Chromatography

 Chromatography 

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Fingerprint Lab Report

 

You might say that DNA is the only way to find out who the suspect is, but did you know that you have a unique print on each of your fingers? Every fingerprint is unique in its own way and no two fingerprints are alike. A person’s fingerprints are formed when they are a tiny developing baby in their mother’s whom. Pressure on the fingers from the baby touching, and their surroundings create what are called “friction ridges”, the faint lines you see on your fingers and toes.

The role fingerprints play in forensic science is to match the fingerprints to that of with a potential suspect or to match fingerprints to those at a crime scene. When fingerprinting their are three ways you can pickup/see the prints. The three ways to pick up fingerprints, the first way is a latent print. The way to pick up a latent print is to dust the print with black or florescent powder, then lift the print with tape (What we did in class). Another way to collect fingerprints is a plastic impression, this would be a fingerprint in clay or playdoh etc. Lastly, there is the patent print that is visible to the naked eye. These prints can be seen at the crime scene through blood, paint, etc.

When looking at fingerprints you also need to notice and match up the minutiae. The minutiae falls into three categories, Loop, Whorl, and Arch. If you are looking at a fingerprint that is has the whorl shape then you do not have to look at Arch or Loop and visa versa.

fingerprint patterns

When testing out this lab the materials we used were camel, or fiberglass  brushes, a glass jar with finger prints on them, black or florescent powder, tape to lift the print, and index cards. The techniques used while lifting the prints were to put black or florescent powder just on the fingerprint to insure a good lift. Next our group would cut a small piece of tape and place the tape on the glass jar right on the print. Pressing down the tape on the fingerprint then slowly lifting the print and placing it on an index or black card depending on the powder we used.

When looking and comparing fingerprints you should always compare minutiae to see if the two prints you are comparing actually match, minutiae are different patterns in the fingerprints.

minutiae2

In the diagram below I am comparing two fingerprints the circles are connecting the similar minutiae.

  1. Red- Tented arch
  2. Light Blue- Whorl
  3. Green- Arch
  4. Purple- Fork (Bifurcation)
  5. Island – Island or short ridge
  6. Orange- Eye (Enclosure or island)
  7. Black- Spur or hook
diagram.png
With these two prints compared to each other, I am comparing the prints of Monika. I have chosen to compare these two because they have some similarities, the other suspect I am looking at would be those of Jessica. I have eliminated the other suspects because the prints are not even close to matching. I do not think these fingerprints match, they do have some of the same minutiae patterns but are not exactly  alike. I also believe if the florescent fingerprint lifting would have came out more clear we could compare the two prints better.
 During this project I have learned that it is very hard to identify fingerprints with the naked eye but most importantly I have learned how to dust and lift fingerprints. I have also learned the different types of minutiae to compare the prints. Lastly, I have learned that this process is not like CIS. This process takes months with all the fingerprints that need to be examined.

Lift latent fingerprints

Materials used: 

Black powder, Fiber glass brush, camel hair brush, feather duster, tape, beaker, and my own fingerprints 

Step by step:

1: Grab all of the materials listed above

2: run your hands through your scalp or apply Chapstick to lips and pat your fingers on the lips.

3: grab your beaker to wear you can see the prints on the glass.

4: place one of the three brushes into the black powder then gently brush the powder onto your fingerprint.

5: cut a small piece of tape out and place the tape onto the fingerprint that is on the glass beaker

6: once you have your print on the tape, place the tape on an index card.