.

Crime Busters Description: Students will evaluate crime scene evidence to determine who committed a crime. Students

may be expected to test unknown powders, use paper chromatography to identify ink, and

match fingerprints, shoeprints, tire prints, and more.

Number of Participants: 2 Approximate Time: 30 minutes

Event Parameters:

Will be provided at event:

A list of possible powders.

Water, vinegar (CH3COOH), and iodine solution (KI3)*.

Plastic cups, black paper, and toothpicks.

Materials to make a chromatogram

Pencils

Splash Proof OSHA Approved Chemical Safety Goggles. Students must wear safety

goggles during the entire event.

Students are allowed to bring:

An 8.5” × 11”, 2-sided sheet of paper, with any notes on it. One sheet per team.

A magnifying glass.

Competition: All parts will be provided at the same time, and they are to be completed in no particular

order.

Part A: Powder identification

The powders may include: salt, granulated sugar, powdered sugar, flour, cornstarch, baking soda, powdered Alka-Seltzer, powdered gelatin, corn meal, and yeast.

Each team will be given 6 vials containing powders. Each vial will contain 1, 2 or 3

powders. Vial A will contain the powders collected at the scene of the crime, while

Vials 1-5 will contain powders collected from each of the suspects. Students should

match the powders in Vial A to one or more of the other vials, and record their results.

Touching, tasting or feeling of the powders is not allowed, and may result in

disqualification.

Part B: Chromatograms Students will be asked to make chromatograms for up to 6 ink samples, and use these to help

identify the criminal(s). The chromatograms will be turned in with the answer sheet.

Part C: Prints Students will be asked to compare fingerprints, shoeprints and tire prints from the 5 suspects

to those found at the crime scene. Partial prints may be used.

Part D: Unspecified evidence Students will be given no more than 2 pieces of “unspecified” evidence recovered from the

crime scene that do not fall under any of the previous categories. This evidence will not

require any new skills, but will instead focus on students’ critical thinking skills. Examples of

unspecified evidence include but are not limited to: fiber samples, objects recovered from

scene, suspect statements, and handwriting samples. Ample instructions and assistance will

be given.

Part E: Criminal identification After all the evidence is collected, the students will identify the suspect(s) who committed the

crime. No more than 2 suspects will be implicated.

Scoring:

Students will earn points for:

Correctly identifying powders in each vial

Creating chromatogram

Matching of all evidence to the suspects

Identifying the criminal(s)

Any ties will be broken based on the fastest time to complete the test.

*Note: Povidone Iodine or a colored solution of Tincture of Iodine will work for practice

sessions. These can be purchased at many pharmacies. Decolorized Iodine will not work.