo, Waterloo ON N2L 3G1. Tel: 519-888-4567, ext 32505. Fax: 519-888-9168. E-mail: [email protected].
This issue was prepared by Jean Hein, editor; Kathy Jackson, production; Sushant Bhasin, Lew Brubacher, David Cash, Mike Chong, Jenn Coggan, Brian Ellis, Kaitlan Huckabone, Susan Kelso, Sue Stathopulos, Kaitlin Town and Stacey Willfang, proofreading; and Simpson Screen Print and Lithography Ltd., Bloomingdale ON.
**Credit card charges will be in Canadian dollars. The exchange rate is applied at time of processing.
Periodic Table Project Fl and Lv winners Last fall the winners of the tile designs for the newly named elements were announced. Aside from having their tiles on the Periodic Table Project iPod and iPad app, the students received a plaque of their winning tile. The plaques were presented by their respective chemistry teachers.
Sarah Cescon from the University of Toronto Schools presents Emily Lam (right) with a plaque of her winning flerovium tile.
Jeff Greenslade at Campbell Collegiate, Regina SK presents Lisa Lai (left) with a plaque of her winning livermorium tile.
Want to see the new elemental tiles and read about their design? The most up-to-date Periodic Table is available on iTunes. All the creative tiles for each element along with elemental data can be found on the free-to-download Periodic Table Project app. This app will inspire your students to delve into the wonders of the elements.
Search Periodic Table Project on iTunes. ∎
May 2014/Chem 13 News 3
Letters to the editor ∙ The use of the demonstration “A Colorful Catalyst” by Meridith Rahman and Kenneth Lyle, Chem 13 News, March 2014 (pages 12 and 13) provides a great opportunity for a problem-solving moment with your class.
David Katz* taught me this demo many years ago, and I have used it in my classroom for at least 25 years. After doing the demonstration, ask the class the following questions.
“What is the actual catalyst: the cobalt ions, the chloride ions or the combination of these ions?
How can we find out?
What changes can be made to the demonstration to make that determination?”
Let the students think about it and design a method to test for the actual catalyst.
[To remind readers: A pink-coloured solution of cobalt(II) chloride (the catalyst) is added to a warm mixture of sodium potassium tartrate and hydrogen peroxide (the reaction mixture). After some colour changes, the pink colour returns once the reaction goes to completion.]
A good method would be to repeat the experiment isolating the suspected catalyst ions.
1) Repeat by adding 0.15 M sodium chloride or potassium chloride to the reaction mixture. Ask students “Why not add calcium chloride?” Point out that no calcium ions are involved in the original demo.
2) Ask students how to test if the cobalt(II) ion is the catalyst. What compound could be added to the reaction mixture? Then add 0.15 M cobalt(II) tartrate which insures no new extraneous ions are introduced.
If chloride ions increase the reaction rate as in the original demo, then chloride ions act as the catalyst. If the cobalt(II) tartrate increases the reaction, then the catalyst is the cobalt(II) ions. If neither reaction above (1) or (2) increases the original demonstration reaction, then cobalt(II) chloride is the catalyst.
Due to the colour changes students will probably guess correctly that the catalyst is cobalt(II) ions. This gives experimental proof and allows for some scientific exploration.
Cobalt(II) tartrate is available from Alfa Aesar [Johnson-Mathey] chemicals, or you can make some by mixing cobalt chloride with sodium potassium tartrate.
*Note: David Katz has been generating ideas for the chemistry classroom since the 1970s and maintains a website with a variety of labs and activities: www.Chymist.com
∙ I enjoyed Meridith Rahman and Kenneth Lyle's piece in the March issue of Chem 13 News. They explained the interesting, colourful, Co2+ ion-catalyzed oxidation of tartrate ions by hydrogen peroxide in aqueous solution. One can get a lot of mileage out of this demonstration, catalyst-wise and reaction intermediate-wise. The Royal Society of Chemistry1 suggests the removal — use a large, plastic Beral pipet — of several mL of the green reaction intermediate, with immediate transfer to a test tube sitting in salt/ice water bath. This slows the decomposition of the intermediate to the point where the green colour sticks around for well over an hour. This facilitates discussion of the temperature dependence of reaction rates, and on freezing point depression. Note: 1. http://www.rsc.org/Education/EiC/issues/2005July/
Exhibitionchemistry.asp Michael P. Jansen <[email protected]> Crescent School, Toronto ON ∎ A strange factoid about a zinc supplement David Cash <[email protected]> Mohawk College (Retired) Seeking to calculate the percent by mass of the active ingredient in a tablet of zinc mineral supplement, an interesting fact was discovered. The zinc supplement is manufactured by Jamieson Laboratories of Toronto; the label amount is 10 mg zinc.1 These supplement tablets are utilized as analytical samples in an EDTA titration laboratory exercise for an introductory analytical chemistry course at Mohawk College.2 The zinc in the tablets is in the form of zinc gluconate. Wikipedia was consulted for the structure and molar mass of gluconic acid and hence of the gluconate anion.3 The article in Wikipedia is short, but an interesting statement and link caught my attention. A solution of zinc gluconate can be used by injection to necrotize the testicles of male dogs, rendering them neutered!!4
2. Experiments for term 2 of the 2-year programs for health science, environmental, and biotechnology technicians: http://www.uclmail.net/users/dn.cash/experiments.html.
4. American Journal of Veterinary Research 2008: http://avmajournals.avma.org/doi/abs/10.2460/ajvr.69.1.140. ∎
4 Chem 13 News/May 2014
Element roulette challenge Part 1: Complete the set Each of the roulette wheels below has an element missing which will complete the set. First try the sample wheel on the right. The answer is at the bottom to ensure you are on right track. After you do the sample, you can begin to find the missing elements. Note: no element is repeated in a wheel.
Part 2: Complete the pattern The wheels below are missing elements which will complete a pattern. First try the sample wheel to the right. The answer is below. Then find the missing elements. Note: no element is repeated in a wheel
Enter your students’ correct solutions into a draw on or before June 30, 2014. The book prize is Expose, Excite, Ignite (see page 19) and is donated by Educational Innovations. The prize will be for both student and teacher. Go to www.teachersource.com for more about this prize. Send your students’ solutions to: Chem 13 News, Element roulette challenge, Department of Chemistry, University of Waterloo, Waterloo ON N2L 3G1, Canada; Fax: 519-888-9168; or email: [email protected]. ∎
Answers to sample problems
Part 1: Prime numbers from 1 to 11 are part of the set with the missing number 7. Part 2: The opposite facing sections equal 14 so the missing number is 10. Hint: You may need your solubility tables for one of the wheels.
May 2014/Chem 13 News 5
Sharing… goes beyond kindergarten Michael P. Jansen <[email protected]> Crescent School, Toronto ON I heard more than once that some chemistry teachers don’t like to share. I’m not referring to popsicles or spouses, but to self-developed resources: handouts, labs, PowerPoint lessons and the like. Why would teachers hoard resources? It boggles the mind. A teacher works hard to produce a high quality item. Must that piece of excellence die with him or her? Can no one take this resource and improve it or put his or her spin on it? Could the reason be financial? It makes no sense: How much money can one make from a kinetics lab or a stoichiometry worksheet? Bill Gates didn’t get rich from his review sheets. Maybe the reason is more like “Why should I share with Mr. So-and-so? He’s lazy.” Okay, fine, but do his students need to suffer? It sounds like they’re suffering enough.
Perhaps teachers don’t like to share their resources because they don’t think they’ll get the credit they deserve. “This is my [whatever]… and I want everyone to know it.” Forget about credit — think about karma. If you’re a teacher who doesn’t share, GET OVER IT. It is not about you, and it’s not about your students. It’s about students. If you’re in a department that does not value this kind of collegiality, be the change you want to see. And if you’re a teacher who shares the fruits of his or her labour — in Chem 13 News or at conferences or in the staff room — I’m preaching to the converted. (In any case, the editor suggested that I ask you to post this by the photocopier or the coffee machine.)
