You better do well with this You better do well with this PowerPoint! PowerPoint!
Paper Chromatography Fingerprints DNA evidence Shoeprints & tire treads Soil Spatters Polymer Testing/ Natural and Man-made
substances (I’ll try my best with this one since I barely know much about it myself.)
What we’re covering…
1. Take a coffee filter and draw a dot on it with the substance given
Paper Chromatography Procedure
2. Place the coffee filter over the cup of water. Make sure that the water doesn’t directly touch the substance dot on the filter.
Instruction: Students will analyze evidence from paper chromatography (ink pens, juices, Kool-Aid, etc.). The paper chromatogram(s) will be collected with
the score sheet. No calculations are expected to be performed.
After the procedure the water should have started
to seep up towards the ink, causing colors to run.
Paper Chromatography Results
It should look vaguely like this when you’re
done.
Just as a suggestion, try to do this experiment first during the experiment that way the water can seep
through for a little longer. Not only that , but it’s simple and quick and easy to get out of the way.
This Website contains the entire experiment:
http://www.yesmag.bc.ca/projects/paper_chroma.html
Watch this youtube video to help understand how to conduct the experiment:
http://www.cleanvideosearch.com/media/action/yt/watch?videoId=-fs5btFKdXA
Websites for Chromatography
There are 3 types of
fingerprints:1.Arch
2.Whorl3.Loop
Fingerprints
Instructions: Students may be asked to identify different patterns on fingerprint evidence such as the difference between arches, whorls,
and loops.
You should know that no 2
fingerprints are alike.
You can see one way to tell the difference between the three types is where their deltas and cores are located.Delta: Triangular area usually shaped like a T-junctionCore: Center of the pattern.
Differentiating Fingerprints
Loops have one or more ridges entering from one side, curving, and then going out the same side it entered. The ridges in loops double back on themselves. All loops have elements called a delta and a core. About 65% of fingerprints have loops.
Loops
Whorls have a circular pattern and have at least two deltas and a core (center of the circles). Whorls look a little like target shapes or whirlpools – circles within circles. Whorls make up 35% of patterns seen in human fingerprints
Whorls
Arches are the least common pattern making up
only 5% of all pattern types. Arches are ridgelines that rise in the center and create a wave like
pattern. The ridges enter from one side and exit the other side with a rise in the middle. They do
not have a delta or a core and can be broken into two sub-groups:
Plain arch – which has a gentle rise.Tented arches - have a steeper rise than plain arches.
Arches
Arches (Cont.)
Websites for Fingerprints
Check out this website for a more in-depth explanation:http://soinc.org/sites/default/files/uploaded_files/
crimebusters/Fingerprinting.pdfThis has more specifics on the types of fingerprints:
http://www.odec.ca/projects/2004/fren4j0/public_html/fingerprint_patterns.htm
TAKE A BREAK WITH THE DINORAWR!!!
TAKE A BREAK WITH THE DINORAWR!!!
Match the DNA found at the crime scene with
one of the suspects The bands are lengths of DNA strands located o that
person's chromosomes The dark bands represent the end/beginning of a new DNA
strand The more bands that match a certain sample the greater
probability that their DNA are the same.
DNA Evidence
Instructions: Students may be asked to compare DNA chromatograms/ electropherograms from materials found at the scene to those suspects.
Similar to this, but in black in white.
What the Picture will look like
Shoeprints/ Tracks
Just match the print found at the crime scene with the one of the suspect’s and explain how you got that conclustion.
http://soinc.org/sites/default/files/uploaded_files/crimebusters/Tracks.pdf
I will add this part soon!
Polymers/ Fibers