Fingerprint Lab

 

PART 2: Prepare Mystery Fingerprint Evidence

 

  1. Get a tray of required materials (rubber surgical gloves, 3” * 5” white and colored paper, and small fingerprint free objects that your teacher will provide.
  2. Place the fingerprint cards for all your group members at the bottom of the tray
  3. Pick two group members to create visible ink print evidence on paper (#4 below) and two members to create latent oil print evidence on glass, plastic, or cardboard. (#5 below)
  4. To create visible ink fingerprint evidence.

 

    1. One person makes ink prints of your thumb and pointer finger from either hand of a piece of 3 x 5 paper. Label it- Evidence 1
    2. Another person does the same on another piece of paper and labels it-Evidence 2
    3. Place the mystery prints in the tray.

     

  1. To create latent oil fingerprint evidence.

 

    1. Your teacher will tell you which forensic lab techniques (dusting powder, superglue, or iodine crystals) you will be using. If you will be using the dusting powder technique, make your fingerprints on a glass jar or plastic piece. If you will be using the superglue technique or the iodine crystal technique, you can use glass or plastic microscope slides OR paper or cardboard pieces that fit into the fuming jars.
    2. Put a latex glove on one hand before touching the objects. Pick up a clean object with your gloved hand. Hold only the edge. Mark each object as Evidence number three or evidence number four.
    3. Wipe your fingers of your other hand across your forehead or along the sides of your nose to coat them with body oil.
    4. Carefully press the first joints of your thumb and first two fingers straight down onto the object. Then lift them straight up.
    5. Place the object in a tray using only your gloved hand.
    6. On a separate sheet of paper record whose prints are Evidence # 1,2,3,4. give your key to your teacher.

 

PART 3: Identify the Mystery fingerprint Evidence

Your teacher will let you know what forensic lab techniques you will be using to make the latent prints visible.

1. Exchange tray of evidence with another group and form two pairs within your group.

2. Each pair chooses a visible ink print and latent oil print to identify.

3. Use a magnifying lens to compare the visible ink prints to the fingerprint cards.

4. Identify the owner of the print.

5. Follow the techniques, specified by your teacher, for making prints visible with             dusting powder, superglue, or iodine crystals.

6. Use a magnifying lens to compare the print to the print cards.

7. Identify the owner of the print.

8. Check the accuracy of your results by getting the groups key from the teacher.

 

If you are using the Dusting Powder Technique, You will need:

·        Butcher paper to cover table

·        Fingerprint powder or baby powder

·        Fine, soft, and thick cosmetic powder brushes

·        Clear 1-2inch cellophane tape or packing tape

·        3 x 5 paper (contrasting color to powder)

·        Evidence: glass jar or plastic object ( contrasting color to dust)

 

Procedure:

 

1.      working in pairs, have one person put on a plastic glove and pick up the glass or plastic evidence. Tear off a piece of clear tape that is long enough to hold onto the edges and still cover the print. Be careful to not add your fingerprints to the center of tape. Hang tape from edge of the table to use later.

2.      lightly touch the tips of the brush in the powder and tap off the excess.

3.      Lightly dust the glass item in a circular motion until the print becomes visible. Don’t use too much powder

4.      While one person hold the evidence, partner needs to attach one edge of the tape beyond one side of the print and roll the tape over the print, being careful not to make creases or air bubbles. Then you slowly pull tape off.

5.      Tape lifted prints onto paper that is different from the powder color Identify the print pattern and owner.

 

If you are using superglue: you will need:

 

·        Superglue tube

·        Aluminum foil

·        Airtight glass jars

·        Tweezers or surgical gloves

·        Weak heating source

·        Surgical gloves

·        Evidence: glass or plastic microscope slides OR paper pr cardboard pieces that can fit into fuming jar.

 

 

PROCEDURE

 

1.      Blow into the empty fuming jar to add humidity to the air.

2.      work under a fume hood or in a ventilated area. Put a drop of superglue on a small piece of aluminum foil. Use tweezers or surgical gloves to put the foil in the bottom of the fuming jar.

3.      carefully put the fingerprint evidence In the jar so that it does not touch the superglue.

4.      close the lid tightly and place the jar by a warm lamp or on a hot plate set on “low”

5.      Let the fumes from the superglue react with the print for 5-10 minutes. If the print is not visible, add either more heat or another drop of superglue and let it sit for another 5 minutes. If you use too much superglue or leave the print for too long, a layer of white will hide the fingerprint.

6.      when the print is visible, remove the evidence from the fuming jar and identify the owner.

 

If you are using the iodine crystals technique, you will need:

 

·        Airtight jar with small amount of iodine crystals

·        Tweezers or surgical gloves

·        Evidence glass or plastic microscope slides OR paper or cardboard pieces that can fit into fuming jar.

 

PROCEDURE

 

1.      Pick up the fingerprinted evidence jar with tweezers or surgical gloves. If the evidence is flat paper or plastic and will be hard to get out of the jar, attach it to a paper clip on a string.

2.       Work under the fume hood or ventilated area, quickly open the fuming jar containing a few iodine crystals and put the prints in the jar. Let the string hang over the opening onto the outside of the jar. Close the jar tightly.

3.      Let the iodine fumes develop the prints for about 15 minutes

4.      4. Under the fume hood or in ventilated area, open the jar, remove the print, and immediately close the jar tightly. Identify the owner.

 

 

  

 

 

                                                                        Name_____________________ Date_____

 

RIGHT HAND

Thumb

1st finger

2nd finger

3rd finger

4th finger

 

 

 

 

 

Classification of Print Patterns

 

 

    _______                  _______             _______                   _______               ________

 

 

 

 

 

 

LEFT HAND

Thumb

1st finger

2nd finger

3rd finger

4th finger

 

 

 

 

 

 

Classification of Print Patterns

 

    ________                _______               _______                 ______                ________

 

 

 

 

Prints taken by_____________________________