Phasing out the demo Sharon Geyer <Sharon Geyer <[email protected]> Pomfret School, Pomfret CT I’m struggling to make peace with phasing out class demonstrations. I am in the middle of the transition from a traditional classroom into a student-centered learning environment. This summer at ChemEd 2013 I realized that the quest for the perfect chemistry demo is outdated pedagogy that pays homage to the “Sage on the Stage” model of teaching. I wrote in my first blog post (http://artofteachingscience.blogspot.ca), Dr. Shakhashiri opened my eyes to the wonderful world of chemistry demonstrations. Adding class demos to my lessons literally saved my teaching career in my second year. I dedicated the first year of this blog to documenting how I implemented new class demos. Researching demos and learning new chemistry was very exciting for me as I wrote my first series of blog posts. Yet, now I feel frustrated by the class demo because my students are passively watching me “do science” for them. Last week I spent a class period doing a series of demos as part of my chemical reactions unit. After a week in which my kids explored chemical reactions in the lab, I followed up with some “more exciting” reactions as a way of reviewing their understanding of predicting products and writing chemical equations. (I presented on this topic at ChemEd 2013 in Waterloo. My fellow chemistry teachers were excited by the lesson and my handouts are posted at ChemEd 2013 site.) The class was going along as planned, my students were sitting around a central lab table, white boards and markers in hand. After every demo I performed, they wrote out the chemical reaction to describe what they saw. The eye-opening moment for me was the big finale; I ended the day with my “thermite two ways” demo. I took the class outside to watch the famous
thermite reaction. The flying sparks and the dripping molten iron created plenty of “oohhs” and “aahhhs” as students watched the awesome power of the thermite. Then, I got out my rusty cannonballs* (one wrapped in aluminum foil) and showed them “hand held” thermite.* Banging the two cannonballs together produces a loud pop and sparks. After I got a good pop and some sparks, I passed the cannonballs to a student. That’s when the magic happened. My students got so energized by watching their classmates create the hand-held thermite reaction. Each successful bang was greeted with cheers and applause. One boy was crowned the thermite master; he forced some amazing blasts out of those two cannonballs. I walked away from this day smiling at the great enthusiasm the kids had during class. But, later that day, as I started reflecting on the lesson, it hit me like a ton of bricks: it only got exciting when the chemistry was in the students’ hands. I was reminded once again that learning happens when the students engage in the process. The flipped classroom has changed everything for me. When I moved myself from the center of the stage, my goal shifted away from teaching the perfect lesson and toward creating an engaging learning environment. I realized that kids don’t learn by watching me blow up things and light stuff on fire. Yes, I know it’s really fun for everyone, especially me, to do a big “ta-da” demo. I am the first to admit that I love demos. Yet, when I put learning as the central objective in my class, rather than performing, the outcome is unpredictable, rich and sometimes magical. *Note: Find “Thermite reaction with rusty iron balls” at the Chem 13 News website (under May Supplemental Materials). ∎
6 Chem 13 News/May 2014
An absent-minded prof’s crostic Gerry Toogood, Department of Chemistry University of Waterloo, Waterloo ON We’ll send a book prize to the person whose name we draw from among those who submit the correct solution (including the clue answers) to this puzzle on or before October 1, 2014. Fax: 519-888-9168. E-mail: [email protected]. Post: Chem 13 News, An absent-minded prof’s crostic, Department of Chemistry, University of Waterloo, Waterloo ON N2L 3G1, Canada. Start by answering as many clues as possible. (Even if you can answer only a quarter of the clues, your chances of completing the crostic are very good.) Semi-colons in some clues are used to separate alternative clues for the same answer. Next, transfer these letters to the correspondingly numbered squares in the grid. This begins the spelling out of the quotation, reading from left to right, with black squares separating the words. (Words may spill over to the next row; punctuation marks are not included.) As you proceed, words and phrases begin forming in
the quotation; working back and forth between the grid and the clue words, you can complete the puzzle. To aid you further, note that the first letters of the clue answers spell out the source of the quotation. Three letters are given, in answers H, O and AA. Clues (numbers in parentheses indicate number of words) A A scheme named after – two Germans who 5 373 233 364 9 175 53 27 30
independently devised this method of calculating 89 372 113 43 353 lattice energies etc. (2) B Shoppers “D” hour (anag); elemental 349 6 180
form (2) 29 41 15 19 331 376 254 55 60 98
1 EE 2 C
1
7
9
9 3 F 4 FF 5 A 6 B 7 J 8 HH 9 A 10 FF 11 EE 12 HH 13 D 14 GG 15 B 16 F
17 AA 18 U 19 B 20 V 21 J 22 O 23 C 24 GG 25 F 26 FF 27 A 28 X 29 B 30 A 31 F 32 FF 33 C 34 G 35 I 36 I 37 G
38 K 39 Y 40 C 41 B 42 GG 43 A 44 M 45 S 46 O 47 P 48 D 49 AA 50 W 51 FF 52 U 53 A 54 D 55 B 56 Z 57 F 58 I
59 I 60 B 61 D 62 DD 63 N 64 J 65 G 66 E 67 CC 68 FF 69 BB 70 Y 71 DD 72 AA 73 E 74 G 75 F 76 Z 77 GG 78 F
79 AA 80 BB 81 HH 82 E 83 DD 84 J 85 AA 86 Y 87 X 88 M 89 A 90 M 91 V 92 O 93 AA 94 K 95 BB 96 Y 97 DD
98 B 99 BB 100 X 101 CC 102 N 103 AA 104 Q 105 Y 106 E 107 K 108 X 109 Q 110 V 111 K 112 E 113 A 114 M 115 R 116 Z 117 O
118 HH 119 K 120 X 121 S 122 K 123 N 124 L 125 V 126 T 127 M 128 Y 129 F 130 C 131 Q 132 V 133 Y 134 X 135 D 136 V 137 R 138 J
139 M 140 FF 141 N 142 O 143 Z 144 M 145 G 146 GG 147 Q 148 N 149 N 150 S 151 AA 152 R 153 K 154 N 155 Q 156 Q 157 G
158 CC 159 W 160 K 161 O 162 K 163 S 164 N 165 U 166 V 167 R 168 K 169 U 170 R 171 Q 172 X 173 N 174 P 175 A
176 AA 177 H 178 D 179 X 180 B 181 Q 182 X 183 DD 184 Q 185 O 186 N 187 Y 188 AA 189 C 190 S 191 U 192 Y 193 H 194 O 195 S
196 V 197 H 198 T 199 BB 200 AA 201 K 202 O 203 DD 204 Q 205 H 206 Q 207 BB 208 CC 209 HH 210 O 211 R 212 U 213 H 214 S 215 AA
216 EE 217 DD 218 Q 219 L 220 L 221 N 222 M 223 C 224 V 225 S 226 Q 227 X 228 K 229 Z 230 V 231 DD 232 N 233 A 234 HH 235 CC 236 O
237 H 238 M 239 N 240 BB 241 U 242 H 243 BB 244 Y 245 HH 246 H 247 AA 248 C 249 EE 250 CC 251 I 252 U 253 Y 254 B 255 HH 256 H
257 Y 258 GG 259 BB 260 HH 261 I 262 H 18
263 M 264 HH 265 H 266 GG 267 AA 268 Y 269 F 270 Q 271 M 272 P 273 DD 274 I 275 GG
276 I 277 D 278 CC 279 DD 280 Z 281 H 282 M 283 C 284 I 285 AA 286 HH 287 L 288 P 289 J 290 K 291 Z 292 X 293 J 294 FF 295 K
296 AA 297 C 298 GG 299 BB 300 CC 301 BB 302 DD 303 I 304 BB 305 U 306 X 307 L 308 CC 309 S 310 DD 311 I 312 Q 313 X 314 I
315 FF 316 E 317 M 318 AA 319 O 320 CC 321 J 322 EE 323 AA 324 K 325 DD 326 R 327 CC 328 T 329 N 330 GG 331 B 332 EE 333 O 334 D 335 FF
336 I 337 G 338 DD 339 G 340 HH 341 G 342 DD 343 N 344 E 345 R 346 O 347 N 348 GG 349 B 350 D 351 EE 352 T 353 A 354 O 355 AA
356 GG 357 S 358 K 359 GG 360 C 361 G 362 I 363 C 364 A 365 W 366 DD 367 Z 368 Q 369 HH 370 AA 371 D 372 A 373 A 374 C 375 Y
376 B 377 FF 378 E
May 2014/Chem 13 News 7
C Titrations with a certain – hexadentate ligand 33 189 223 283 363 2 248
involve them (2) 40 23 297 374 360 130
D The λ in c = λ 334 277 135 54 13 371 61 178 350 48
E Entangled (1 possible spelling) 82 344 378 106 66 73 112 316
F (With ans. G), e.g., 3 57 75 31 16 269 25 129 78
and G See clue F
157 339 37 145 337 341 361 65 74 34
H Impatient doorknock R – – – 177 213 193 246 237 256 – 205 242 197 262 265 281
I That of the metal in answers EE and BB is 36 261 311 362 303 251 336 274 59
nine (2) 35 276 314 284 58
J Carbon allotrope 138 7 321 21 84 293 289 64
K Not a good place to be for hunters of antlers 153 324 295 290 94 107 38 119
(4) 122 111 162 358 160 168 228 201
L TV equivalents of Oscars 124 287 307 219 220
M The study of quant. – relationships governing 238 127 44 222
the comp. of substances and their reactions 317 114 271 90 282 144 139 88 263
N What Americas Cup fans want to get (4) 63 232 149 221 329 102 347
141 123 343 173 164 186 148 154 239
O (CH3)2CH-OH (2) I 346 46 319 117 354 22 333 92
142 236 194 210 161 185 202
P Word before black, lighter or post 272 288 174 47
Q Medication to control manic depression (2) 312 226 147 171 155 206 270
Taking the poisonous bite out of cyanide and avoiding other poisons Enrico Uva <[email protected]> Laurenhill Academy, St. Laurent QC Unless you’re a falsely accused, innocent bystander at the scene of a crime, coincidences can be fun in life. I was demonstrating the reduction of permanganate ion (MnO4-) by thiosulfate ion (S2O32-) to my students. As the purple permanganate solution removes electrons from the thiosulfate, the brown product MnO2 appears. It can be more dramatic if HSO3
- is used because the reaction products go completely colourless, but if bisulfite is not available, as was the case in our school, acidified MnO4
- will also do the trick with thiosulfate. On the same day, in a little black notebook1 that I use to keep track of various science tidbits, I came across the strange story of the eastern tent caterpillar, and I decided to share that story with my class. The caterpillars concentrate cyanoglucosides (specifically prunasin) from the leaves of wild cherry that they devour.
