Crime Lab Activity
Kathy Paris
Packet Number ________
(Please return)
In this simulation, you will play the role of a police scientist who must examine the clues found at the
scene of the crime. Your job is to find out who did the crime. After
all your tests, you must present your data/evidence and the name
of your suspect to the prosecuting attorney, Mrs. Paris, to see
if the evidence is strong enough to prosecute the suspect. The
crime was very serious, someone was stealing food from the Bethel
cafeteria and selling it to a catering service. School officials
are very worried about the sanity (cleanliness) of the criminal
and about the health of the people served by the catering service.
Grading is based upon the following (total
of 70 points to be divided by lab partners):
- Evidence (data) sheet-Were all the tests
run? Were complete results recorded accurately? (up to 25 points).
- Correct lab procedures including wearing
goggles (up to 10 points)
- Is suspect correct (up or 10 points)
- Were reasons for choosing the suspect valid?
Complete? (up to 10 points)
- Cleaned up trays, lab areas, equipment
(up to 10 points)
- Returned tray with clues and lab supplies
in same condition as receives (up to 5 points)?
Part 1-Basic Instructions
- Work in groups of two. Points received will
be divided in half.
- ALWAYS WEAR GOGGLES WHEN WORKING WITH
CHEMICALS!!!!!!!
- You will be given a tray of clues linking
one of the ten suspects to the horrendous crime--that of stealing
food from the cafeteria and selling it to a catering service.
- To determine who did the crime, you must
identify animal fur from pets, whether or not blood was found
at the scene, clues involving food, and any other clue in your
tray.
- You will be given a suspect list from which
to choose the guilty party.
- Once you have narrowed the field of suspects
the two, you may ask the evidence clerk (alias Mrs. Paris, she
works two jobs) for a sample of the suspect's hair and fingerprints.
- Accurate, complete records are a must or
the prosecuting attorney will throw out the case. Careful drawings
and observations are to be recorded on the "Evidence Sheet".
Part 2-Lab Procedures:
- GOGGLES MUST BE WORN FOR ALL CHEMICAL
TESTS!!!!!!
- Starch Test (Iodine Test):
- Take two clean test tubes and label 1 and 2.
- Add 20 drops of water to each.
- Use a toothpick to add less than a pea
size amount of sample (no more!) to tube #2.
- Add a few drops of iodine to both.
- Tube #1 is a control or comparison tube;
tube #2 is the experiment. (Why?)
- If iodine turns bluish black or black,
it means starch is present. If the color remains brown, no starch
is present.
- Rinse out the test tube before the next
tests--use test tube brush if need be.
- Record data.
- Monosaccharide Sugar Test (Benedict's
Test):
- Take two clean test tubes and label 1 and 2.
- Add 20 drops of water to each.
- Add less that a pea size amount of sample
to teat tube #2; shake to mix.
- Add 5 drops of Benedict's solution (blue)
to both.
- Put both test tubes in a bath of boiling
water for 5 minutes.
- If Benedict's blue color turns green, yellow,
orange or red, it means a monosaccharide sugar is present (not
a disaccharide sugar like sucrose or table sugar).
- Tube #1 is the control; tube #2 is the
experiment. (Why?)
- Rinse tubes-use brush if need be.
- Record data.
- Fat Test
- Take two small piece of brown paper bag
(a few inches in size).
- If the sample is a liquid, put 1 drop on
a piece of brown paper bag.
- If the sample is a powder, add a pea size
- amount to a test tube and add 5 drops of water. Mix by shaking
- or stirring with a glass rod. Add 1 drop of this mixture to a
- piece of brown bag.
- For the control, put 1 drop of water on
another piece of brown paper.
- Let samples dry.
- If a grease spot remains after drying,
fat is present.
- Rinse out tubes.
- Record data.
- Protein Test (Biuret Test) :
- Take 2 clean test tubes; label #1 and #2
- Add 20 drops of water to each tube.
- To tube #2 add a pea size amount (no more)
of sample.
- Carefully add 5 drops of Biuret
to both. Mix with clean glass rod.
- If a pink or purple color appears, protein
is present.
- Tube 1 is the control and tube 2 is the
experiment(Why?)
- Rinse out tubes use brush if need be.
- Record data.
- Use the microscope to examine any animal
parts found at the scene. Put the part on the slide (if not already
mounted), add a drop of water and gently put on a cover slip.
Observe under low power and draw what you see in as much detail
as possible; note color, texture, shape, etc. Record your information.
- Use the microscope to examine any hair
or fur-follow procedure in #6 above. Can you tell if the hair
belongs to the human animal or another animal (mammal)?
- Examine any blood samples. Is it really
blood? Use the microscope and look for red blood cells. Draw
what you see and note any details on your evidence sheet.
