2015 - 2016
Science IV: Optional Unit
Forensics Lab Manual
TABLE OF CONTENTS
Chromatography Lab ............................................................................................................................................................. 1
Hair and Fibre Lab................................................................................................................................................................... 4
Blood Typing Lab ..................................................................................................................................................................... 7
Fingerprinting Lab .................................................................................................................................................................. 9
Fingerprinting: Multiple Methods .................................................................................................................................. 11
CHROMATOGRAPHY LAB
Students will learn how to properly use the technique of paper chromatography to
make a chromatogram.
Purpose
To use paper chromatography to identify the pen used in writing a note.
Materials:

Filter paper (coffee filters can be used)

Number of different type pens with the same colour ink

Test tubes or other containers to hold the filter paper. A chromatography tank
would be ideal, but is not necessary.

Water, alcohol, or water / alcohol mix

Pencil

Ransom note
Procedure:
1. Cut the filter paper into equal-sized strips (one for each type of pen) that will fit into
the test tubes or other container being used, one strip for each pen plus one for the
letter from the ransom note
2. Mark a pencil line about 1.5 – 2 cm from the bottom of the strip.
3. Place a dot of ink on the line of each filter paper strip. Try to make the dots of equal
size - about the size of the bullets in the materials list.
4. Cut out one letter from the ransom note.
5. Tape the letter from the note to the filter paper making sure the tape does not block
the movement of water up the filter paper above the letter. Be certain that the letter
is touching the filter paper.
6. Place water in the test tubes to a depth of 1 cm and label the tubes.
7. Place each of the strips in a separate test tube and label the tube; be sure the water
does not touch the dot initially.
8. Let the water soak up the strip for 30-60 minutes, until the water line is about 1 cm
from the top of the strip.
9. Remove the strip from the test tubes and let dry.
10. Add these strips to the results section of part one for this project.
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Part Two:
Purpose: To demonstrate that paper chromatography can be used to test substances other than
ink.
Materials:

Filter paper (coffee filters can be used)

Number of different candy coated chocolates (Smarties or M & Ms for example)

Test tubes or other container to hold the filter paper. A chromatography tank would be
ideal but is not necessary.

Water

Pencil
Procedure:
As for part one with the following adjustments.
1. Make sure the candy is slightly wet so that it will be easier to get a sample of the coating.
When making the dots it will help to rotate the filter paper while holding the candy on its
edge.
2. You may choose to test
a. Only the same colour from different types of candy (red Smarties compared with
red M & Ms)
b. Various colours from one type of candy OR
3. Include your dried chromatography strips in your data section.
4. Eat any extra candy
5. Clean up your station, return washed test tubes to racks and shelf, dispose of garbage
appropriately.
Data: Include the chromatograms or a picture of your chromatogram.
Analysis:
1. Explain the scientific basis of why chromatography can be used to separate and identify
different substances that appear the same.
2. Describe two ways in which chromatography could be used to solve a crime.
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3. Which pen was used to write the ransom note?
Conclusion:

Make a suggestion / prediction of how the materials / procedure could be changed to obtain
results from pens that did not run.

Identify possible sources of error in this lab.

Suggest other substances that may be related to crimes that could be identified through
chromatography.
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HAIR AND FIBRE LAB
Purpose:

Students will learn how to use a compound light microscope.

Students will gain first hand practice at making careful and detailed observations for the
purpose of identifying very subtle differences in hair and other fibres.
Materials:

Sample of a letter “e”

Variety of cloth samples (some should be very similar in type and colour)

Variety of hair samples (you may wish to use real human, fake human, and / or animal)

Magnifying glass, light microscope

Microscope slides

Coverslips

Water
Procedure:
Part One:
1. Make sure your microscope slide is clean.
2. Place a drop of water on the center of the slide.
3. Using tweezers, place a letter that has been cut from paper on the water.
4. Slowly lower the coverslip over the letter.
5. Place the slide on the microscope’s stage.
6. Ensure the lowest power objective lens is pointing to the slide.
7. Turn coarse adjustment knob to raise the stage.
8. Look through the eyepiece while turning the coarse adjustment knob to focus the image.
9. Move the medium power lens in place and refocus, if needed.
10. Move the high power lens in place and refocus using the fine adjustment knob, if needed.
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11. Move the stage toward you and away from you and left and right and note how the image
responds. (Hint: be sure you have the answers to Questions 1 in the analysis section)
Part Two:
1. Label each cloth sample with a number or letter.
2. Observe the sample with a magnifying glass and sketch your observations in the data
section of your lab report.
3. Re-examine the cloth samples with a dissecting microscope and sketch your observations in
the data section of your lab report.
4. Record descriptions of texture, colour, etc. for each cloth sample.
5. Examine the hair samples using a light microscope, record observations in the data section
of your lab report (this may be sketches or photos taken with a digital camera)
6. In the observation recordings for the hair, include descriptions such as split ends, colour,
relative thickness, etc.
Part Three:
1. Obtain the hair and cloth samples found at the “scene of the crime”.
2. Examine the samples as you did with the known samples from part one.
3. Record observations.
Data: Include sketches / pictures of the specimens you viewed under the microscope.
Analysis:
1. You may make drawings to answer these questions.
a. How did the object (letter e) look on the slide and how did it appear under the
microscope.
b. When moving the stage / slide toward you, in what direction did the object move?
c. When you move the stage / slide from left to right, in what direction did the object
move?
d. If you have an object near the right of your field of view and you want to move it into
the center of the field of view, how would you move the stage / slide?
2. From your observations, which cloth sample matches that found at the crime scene?
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3. What hair sample matches the one from the crime scene?
Conclusion: Comment on
1. What are some limitations of this type of evidence?
2. Explain the usefulness of this type of physical evidence in solving a crime.
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BLOOD TYPING LAB
Purpose:

Students will learn how to conduct a blood typing technique to determine if a blood sample
is type A, B, AB, or O and Rh+ or Rh-.