Prunasin (notice the cyano group)2 Enzymes then convert the compounds to cyanide, which the caterpillar spits out at its potential predators. Other defensive compounds such as acetone and benzaldehyde are also included in their saliva. Of course, it begs the question, how does such a caterpillar prevent poisoning itself? This is where rhodanese — an enzyme found in the mitochondria of many animals — comes in. This enzyme can convert cyanide (CN-) to thiocyanate (SCN-), which is much less toxic. Most animals are susceptible to cyanide poisoning because the rhodanese is not distributed in the mitochondria of all tissues. This is probably not the case with caterpillars. But where does the coincidence enter the picture? It is the question of where rhodanese gets the sulfur to attach to the cyanide group: from thiosulfate, the same ion (in solution) sitting on our demonstration desk. In other words, the thiosulfate that reduces the permanganate in our demonstration, participates in this reaction to convert cyanide to thiocyanate, hence saving this caterpillar from a toxic fate. Then the following day there was another connection to the demonstration in the news. The Ottawa Citizen reported that paramedics had to treat 11 students at the Higher Learning
Institute for chlorine poisoning. They had acidified potassium permanganate with hydrochloric acid. This was done either deliberately or accidentally, but in either case, the chloride ion was oxidized to chlorine gas by the stronger oxidizing agent, MnO4
-. We had kept our demo safe by acidifying the electron-mugger with vinegar. Sulfuric acid would also have been a safe alternative. Students were awed by another coincidence, and by the fact that in chemistry there’s a fine line between a successful demo and a disaster. Notes and references 1. Enrico’s black notebook
[We decided to show this page of equations to highlight how Enrico collects these tidbits in this book. He keeps it close at hand for referencing. ]
Taking the poisonous bite out of cyanide and avoiding other poisons Enrico Uva <[email protected]> Laurenhill Academy, St. Laurent QC Unless you’re a falsely accused, innocent bystander at the scene of a crime, coincidences can be fun in life. I was demonstrating the reduction of permanganate ion (MnO4-) by thiosulfate ion (S2O32-) to my students. As the purple permanganate solution removes electrons from the thiosulfate, the brown product MnO2 appears. It can be more dramatic if HSO3
- is used because the reaction products go completely colourless, but if bisulfite is not available, as was the case in our school, acidified MnO4
- will also do the trick with thiosulfate. On the same day, in a little black notebook1 that I use to keep track of various science tidbits, I came across the strange story of the eastern tent caterpillar, and I decided to share that story with my class. The caterpillars concentrate cyanoglucosides (specifically prunasin) from the leaves of wild cherry that they devour.
Prunasin (notice the cyano group)2 Enzymes then convert the compounds to cyanide, which the caterpillar spits out at its potential predators. Other defensive compounds such as acetone and benzaldehyde are also included in their saliva. Of course, it begs the question, how does such a caterpillar prevent poisoning itself? This is where rhodanese — an enzyme found in the mitochondria of many animals — comes in. This enzyme can convert cyanide (CN-) to thiocyanate (SCN-), which is much less toxic. Most animals are susceptible to cyanide poisoning because the rhodanese is not distributed in the mitochondria of all tissues. This is probably not the case with caterpillars. But where does the coincidence enter the picture? It is the question of where rhodanese gets the sulfur to attach to the cyanide group: from thiosulfate, the same ion (in solution) sitting on our demonstration desk. In other words, the thiosulfate that reduces the permanganate in our demonstration, participates in this reaction to convert cyanide to thiocyanate, hence saving this caterpillar from a toxic fate. Then the following day there was another connection to the demonstration in the news. The Ottawa Citizen reported that paramedics had to treat 11 students at the Higher Learning
Institute for chlorine poisoning. They had acidified potassium permanganate with hydrochloric acid. This was done either deliberately or accidentally, but in either case, the chloride ion was oxidized to chlorine gas by the stronger oxidizing agent, MnO4
-. We had kept our demo safe by acidifying the electron-mugger with vinegar. Sulfuric acid would also have been a safe alternative. Students were awed by another coincidence, and by the fact that in chemistry there’s a fine line between a successful demo and a disaster. Notes and references 1. Enrico’s black notebook
[We decided to show this page of equations to highlight how Enrico collects these tidbits in this book. He keeps it close at hand for referencing. ]
Plenary and keynote speakersJorge Ibáñez Universidad Iberoamericana, Mexico
John Polanyi University of Toronto, Nobel Laureate , Canada
Martyn Poliakoff University of Nottingham, UK
Diane Bunce Catholic University of America, US
Hsin-Kai Wu National Taiwan Normal University, Taiwan
Bassam Shakhashiri University of Wisconsin-Madison, US
Yu-Ling Cheng University of Toronto, Canada
David Fung Chair, Chemical Institute of Canada, Canada
Myra Hauben College of Staten Island, New York, US
Nicholas Leadbeater University of Connecticut, US
Zafra Lerman Lerman Institute for the Advancement of Science, US
Pippa Lock McMaster University, Hamilton, Canada
Stacey Lowery Bretz Miami University, Ohio, US
Carey Supalo Illinois State University, US
Michele Zema University of Pavia, Italy
Of special interest to high school teachers, including sessions focused on:
Using Facebook, mobile devices, electronic resourcesNanoscience in secondary schoolsCreativity in assessment designPOGIL (Process-Oriented Guided Inquiry Learning)
Interactive simulationsGreen chemistry in high school curricula
Go to the website to see much more...
Hands-on, free-of-of-of charge workshops
Special rates for high school teachersEarly bird registration by May 15
$320 full conference; $160 for two days
The first time ICCE has been held in Canada since 1989Find more program information at our website
Take a boat cruise and have dinner on Lake Ontario. Mix and mingle with chemical educators from over 50 different countries.