- Examine any other clues found and the scene--note
all details (color, shapes and other descriptive information)
and record. Remember, detail is essential if you want a conviction.
- After all clues have been examined and
details recorded, narrow your suspects down to two. Now you may
ask the evidence clerk for a sample of the two suspect's hair
and fingerprints.
- Examine the hair sample with the microscope
and record details; examine the fingerprints and record the details.
- Prepare your final report as to who you
think did the crime and explain the evidence that will help convict
that person.
- Return all clues to respective bags, bottles,
etc. and neatly put back into clue tray. Clean up your area,
wash all tests tubes with a test tube brush and return materials
and clue tray to your larger carrying tray.
- Turn in the evidence sheet with your clue
tray letter, your names and your period.
- Return this packet to the prosecuting attorney
(Mrs. Paris).
Crime Suspect List
- Todd is a baker at the local Safeway
store. He often samples his creations, but prefers candy and
other sugary items. He lives in a inexpensive apartment near
the South Hill Mall. He has a pet that hisses. He often cuts
his hands either on the job or when he cleans pebbles in his pet's
tank.
- Eileen has two beautiful Labradors
which she takes with her on her field work in geology (studies
rocks) for the government. She often uses red paint or dye to
mark the boundaries of the work area. Like most of us, Eileen
loves starchy foods especially chips and potato snacks. You could
almost track Eileen by the trail of potato chips she leaves behind
after her field studies.
- Mary is a botanist (one who studies
plants). To study her beloved plants, she often has to use a
scalpel to cut and graft pieces together. Sometimes she gets
a bit rushed and cuts herself. To ease the discomfort of the
cuts, Mary often uses powder. She has a reptile pet that stays
in the lab and likes to play hide and seek. Mary wastes a lot
of time finding her pet. Mary's preferred foods are high in protein
because she mistakenly thinks this will help muscles (she doesn't
realize she only needs a few ounces on day and any excess puts
stress on her liver, kidneys and heart). Once in awhile she will
eat a few life savers.
- Shelly is a marine biologist who
loves the ocean and all its life forms. She just purchased an
older boat which she painted a beautiful red. Shelly has a hissing
pet named Phred and it loves peanut butter and jelly sandwiches.
Phred loves to have a rub-down with powder.
- Rob is a janitor and maintenance
man for the Boeing plant at Frederickson. He often paints the
offices and work areas--red seems to be a popular color. His
job also requires that he repairs items that don't work. He often
cuts himself doing this part of his job. Since Rob is a vegetarian,
he usually has a starchy food plus a big salad with an oily dressing
for lunch.. He has a pet that doesn't require a lot of attention
since Rob works at nights. All it takes is throwing a few flakes
of food (usually containing starch) on the top of the water in
the tank. Since his pet is aquatic and is used to cold water,
Rob doesn't have to heat the aquarium.
- Nancy is a secretary and she holds
the work's record for typing-- 267 words per minute!! The only
time she cannot type this fast is when her Persian cat , Lady,
walks across the keyboard. Lady loves to play and often scratches
Nancy deep enough to cause bleeding. To distract Lady, Nancy
often throws her pieces of fried chicken.
- Bob has a very unusual job--he's
a grave digger. He owns a cat names Morticia who loves to eat
starchy foods. After working on a grave site, Bob's hands are
sore and bleeding and he often powders them to make them feel
better. Bob's favorite foods are from greasy hamburger joints.
- Don works at the same cemetery as
Bob, but he is the grounds keeper. He must plant the flowers
and shrubs, dig up the weeds, mow the lawn, etc. He often hurts
his hands and he uses powder of soothe them. He feeds his pet
goldfish, Bo, glucose every day after work. Don is a very hard
worker and is often complimented for the work he does at the cemetery.
His favorite lunch is french fries.
- Verne is a fisherman. He is known
for his ability to sense where the fish are biting and also for
his ability to stand upright even in a hurricane. His dog Brittany
always hides under the freshly painted bunk in a storm. Verne
tempts his pup with breadsticks or bread loaded with peanut butter.
- Sam just purchased a nursery on
Canyon road. He wanted to fix up the place a bit, so he painted
the surrounding fence red. He has an unusual pet named Muffin.
Muffin is a pet rock with a terrific personality and very limited
needs. Sam loves, loves, loves oreo cookies that are loaded with
sugar and starch.
Thank you to Judith Ann Dayner who teaches
at the Northern Highlands Regional High School in Allendale, New Jersey for the idea of a crime lab. Although the original lab
was her idea, I have modified it over 50%. I wrote these instructions
and the evidence sheet. The suspect list has been modified to
use the names of my family members. I also changed the description
of these suspects.
Kathy Paris, Bethel High School
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