Students will apply their knowledge of blood type to scenarios.
Materials:

Antiserums (A, B, and D)

Blood samples

Spot plates, hem tags, or microscopes slides

Toothpicks

Eyedroppers
Procedure:
1. Place 2-3 drops of anti-A serum, anti-B serum, and anti-D serum (to test for Rh + / -) in
separate wells of the spot plate or on separate spots on the microscope slide.
2. Wipe finger (middle is best) with an alcohol wipe.
3. Use a sterile lancet to pierce you finger.
4. Squeeze if you need to, to obtain blood.
5. Using a separate toothpick for each serum, transfer 2-3 drops of blood to each serum and
stir.
6. Wait 15 – 30 seconds (may be up to 1 min for the anti-D serum) and record your results in
the data section of your lab report. [Clumping indicates a positive test. For example, if you
blood clumps in the anti-A serum you are positive for type A blood.]
Data: Include a picture / sketch of your results.
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Analysis:
1. Why is it important to use a fresh toothpick to transfer the blood samples to each
antiserums?
2. The victim of a crime is known to have type A blood. The suspects for the crime and their
blood types are listed below. Two blood samples were collected from the crime. One of the
samples has been confirmed through blood typing and DNA fingerprinting to be the victim’s
blood. The second sample was determined to be type AB. Which of the flowing suspects
would you investigate further based on this information?
o
Susan – type B blood
o
Troy – type A blood
o
Pat – type AB blood
o
Robin type – O
3. When there is blood at a crime scene, what are three ways that it can be useful in solving the
crime?
4. Identify and describe one situation, other than a crime, when the ability to determine blood
type would be useful.
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FINGERPRINTING LAB
Part One
Purpose:
Students will gain experience with taking fingerprints.
Materials:
 Fingerprinting kits
 Reference prints
 Magnifying lens
Procedure:
1. Rub the ink strip to warm the ink and then gently pull the strip apart.
2. Firmly press one digit on the ink strip and have a classmate firmly press your digit onto the
fingerprint card in the position that matches the digit you have inked. DO NOT roll your
digits as this may cause smudging of the print.
3. Repeat with other digits.
4. Using the reference prints, identify your prints’ patterns.
5. Choose the best set of prints from your group and include that set in the data section of your
lab report.
Part Two
Purpose:
Students will gain experience with analyzing fingerprints from a crime scene.
Materials:
 Fingerprint database
 Fingerprint from the crime scence
 Magnifying lens
Procedure:
1. Obtain a copy of the fingerprint lifted from the crime scene.
2. Compare the suspect’s fingerprint to the fingerprint database marking areas of similarity on
the crime scene print.
3. Include your analysis of the crime scene fingerprint (include the name of the culprit) in the
data section of your lab report.
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Analysis:
1. What is one situation in which fingerprint are more useful than a DNA sample from the
crime scene?
2. What are some sources of error in fingerprinting?
Conclusion:
Comment on the challenges of matching an unidentified fingerprint to database.
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FINGERPRINTING: MULTIPLE METHODS
Purpose
The purpose of this activity is to
• collect and preserve fingerprints using various techniques,
• analyze fingerprints by type
Safety, Handling, and Disposal
Safety glasses must be worn during dusting.
Materials
Be sure to list the materials you use in this section of your lab report.
Procedure
I. Iodine fuming
1. Use forceps to pick up a piece of the clean bond paper. Be careful not to touch the paper.
2. Rub your right index finger against your nose, then SLOWLY roll that finger across the
center of the paper. Use the forceps to hold the paper while you write your name on it.
3. Place the piece of paper in a jar with iodine crystals.
4. Seal the jar, and let it sit until the fingerprint “develops” (approximately 20 minutes).
5. Attach the paper to the data section of your lab report.
II. Cynanoacrylate (Superglue) fuming method
1.
2.
3.
4.
5.
6.
Obtain and clean two glass slides.
Rub your right index finger against your nose.
Roll your right index finger once on the center of one of the glass slides.
Put one drop of glue on a small piece of aluminum foil and place the foil inside a jar.
Carefully add the slide, close the lid, and put the jar on a hot plate that is set on “low.”
Repeat steps 2–3 with the other slide, and then proceed to part III below with the second
slide.
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III. Dusting with powder
1. Using your second slide from part II above, lightly touch the brush to the black dusting
powder. A small amount of powder works best.
2. Dust the slide using a gentle, circular motion; tap the slide on its edge to remove excess
powder.
3. Put a piece of clear tape over the print, sticky side down; rub very lightly from top to
bottom, and lift the tape.
4. Attach the tape to your data sheet.
5. Repeat steps 2 – 4 with the slide you fumed in part II.
Data
From Part I: Iodine fuming method (attach paper) of your print. Below the paper, label your print
with its classification
From Part III: Attach tapes from Part III above (Dusting & Cyanoacrylate Fuming plus Dusting),
label your prints with their classification. If you were unable to lift the prints from the slides, simply
tape the slide to the report.
Analysis
1. Which method showed the fingerprints most clearly?
2. Why is it necessary to use different fingerprinting methods at crime scenes?
3. Why was it important to use the same fingerprint for each fingerprinting method?
Conclusion
Give 1-2 limitations or challenges of each fingerprinting method. Identify 1-3 possible sources of
error you may have encountered in this lab. How could you reduce the chances of these errors reoccurring if you were to repeat the lab?
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