More special tours of the area are available. (not included in registration fee)
Metro Toronto Convention Centre and the University of Toronto
Sunday, July 13 to Friday, July 18, 2014
10 Chem 13 News/May 2014
An all-natural banana On the next page, you will find a poster from a website created by James Kennedy, a chemistry teacher in Melbourne, Australia (http://jameskennedymonash.wordpress.com). You might have already heard about this poster since his “all-natural banana” has gone viral with two million views. Just think, two million people are now aware of the chemicals in a piece of fruit. His site is worth a visit and you can freely download the PDF of the poster of the “all-natural ingredients of a banana” as well as a variety of other fruit and food, such as blueberries and an egg. You can also order the poster, or better yet a bright and colourful T-shirt. I am definitely getting one! James explains the poster best:
“As a chemistry teacher, I want to erode the fear that many people have of ‘chemicals’, and demonstrate that nature evolves compounds, mechanisms and structures far more complicated and unpredictable than anything we can produce in the lab.”
James has a blog on his site that is worth a read. I would also recommend reading the many interesting comments that the blog generates.
In this blog, James gives this opinion about ingredients.
“I usually care too much about food labels. If something has monosodium glutamate (E621) or high fructose corn syrup (HFCS) in it, I’m probably not going to buy it no matter how healthy or delicious the food looks as a whole. (Strangely, I’d be willing to eat it, though.)
“Some people care about different ingredients such as ‘E-numbers’. I made this graphic to demonstrate how ‘natural’ products (such as a banana) contain scary-looking ingredients as well. All the ingredients on this list are 100% natural in a non-GM banana. None of them are pesticides, fertilisers, insecticides or other contaminants.
“There’s a tendency for advertisers to use the words ‘pure’ and ‘simple’ to describe ‘natural’ products when they couldn’t be more wrong. With this diagram, I want to demonstrate that ‘natural’ products are usually more complicated than anything we can create in the lab. For brevity’s sake, I omitted the thousands of minority ingredients found in a banana, including DNA.”
As an added bonus for chemistry teachers, James also includes a lesson plan to use with the poster. It is a great introduction to organic chemistry — blog post on February 27, 2014. [JLH]
Student-friendly Spectrophotometer makes learning a breezeThe Thermo Scientific™ SPECTRONIC™ 200 Visible Spectrophotometer brings new possibilities to student education:
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10 Chem 13 News/May 2014
An all-natural banana On the next page, you will find a poster from a website created by James Kennedy, a chemistry teacher in Melbourne, Australia (http://jameskennedymonash.wordpress.com). You might have already heard about this poster since his “all-natural banana” has gone viral with two million views. Just think, two million people are now aware of the chemicals in a piece of fruit. His site is worth a visit and you can freely download the PDF of the poster of the “all-natural ingredients of a banana” as well as a variety of other fruit and food, such as blueberries and an egg. You can also order the poster, or better yet a bright and colourful T-shirt. I am definitely getting one! James explains the poster best:
“As a chemistry teacher, I want to erode the fear that many people have of ‘chemicals’, and demonstrate that nature evolves compounds, mechanisms and structures far more complicated and unpredictable than anything we can produce in the lab.”
James has a blog on his site that is worth a read. I would also recommend reading the many interesting comments that the blog generates.
In this blog, James gives this opinion about ingredients.
“I usually care too much about food labels. If something has monosodium glutamate (E621) or high fructose corn syrup (HFCS) in it, I’m probably not going to buy it no matter how healthy or delicious the food looks as a whole. (Strangely, I’d be willing to eat it, though.) “Some people care about different ingredients such as ‘E-numbers’. I made this graphic to demonstrate how ‘natural’ products (such as a banana) contain scary-looking ingredients as well. All the ingredients on this list are 100% natural in a non-GM banana. None of them are pesticides, fertilisers, insecticides or other contaminants. “There’s a tendency for advertisers to use the words ‘pure’ and ‘simple’ to describe ‘natural’ products when they couldn’t be more wrong. With this diagram, I want to demonstrate that ‘natural’ products are usually more complicated than anything we can create in the lab. For brevity’s sake, I omitted the thousands of minority ingredients found in a banana, including DNA.”
As an added bonus for chemistry teachers, James also includes a lesson plan to use with the poster. It is a great introduction to organic chemistry — look at his blog post on February 27, 2014. [JLH]
Teaching and Learning Inquiry in Chemistry Using Bonding
Successful Inquiry Labs for AP Chemistry
ChemSource, the NGSS, and the Particulate Nature of Matter
Putting the Green in the Next Generation Science
For information about housing and travel to Allendale, please visit the conference website.
Additional Planned Events for attendees and their families Cruise on AWRI Research Vessel, Saugatuck Dune Ride, Heritage Hill District with Frank Lloyd Wright Meyer May House, Hoffmaster State Park, Frederik Meijer Garden and Sculpture Park, Fenn Valley Wine Tour, 5K Fun Run, Golf Scramble at GVSU's Championship Golf Course and Brewer's Tour. (not included in registration )
May 2014/Chem 13 News 13
What we can teach with hybrid orbitals Alberto Moniz <[email protected]> Streetsville Secondary School, Streetsville ON
Chemistry has a method of making progress which is uniquely its own and which is not understood or appreciated by non-chemists. Our concepts are often ill-defined, our rules and principles full of exceptions, and our reasoning perilously near being circular. Nevertheless, combining every theoretical argument available, however shaky, with experiments of many kinds, chemists have built up one of the great intellectual domains of mankind and have acquired great power over nature, for good or ill.
E. B. Wilson1
The value of teaching hybrid orbitals has been the topic of recent articles in the Journal of Chemical Education2,3,4 and in this publication.5 Grushow argues that the concept of hybrid orbitals is outdated, with very few valid applications in contemporary chemistry, and only ingrains an incorrect understanding of bonding which students will have to overcome in future learning. In contrast, Landis, Weinhold and Tro contend that a hybrid orbital approach, as a component of valence-bond (VB) theory, is still properly used by contemporary chemists to model electron densities and bonding, and that introducing these concepts does not get in the way of the future learning of students, but provides a secure foundation for more advanced work. It is clear from this discussion that the value of localised models of chemical bonding is still an open question. As a high school teacher, I do not feel qualified to contribute to this debate among professional chemists, but I would like to argue that making our students aware that such debates exist in contemporary science is essential in shaping a deeper and more authentic view of the nature of science in our students. Despite their shortcomings, hybrid orbitals should not be taught as merely a flawed and simplified story we tailor to the limited powers of the teenaged mind. Just getting students through with a fairy tale understanding of chemical bonding robs us of an opportunity to expose them to some profound lessons in the nature and development of the modern science of chemistry. This point is well made by Nivaldo Tro:
Chemical bonding is probably the only place in the curriculum where we teach multiple models for a single phenomenon. This exercise, if done correctly, teaches students a valuable lesson about the nature of scientific models. (Tro in reference 4, page 567)
The best reason to teach hybrid orbitals, as a component of Linus Pauling’s VB theory, is to compare and contrast it with Lewis structures and the delocalized, molecular orbital understanding of bonding. One of the most important goals in science education should be to demonstrate that science is not the static, black and white body of knowledge found in the average textbook. Instead of classifying different models as simplistically right or wrong, we need to help our students compare alternative scientific perspectives in terms of strengths and weaknesses. This
approach encourages higher order thinking, deepens understanding and engages students with a more open, dynamic portrayal of science as the vital human endeavour it is. The teaching of chemical bonding is a unique opportunity in the science curriculum to achieve these goals, but this approach requires an awareness of the logical and historical underpinnings of the different models. Students first encounter chemical bonding with Lewis dot diagrams and structures.6 G.N. Lewis first conceived of these diagrams in 1902 as a teaching tool for undergraduates, but his theory of valence continued to evolve during the subsequent 20 years with the introduction of Bohr’s model of the atom and the development of quantum mechanics (Gavroglu in reference 1, page 48). These humble diagrams, with their surprisingly powerful electron dot patterns, allow us to predict the valence of elements plus the formulae and structures of a large number of simple compounds which, with the introduction of VSEPR theory, leads to the inference of molecular geometries and polarities. It gives us the octet rule, and a way of introducing the formation of ionic and molecular compounds. And most importantly, it gives us the concept of the localized, directional, shared electron pair bond. All this from a non-mathematical, pre-quantum mechanical model largely based on empirical patterns of valence. We do not teach Lewis diagrams because they are right, in many important ways they are not, but they are not merely heuristic tools to be discarded later on — indeed, structural formulae with lines representing the shared electron pair bond are ubiquitous in all of chemistry. We need to help our students appreciate the incredible predictive power of this utterly simple model and respect the genius behind it. But we also need to help students recognize its limitations. This is a chemist’s theory designed for the chemist’s need to predict bonding and structure. It fails as a physical theory to explain why and how bonding occurs and does not say anything about spectroscopic data, which was both the triumph and downfall of the Bohr model. Lewis, who was a leader in physical chemistry and recognized the importance of physics7 to chemistry, continued to modify his ideas until 1923 to better conform to Bohr’s atom.8 It is interesting to contrast the styles and commitments of these two scientists: the chemist and the physicist. Their theories were different because they had different perspectives and different goals: Lewis wanted to explain valence and bonding; Bohr was concerned with atomic structure and the hydrogen spectrum. In each case their work was influenced by the cultures of their respective disciplines and not merely by some abstract notion of a single, otherworldly, objective truth. It is this socio-historical background that is missing in our textbooks. In our rush to make things simple, we often perpetuate a view of science which is disconnected, unengaging and naïve — textbooks are where scientific curiosity and discovery go to die.
