CeAnn Chalker

ceann@chalker.org

Patrick Chalker

patrickchalkerso@gmail.com

Students will make:Metric Estimations

thenMetric Measurements

on identical objects

*Mass

*Volume

*Density

*Area

*Force

*Distance

*Time

*Temperature

*Students rotate between 15-30 stations for each of the two parts of the event

*Supervisors furnish all pencils, paper, and measuring devices

*Teams may bring non-programmable calculators for the Measurement Part only.

*Property to be estimated/measured and Units of Measurement will be given at each station.

*Approximately 30 seconds for each station

*All answer recorded on form provided by Event Supervisor

*Answer form MUST be turned in before Measurement Part begins

*Students may not use any kind of measuring device (fingers, pencils, clothing, paper, etc.)

*Students may not Touch or Feel any objects unless specified in directions

*NEW!!! Students MUST be allowed to “heft” an object if the mass is to be estimated.

*Approximately 60 seconds per station

*All answers recorded on new form provided by Event Supervisor

*Measurements are made using the instruments supplied at each station

*All objects will be measured by the Event Supervisor prior to the competition using the same instruments the students will use

*To receive points, 3 requirements*Proper Resolution

*Estimated digit Appropriate for the Instrument

*Proper Unit of Measurement

Ex. – Answer should be 17.25 grams or 17.25 g on a standard Triple Beam balance

Wrong answers would include –

17.2 grams, 17.2 g, or 17.25

*Direct Measurements - not involving calculations, readings directly from an instrument (e.g. length, volume, mass, etc.)

*Calculated Measurements - measurements that require mathematical calculation to achieve (e.g. calculating the density of an object, height using triangulation, surface area, velocity, etc.).

*Students record measurement to +/- 3 of the estimated digit of the instrument’s resolution.

*Direct Unit Conversions are considered Direct Measurements.

*The smallest actual graduation or markings on the instrument

*A rock has a mass of 56.54g. Using a triple beam balance to find that mass.

*A line on the floor is 187.43cm. Using a meter stick to measure the line a student adds 100cm to 87.43 cm to come up with 187.43cm

Ruler has the smallest resolution of 1 mm*Width of object #1 - Measurement of 209.3 mm

* Answers between 209.0mm - 209.6 mm would be correct

Triple Beam Balance has smallest resolution of 1/10th of a gram

*Mass of rock – Mass of 37.26 grams

*Answer 37.23 grams – 37.29 grams would be correct

*Students take direct measurements and make mathematical calculations obtain the correct answer.

*More difficult to obtain exact answer

*Various points are awarded for answers within .5%, 1%, and 2% of the correct value.

Surface Area *A rectangular box with dimensions 10.62 cm x 4.63 cm x 4.63 cm. To calculate the surface area 2(4.63x4.63) + 2(4.63x10.62) + 2(10.62x4.63) = 42.8738 + 98.3412 + 98.3412 = 239.5562 cm2

*A circle with the diameter of 9cm, the area of that circle is 3.14159 x 4.52 =63.6171975 cm2

*Both parts (Estimation and Measurement) are rated on accuracy

*Rankings are the highest combined score

*Three separate methods of scoring are used

Points based upon the percentage of the correct value for each station

*5 pts – Answers within 5%

*3 pts – Answers within 10%

*1 pt – Answers within 20%

*5 pts – Answer expressed to the instrument's resolution +/-3 of the estimated digit

*0 Pts – All other Answers

Points based upon the percentage of the correct calculated value for each station

*5 pts – Answers within 0.5%

*3 pts – Answers within 1.0%

*1 pt – Answers within 2.0%

*0 pts – All other answers

*Break everything down to the fundamentals

*Useful Formulas

*Finding new things to measure

*Conversions and units

*Comparing size and mass to known objects

*Estimating time by average

*Crazy (but measureable) stations

*Measuring irregularly shaped objects

*Massing something on an open hand

*Using a triple beam balance under time constraint

*Items that seem easy but are very difficult

*Approaching measurements in the same way EVERY TIME

*Practicing measuring with time

*Coaching confidence (and a bit or arrogance)

*Teamwork, dividing the workload

*Mental math

*Put school name and team # on EVERYTHING!

*Put labels for units on EVERYTHING!

*Look at the measuring tool first, and then the object to measure second.

*Check to see if measuring devices are zeroed or in need of zero-ing.

This is just a sampling of formulas students should know, there are many more to learn.

*F=ma, Force = mass x acceleration

*A=∆V/∆T (Acceleration = change in Velocity divided by Change in time)

*A=(V2-V1)/(T2-T1)

*SA = πr2 + πrl (surface area of a cone)

*SA = 2ab + 2bc + 2ac (surface area of a rectangular prism)

*Surface Area of a Sphere = 4 pi r 2

*Surface Area of a Cylinder = 2 pi r 2 + 2 pi r h

*g=-9.81 m/s2 (Earth’s gravitational constant)

*1 N = 1 kg (m/s2)