14 Chem 13 News/May 2014
After a European tour where he immersed himself in the new quantum mechanics with many of the world’s leading physicists, Linus Pauling returned to Berkeley California in 1931 where he delivered his famous lecture series on “The Nature of the Chemical Bond” (Gavroglu in reference 1, page 61). The very important and pedagogically relevant case of how the carbon atom bonds to form methane will serve to illustrate his results. The ground state electronic configuration of carbon’s valence shell is 2s22p2, which — as I never tire of pointing out to my students — as a kind of discrepant event, does not provide the four equivalent, unpaired electrons necessary to form the methane molecule as predicted by its Lewis dot diagram. Pauling’s breakthrough, which actually came three years prior in 1928 (Servos in reference 8, page 290), was to realize that the 2s and 2p subshells were very close in energy, allowing for the combination of the wavefunctions into four equivalent hybrid orbitals. The higher energy of the hybrid orbital configuration would be more than compensated for by the lower energy of the molecule formed by their combination with the atomic wavefunctions of hydrogen. The result was the four equivalent, localised, shared electron pair bonds with tetrahedral geometry that all chemists know and love. Hybrid orbitals achieve this result because that was what they were designed to do. Pauling was a structural chemist and a pioneer in X-ray crystallography. As such, he was concerned with making the new quantum mechanics consistent with empirically known molecular structures, and he was entirely committed to the basic theory of valence and bonding developed by Lewis (Servos in reference 8, page 290 and Gavroglu in reference 1, page 64). Like Lewis before him, Pauling’s valence bond theory was influenced by his commitment to the goals and methods, that is, the culture of his discipline. When teaching this material, I make it a priority to draw connections between these different models and perspectives. It is important to remember that hybrid orbitals (and orbitals in general) are not physical entities and that hybridisation is not a physical process as it is sometimes taught. When we speak of hybridisation or “orbital overlap” students can get the impression that entities are physically merging and changing into new forms when what is actually going on is the mathematical procedure of combining wavefunctions to create new wavefunctions that better describe the particular physical system of interest. The mathematics involved is far too advanced for the high school level, but that does not mean that we should give students the wrong impression by not stressing to them that this is a mathematical theory. And how exciting to realize that which wavefunctions are used and how they are combined is essentially a human choice, guided by empirical considerations and professional commitments. This is, of course, at the root of the controversy over hybrid orbitals in the first place. Pauling’s valence bond theory was the application of quantum mechanics to Lewis’s model of localised chemical bonding. This links with the drawing of more advanced Lewis structures and the derivation of molecular geometry and polarity based on the VSEPR theory. And when we begin to explore these more
advanced structures, we encounter the concept of resonance.9 Resonance was crucial to Pauling as it allowed him to explain the existence and unusual stability of benzene,10 but really it was an artifact of the theory’s greatest weakness. The valence bond and Lewis theories both assume that molecules result from atoms sharing bonding pairs of valence electrons in localised, directional bonds independently of the atoms’ other non-bonding electrons. A molecule is just the sum of its atoms and the distinct, chemical bonds that hold them together. This commitment to the idea of the localised chemical bond is what the physicist Robert Mulliken called the “ideology of chemistry” in 1935 (Gavroglu in reference 1, page 84). In a way that parallels the relationship between the models of Lewis and Bohr, but without the rapprochement, the controversy between VB theory and molecular-orbital (MO) theory can be similarly characterized as a clash of cultures between the chemical and the physical. Mulliken’s method treated each molecule as a unique system with its own set of molecular orbitals. The molecule is the result of the entire electronic structure of the system rather than the summation of the bonding atomic orbitals of each atom. This results in the possibility of electrons spanning more than just particular pairs of atoms — what is known as delocalized electrons. I teach the resonance structures of benzene as a discrepant event which is better understood by the delocalized bonding model of MO theory. Among its many advantages, MO theory is able to predict, as cited by both Mulliken and Grushow,2 spectroscopic data; but at the price of sacrificing any easy correspondence to the chemist’s concepts of valence and bonding. It is again the choice between the chemist’s concerns for bonding and structure versus the physicist’s commitment to the calculation of spectra and orbital energies. This is not just an issue for the high school curriculum, but a deep historical controversy that has lasted for almost ninety years. As educators, we must be sensitive not only to the bare scientific content of the curriculum but also to the image of science that we implicitly portray to our students. The history of scientific ideas should be an integral part of our teaching as it gives our students the opportunity to develop a deeper and richer understanding of the subject. These ideas are not new, as this statement from the March 1979 issue of Chem 13 News attests: 11
Knowing how the laws of chemistry came to be revealed, through insight, reasoning and logic of many minds, can lead to an enhancement of our own understanding and appreciation of this science.
But these considerations remain stubbornly and increasingly absent from our curricula and textbooks to the detriment of student understanding and engagement. By not allowing the history of science to inform our teaching we close off our subject from the dynamic human realm of the possible in favour of the rarefied, always existing knowledge of the textbook. This omission of context from our teaching in the name of simplification means that students are not given enough information and
May 2014/Chem 13 News 15
insight to construct any real understanding of the subject beyond a kind of rote surface knowledge that will get them through the hoops of the education system but is good for nothing else. Linus Pauling once said that “if you want to have good ideas you must have many ideas.”12 In the age of Google, when all the scientific content we could possibly teach is easily accessible everywhere to everyone, what is the value of the classroom experience? It must be to challenge students to do what no computer can — to think. By incorporating historical context into our lessons we expose students to the human reasoning, and controversies, behind the textbook facts. This opens up a space that makes the construction of deeper meaning by our students possible. Our lessons are more engaging, authentic and meaningful if we punctuate them not with periods, but with ellipses… References 1. Kostas Gavroglu, Ana Simões, Neither Physics nor Chemistry: A
History of Quantum Chemistry. MIT Press, 2012, page 252.
2. Alexander Grushow, Is it Time To Retire the Hybrid Atomic Orbital? Journal of Chemical Education, 2011, 88, pages 860-862.
3. C.R. Landis, F. Weinhold, Comments on “Is it Time to Retire the Hybrid Atomic Orbital?” Journal of Chemical Education, 2012, 89, pages 570-572.
4. Nivaldo J. Tro, Retire the Hybrid Atomic Orbital? Not So Fast, Journal of Chemical Education, 2012, 89, pages 567-568.
5. Michael Jansen, Orbital hybridization — the stork, Chem 13 News. February, 2014. page 4.
6. Often it is Bohr diagrams that are taught first, but these should always be drawn with the same pairing pattern as Lewis diagrams to facilitate the teaching of bonding and valence.
7. Lewis was the author of the first paper published in the US on Einstein’s special relativity in 1908 (Gavroglu, 47).
8. John W. Servos, Physical Chemistry from Ostwald to Pauling. Princeton University Press, 1990, page 281.
9. I would also include the concept of formal charge which is essential for evaluating alternative Lewis structures.
10. Linus Pauling, Nature of the Chemical Bond, 2nd edition, Cornell University Press, 1948. page 129.
11. Quoted from Chem 13 News, February, 2014. Page 15.
12. Linus Pauling, quoted by Francis Crick. The Impact of Linus Pauling on Molecular Biology, Oregon State University Libraries, 1996. http://oregonstate.edu/dept/Special_Collections/ subpages/ahp/ 1995symposium/crick.html. Accessed on March 11, 2014. ∎
Chemicals in the news On April 2, 2014, a chemical explosion at the Greenbrook water treatment plant in Kitchener, Ontario, shook the neighbourhood. A chlorine tank exploded when it was filled with ammonia, leaving a strong chemical smell in the air. Officials said no one was injured in the explosion. Thomas Schmidt, the region's transportation and environmental services commissioner, said there is no risk to the water supply or to people who were outdoors in the vicinity of the plant. http://www.cbc.ca/news/canada/kitchener-waterloo/kitchener-treatment-plant-explosion-due-to-chemical-mix-up-1.2596255 This is a great opportunity to discuss safety as well as having your students propose what happened and write out the chemical equations.
A chemistry pipeline puzzle winners The winners of the December 2013/January 2014 puzzle are Andre Dumais’ class from Hearst High School in Hearst ON and Jessica Bai, a student from Dr. Robert Corell’s class at Princeton High School in Princeton NJ. Both teacher and student will receive a pack of Periodic Table Quest cards donated by Educational Innovations.
A “Not so funny” crostic winner The book-prize winner for solving the December 2013/January 2014 crostic is Gwen Revington from Ontario’s Bluewater District School Board in the Hanover-Walkerton-Chesley area. The quote is taken from Michael Jansen’s article in the October 2013 issue of Chem 13 News.
If we send a message that high school chemistry is all about having fun and not about hard work we insult our students’ intelligence and send them and their parents a false message. Chemistry is not a walk in the park but, if you understand where you’re going, the trip can be rewarding.
A make or break M had dark hair B Jean Hein, editor N intuit C aluminum shed O Reg Friesen D nanotechnology P thudded E situations Q eggwash F eggplants R ethane G nasty business S nodules H conference chair T NFL I haughtiness U efts J Edta therapist V www.uwaterloo.ca K manga W silver bromide L twenty plus thirty
May 2014/Chem 13 News 15
insight to construct any real understanding of the subject beyond a kind of rote surface knowledge that will get them through the hoops of the education system but is good for nothing else. Linus Pauling once said that “if you want to have good ideas you must have many ideas.”12 In the age of Google, when all the scientific content we could possibly teach is easily accessible everywhere to everyone, what is the value of the classroom experience? It must be to challenge students to do what no computer can — to think. By incorporating historical context into our lessons we expose students to the human reasoning, and controversies, behind the textbook facts. This opens up a space that makes the construction of deeper meaning by our students possible. Our lessons are more engaging, authentic and meaningful if we punctuate them not with periods, but with ellipses… References 1. Kostas Gavroglu, Ana Simões, Neither Physics nor Chemistry: A
History of Quantum Chemistry. MIT Press, 2012, page 252.
2. Alexander Grushow, Is it Time To Retire the Hybrid Atomic Orbital? Journal of Chemical Education, 2011, 88, pages 860-862.
3. C.R. Landis, F. Weinhold, Comments on “Is it Time to Retire the Hybrid Atomic Orbital?” Journal of Chemical Education, 2012, 89, pages 570-572.
4. Nivaldo J. Tro, Retire the Hybrid Atomic Orbital? Not So Fast, Journal of Chemical Education, 2012, 89, pages 567-568.
5. Michael Jansen, Orbital hybridization — the stork, Chem 13 News. February, 2014. page 4.
6. Often it is Bohr diagrams that are taught first, but these should always be drawn with the same pairing pattern as Lewis diagrams to facilitate the teaching of bonding and valence.
7. Lewis was the author of the first paper published in the US on Einstein’s special relativity in 1908 (Gavroglu, 47).
8. John W. Servos, Physical Chemistry from Ostwald to Pauling. Princeton University Press, 1990, page 281.
9. I would also include the concept of formal charge which is essential for evaluating alternative Lewis structures.
10. Linus Pauling, Nature of the Chemical Bond, 2nd edition, Cornell University Press, 1948. page 129.
11. Quoted from Chem 13 News, February, 2014. Page 15.
12. Linus Pauling, quoted by Francis Crick. The Impact of Linus Pauling on Molecular Biology, Oregon State University Libraries, 1996. http://oregonstate.edu/dept/Special_Collections/ subpages/ahp/ 1995symposium/crick.html. Accessed on March 11, 2014. ∎
Chemicals in the news On April 2, 2014, a chemical explosion at the Greenbrook water treatment plant in Kitchener, Ontario, shook the neighbourhood. A chlorine tank exploded when it was filled with ammonia, leaving a strong chemical smell in the air. Officials said no one was injured in the explosion. Thomas Schmidt, the region's transportation and environmental services commissioner, said there is no risk to the water supply or to people who were outdoors in the vicinity of the plant. http://www.cbc.ca/news/canada/kitchener-waterloo/kitchener-treatment-plant-explosion-due-to-chemical-mix-up-1.2596255 This is a great opportunity to discuss safety as well as having your students propose what happened and write out the chemical equations.
A chemistry pipeline puzzle winners The winners of the December 2013/January 2014 puzzle are Andre Dumais’ class from Hearst High School in Hearst ON and Jessica Bai, a student from Dr. Robert Corell’s class at Princeton High School in Princeton NJ. Both teacher and student will receive a pack of Periodic Table Quest cards donated by Educational Innovations.
A “Not so funny” crostic winner The book-prize winner for solving the December 2013/January 2014 crostic is Gwen Revington from Ontario’s Bluewater District School Board in the Hanover-Walkerton-Chesley area. The quote is taken from Michael Jansen’s article in the October 2013 issue of Chem 13 News.
If we send a message that high school chemistry is all about having fun and not about hard work we insult our students’ intelligence and send them and their parents a false message. Chemistry is not a walk in the park but, if you understand where you’re going, the trip can be rewarding.
A make or break M had dark hair B Jean Hein, editor N intuit C aluminum shed O Reg Friesen D nanotechnology P thudded E situations Q eggwash F eggplants R ethane G nasty business S nodules H conference chair T NFL I haughtiness U efts J Edta therapist V www.uwaterloo.ca K manga W silver bromide L twenty plus thirty
16 Chem 13 News/May 2014
Snapshot of summer chemical education conferences Kathy Kitzmann <[email protected]> Mercy High School, Farmington Hills MI Many teachers wonder what the differences are between the annual summer conferences that are held for chemistry educators. Why are there different conferences? What is the history of these conferences? How are they organized? Who should attend them? This article will attempt to answer these questions and also provide some anecdotal information. I am a high school chemistry teacher, and I have attended thirteen ChemEd conferences (beginning in 1989) and nine BCCE conferences (beginning in 19960. I have enjoyed attending these conferences and feel they are extremely worthwhile for ALL those who teach chemistry, at whatever level. [Editor’s note: Chem 13 News has added information about ICCE.]
The following table is useful to make comparisons between the conferences. It should be noted that many differences are found from year to year, depending on who is hosting the conference. Whether you decide to attend BCCE, ICCE or ChemEd, you are in for an invaluable experience. These conferences allow educators to meet and share teaching experiences, classroom innovations, favorite demonstrations and laboratory experiments. Participants can take part in hands-on workshops and learn how to engage students in the exciting subject of chemistry! The best part of attending these conferences is meeting with colleagues from all over the country and the world. See you this summer at Grand Valley State University — I am planning to be at the BCCE!
Typically all conferences o are biennial.
(BCCE and ICCE in even numbered years — next in 2014; ChemEd is odd numbered, next in 2015)
o are hosted by universities. o have social events featuring the host city and culture. o have daily plenaries. o welcome guests (for a small registration fee). o have inexpensive on-campus housing available. o have free and paid tours of local attractions for
attendees and guests (such as beer/wine tours). o have opening and closing ceremonies with special
conference speakers.
Unique traditional highlights o BCCE has a tradition since 2004 of having a music night with
Al D. Hyde & the KeyTones — a band of musical chemical educators. Most BCCEs have a 5K walk/run.
o ICCE has a vast number of international attendees and presenters.
The conference moves around to different continents, so tours and events are planned to showcase the host countries. One consistent feature is a chemical demonstration plenary lecture — this year Bassan Shakhashiri, former ACS president, will give this lecture.
o ChemEd introduced the Reg Friesen Tribute Lecture in 1987. The
lecturer is selected to reflect Reg’s belief that teachers can and do make a difference in students’ lives and on the chemistry community. Mole Day breakfast (6:02 am) with the Mole of the Year announced. Mole Day Run is a must — 6.02 km starting at 6:02 am.
14 Chem 13 News/September 2013
discussing different properties of the substance and drawing real-life parallels with quicksand. After two hours, the audience waned and it was time to clean a colossal mess. The once off-white fluid was now a dingy gray, with some hair, dirt, and other small objects floating on the top of the surface. Since we were set up inside, we removed the oobleck by pouring as much as we could into buckets and carting them off into an outdoor dumpster. The pool was rinsed and laid out to dry; however I could never have anticipated the film of cornstarch that coated the floor and walls, connecting hallways, and lab. Hundreds of footprints lined the hall and Dr. Lyle returned after the event to try and remove the mess before our housekeeping staff came into work.
Overall, we received great feedback from our audience, who commented on how enjoyable and cool the activity was for them and their children. For subsequent events, we made the decision to pare down the scale of our tub, however. Instead of a large pool, we decided to use a long, flat, rectangular Rubbermaid container. About forty pounds of cornstarch was required to make the four inches of oobleck, but despite the smaller size, both adults and children could still stand in the tub and take a step or two across the substance. Achieving the desired oobleck consistency was more feasible on a smaller scale, however the shorter tub meant that the more intrepid oobleck-runners would jump right out of the tub, over a taped down tarp, and onto a very slick floor. This tub was used for both
an indoor and an outdoor event, with rave reviews following the outdoor endeavor. Making large oobleck tubs indoors leads to slick, powdery floors, and the outdoor event expedited clean up as we rinsed the oobleck off of the concrete and into the grass. In addition, we were able to add an “Oobleck Egg Drop” from the stairs outside to further engage the audience and better demon-strate how the behavior of the fluid varies at different pressures. While many of our audience members had created cups of oobleck at home and in the classroom, walking on oobleck allowed them to experience the science on a grander scale. I found my own enthusiasm mirrored in the shocked expressions of children who discovered that slow movements allowed them to remove a submerged foot and the grins of adults who joked about “walking on water.” Provided that ample time and materials are available, creating a “walking on oobleck” station enables audience members to get a hands-on, feet-in, immersive experience. *Haley Barrier completed her undergraduate degree in English, with a minor in chemistry December 2012, Duke University. She will begin her study of medicine this fall.
**Dr. Kenneth Lyle, a lecturing-fellow in the Department of Chemistry at Duke University, serves as the lecture-demonstrator and chemistry outreach coordinator.
GlaxoSmithKline–RTP, Biogen Idec–RTP, and the Powell Family Foundation, graciously supports the Duke Chemistry Outreach program.
BCCE 2014 Grand Valley State University Greener on the Grand: Empowering Chemical Educators for a Greener Tomorrow August 3 – 7, 2014 www.bcce2014.org
The Biennial Conference on Chemical Education (BCCE) is a national meeting sponsored by the Division of Chemical Education of the American Chemical Society. It is designed for those who teach chemistry at all levels: secondary school science teachers, undergraduate and graduate students, and post-secondary chemistry faculty. The conference provides anyone teaching chemistry opportunities for interacting with like-minded colleagues in both formal and informal settings.
We are currently accepting proposals for symposia and workshops through the 23rd BCCE website. Please consider submitting a proposal for a workshop, either a half- or full-day, or a symposia. Specific questions can be submitted through the BCCE website to Stephanie Schaertel (workshop chair) or Julie Henderleiter (program chair). Visit and bookmark the 23rd BCCE website for specific information about the conference. This site will be continuously updated with information pertaining to the technical program, registration, housing, and social events as we approach August, 2014.
September 2013/Chem 13 News 17
The questions encourage good lab practice through equipment selection and handling, seeking reproducibility of results through multiple trials, isolation of variables, and safety. Each question originated from a step in the old structured inquiry version of the lab. For example, question 5 above, which brings sample size into the discussion, was represented in step 5 of the structured inquiry procedure5 by
5. Transfer between 1.000 and 1.200 grams of the green crystalline compound into each crucible. Mass the crucibles and crystals, and use the same balance you used in measuring the masses of the empty crucibles.
Unlike the structured inquiry step shown, the guided inquiry question gives students an opportunity to discover the two main factors that determine the mass of hydrate to use in the procedure. Students will need to reserve a portion of the original sample for use in the two subsequent procedures for the total analysis. Also, students become aware of the need for large sample sizes in gravimetric analysis. Because the calculations involve differences in mass measurements, the original samples must be fairly large, or there is a risk of losing significant figures in the result.
Beginning in 2013, the AP Chemistry Course Audit6 requires course syllabi to explicitly list the Science Practices for all labs. Science Practices7 2.1, 2.2, 4.1, 4.2, 4.3, and 5.2 are present in this lab. The next installment in this series will explore conversion of the lab to determine the percent potassium and percent iron by means of an acid-base titration following a quantitative cation exchange. References 1. April 2013, Chem 13 News, pages 8-9.
2. CAS Registry No. 5936-11-8.
3. GCII: what percent of the green crystalline compound is water? Southeast Missouri State University, Cape Girardeau MO 63701.
4. Developing a Procedure for the Green Crystal II Lab. Southeast Missouri State University, Cape Girardeau MO 63701.
5. Green crystalline compound part ii: Determination of percent water. Southeast Missouri State University, Cape Girardeau MO 63701.
BCCE 2014: August 3-7, 2014. Grand Valley State University, Allendale MI (details on page 12)
ICCE 2014: July 13-18, 2014 University of Toronto, Toronto ON (details on page 9)
ChemEd 2015 Kennesaw State University, Kennesaw GA
Attendees
Traditionally, BCCE has been geared toward college chemistry professors. That has changed in recent years so that many of the symposia are also of interest to high school chemistry teachers.
International chemistry educators, (primarily university or college) but sessions focused on high school education are an integral part of the schedule.
Mostly chemistry teachers — high school, AP, IB, etc. Originally created as a forum for high school teachers to share class and lab experiences, now ChemEd has expanded its focus to elementary through college.
Length of conference
5 days; Sunday through Thursday noon
6 days: Sunday through Friday
5 days: ChemEd 2015 will run Tuesday through Saturday (although usually Sunday to Thursday)
Organization The American Chemical Society (ACS) Division of Chemical Education
IUPAC (International Union of Pure and Applied Chemistry)
No formal organization, past chairs and involved teachers have provided informal assistance and guidance
Countries represented
Most attendees from North America (10 countries represented in 2014)
Over 50 countries to be represented in 2014
Mostly Canadian and American; 18 countries represented in 2013
First conference 1970 in Snowmass at Aspen CO.
1969 in Frascati, Italy (initially in odd years)
ChemEd 73 at University of Waterloo ON.
Attendance BCCE 2014 expects 1200-1400 ICCE 2014 planning for 500 Typically 400-800 500 attended ChemEd 2013
Format *Biggest difference between the conferences, in my opinion.
Symposia: authors have 15-20 min to present a paper related to a symposium theme; presenters submit their abstracts and are chosen to participate by the symposium organizers. Papers are often related to chemistry education research or curricular innovations. Workshops: Workshops last for 2-3 hours; some have fees. Poster Presentations: presenters submit a topic for a poster presentation; around 20 to 50 posters are presented during 1-2 hour time slot.
Presentations: mostly longer sessions (45 min); double & triple sessions for workshops and labs, organized by topic Poster Presentations: university dependent (none at ChemEd 2013)
Number of different sessions
BCCE 2014 plans on ~150 symposia, and ~1000 papers; 109 workshops, over 60 poster presentations (18 concurrent sessions)
ICCE 2014 plans on 26 symposia; 12 workshops; over 470 oral and poster presentations (5 concurrent sessions per day)
ICCE 2014: Special high school rate: $320; $160 for 2 days
ChemEd 2013 $300; $100 for 1-day
Guests Guests & family members may attend for a fee. (BCCE 2014, ICCE 2014 and ChemEd 2013 have/had a $50 guest fee.)
Children/family Childcare available at BCCE 2014. Extensive chemistry program for school-aged kids available during sessions, family-friendly activities
Unique to program
BOAFs: Birds-of-a-Feather sessions are informal lunch gatherings to discuss a common topic of interest
Diversity of attendees: high school teachers, undergraduates, graduate students, faculty and industry members from around the globe
Generations symposium: experienced teachers team with new teachers to do demos; Day-long AP Symposium
Is financial assistance available?
ACS Division of Chemical Education sponsors a DivCHED Travel Award. Local sections have grants available.
Significant discount for attendees from developing countries and retirees
CELA (ChemEd Legacy Awards) New attendees/presenters. In 2013, over 40 awards; ChemEd 2011 initiative.
Future conferences
BCCE 2016 University of Northern Colorado, Greeley CO
ICCE 2016 Malaysia
To be announced at ChemEd 2015
[Chem 13 News will be exhibiting at BCCE 2014 and attending ICCE 2014. If you are a teacher local to any of these conferences, you are urged to take a few days of your summer and engage with the chemical education community. These are opportunities not to be missed. For those further afield, it is worth the trip and will inspire your teaching of chemistry.]
18 Chem 13 News/May 2014
Cartoon by Nick Kim, http://www.lab-initio.com
Chem dates is a listing of events that are likely to interest chemistry teachers. To have your program for chemistry teachers listed, phone 519-888-4567, extension 32505, or fax 519-888-9168. Email: [email protected] June 1 – 5, 2014 (Sunday – Thursday): 41st College Chemistry Canada (C3) Conference joint with 97th Canadian Chemistry Conference and Exhibition, Vancouver Convention Centre, Vancouver BC. http://ww.csc2014.ca July 13 – 18, 2014 (Sunday – Friday) International Conference on Chemistry Education, University of Toronto, Toronto ON. http://icce2014.org. See page 9. August 3 – 7, 2014 (Sunday – Thursday): BCCE 2014, Grand Valley State University, Allendale MI. http://www.bcce2014.com. See page 12. October 15, 2014 (Wednesday): Application deadline for Canadian Chemistry Teacher Award. www.cheminst.ca/awards October 18 – 25, 2014 (Saturday – Saturday): National Chemistry Week (Canada). www.chemistry.ca/ October 19 – 25, 2014 (Sunday – Saturday): National Chemistry Week (USA). www.acs.org
October 23, 2014 (Thursday): Mole Day, find information at the National Mole Day Foundation website, www.moleday.org November 13 – 15, 2014 (Thursday – Saturday): STAO 2014, International Plaza Hotel and Conference Centre, Toronto ON. https://stao.ca July 28 – August 1, 2015 (Tuesday – Saturday): ChemEd 2015, Kennesaw State University, Kennesaw GA.
Chem dates
*Renew now* If your subscription expires soon (see top left of your mailing label), please renew on your own initiative. You will save us money and minimize future price increases — rates in box (page 2).
18 Chem 13 News/May 2014
Cartoon by Nick Kim, http://www.lab-initio.com
Chem dates is a listing of events that are likely to interest chemistry teachers. To have your program for chemistry teachers listed, phone 519-888-4567, extension 32505, or fax 519-888-9168. Email: [email protected] June 1 – 5, 2014 (Sunday – Thursday): 41st College Chemistry Canada (C3) Conference joint with 97th Canadian Chemistry Conference and Exhibition, Vancouver Convention Centre, Vancouver BC. http://ww.csc2014.ca July 13 – 18, 2014 (Sunday – Friday) International Conference on Chemistry Education, University of Toronto, Toronto ON. http://icce2014.org. See page 9. August 3 – 7, 2014 (Sunday – Thursday): BCCE 2014, Grand Valley State University, Allendale MI. http://www.bcce2014.com. See page 12. October 15, 2014 (Wednesday): Application deadline for Canadian Chemistry Teacher Award. www.cheminst.ca/awards October 18 – 25, 2014 (Saturday – Saturday): National Chemistry Week (Canada). www.chemistry.ca/ October 19 – 25, 2014 (Sunday – Saturday): National Chemistry Week (USA). www.acs.org
October 23, 2014 (Thursday): Mole Day, find information at the National Mole Day Foundation website, www.moleday.org November 13 – 15, 2014 (Thursday – Saturday): STAO 2014, International Plaza Hotel and Conference Centre, Toronto ON. https://stao.ca July 28 – August 1, 2015 (Tuesday – Saturday): ChemEd 2015, Kennesaw State University, Kennesaw GA.
Chem dates
*Renew now* If your subscription expires soon (see top left of your mailing label), please renew on your own initiative. You will save us money and minimize future price increases — rates in box (page 2).
May 2014/Chem 13 News 19
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Educational Innovations, Inc.®A Practical Guide to Chemistry with a BANG!
You can win a copy of Expose, Excite, Ignite! See this month’s puzzle for details.
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The author focused on the triple S concept: All activities are SIMPLE, reasonably SAFE (hey, this is about combustion) and oh so SPECTACULAR. You'll get step-by-step instructions and photos and all can easily be implemented in your classroom and lab - instant student engagement. Softcover, 119 pages.
BK-490 $15.95
Expose, Excite, Ignite: An Essential Guide to Whizz-Bang Chemistryby Carl AhlersJust when you thought you have seen it all... a book like this comes along and turns your science classes upside down. It's here - the flaming activities they never mentioned at the Chemistry Faculty or banned from your chemistry set. In this one book you will get the explanations, the practical show-how, the safety issues and extension ideas to take your students to the next level. This is not a chemistry recipe book. It is a practical chemistry revelation. No boring recipes on making fizzy volcanic mountains (yawn) - this stuff sizzles.
The author focused on the triple S concept: All activities are SIMPLE, reasonably SAFE (hey, this is about combustion) and oh so SPECTACULAR. You'll get step-by-step instructions and photos and all can easily be implemented in your classroom and lab - instant student engagement. Softcover, 119 pages.
Shakhashiri 49 Chemical Demos DVDIntroduce your students to 49 of the most well known chemical demonstrations, by renowned chemical educator, Bassam Shakhashiri. What could be better? A lesson that works as expected, time after time. No chemical preparation, no clean-up, and no safety concerns!! Demonstrations include: Becker's Multiple Ammonia Fountain; The Mercury (II) Orange Tornado; Diffusion of Poisonous Bromine Vapor; The 72 Mouse Trap Simulation of a Nuclear Chain Reaction; and even our own Ron Perkins' Red, White, and Blue Reaction! (Includes an Instructor’s Guide with references and sample questions.)
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CHEM13 14.05 EI Ad.indd 1 3/26/14 12:15 PM
20 Chem 13 News/May 2014
We are always amazed at the talent of high school students. This photo was sent in by Daniel Harris, a junior student at Scarsdale High School, Scarsdale NY. Daniel is a student of chemistry teacher Elise Hilf Levine and art teacher Dina Hofstetter. With a high-speed camera and the effects of lighting, Daniel simply used the smoke from a candle to take this photo. Dina and Elise continue to run a joint chemistry-art project and submit wonderful entries into our Chemistry in Pictures contest. Be inspired and team up with your school’s Art Department and participate in our annual challenge to capture chemistry in a photo.
![Tesis de Doctorado Dr[1]. Thomas - Evolucin de La Patogenesia Del Lycopodium Clavatum - Beta Fina](https://static.documents.pub/doc/80x56/577dab581a28ab223f8c4d6d/tesis-de-doctorado-dr1-thomas-evolucin-de-la-patogenesia-del-lycopodium.jpg)
