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Crime Busters

Students will evaluate crime scene evidence to determine who committed a crime. Students will be expected to test unknown powders, use paper chromatography to identify ink, match fingerprints, footprints, tire prints, and more.

Study Guides

Training Videos

FAQs

When we run a chromatography test, sometimes the ink does not migrate up the paper. What are we doing wrong?

You are not doing anything wrong.  Some inks are not soluble in alcohol.  It is possible that an ink sample like this could show up on a test.

Will students be pouring the rubbing alcohol in the cup for the chromatogrophy?

No.

The rubbing alcohol will already be poured into cup.

Who provides the pencil for Chromatography? Should the pencil be round or flat-sided?

Teams should bring their own pencil to suspend the chromatography paper.  It can be either round or flat-sided.

Is there any limit on the magnifying glass the students may bring?

Generally, no limit. 

The magnifying glass can have a light on it, but one is not required.
It can be any practical size, and there can be an additional magnification, such as having one magnification as the majority of the glass and having a smaller window of stronger magnification.

Microscopes are not allowed.

Must the 8.5" x 11" sheet of note paper that is allowed be typed, or does it have to be hand-written?

There is no requirement for the notes to be typed or hand-written.  Either will be acceptable.  It may have notes on both sides.

How many cups are the students given for testing liquids in the powders?

There will be at least 6 cups at each station, and students may ask for more if needed.

Will a team be marked lower if they identify 2 suspects as guilty if the correct answer is one of them, even if the evidence is correctly evaluated?

Points are awarded for identifying the correct suspect(s).  If innocent suspects are also named, a fraction of those points are taken off.

Are there any restrictions regarding the style, size, or power of the magnifying glass?

The magnifying glass must be one piece, and work without being plugged into an outlet.

How will the Chromatogram portion be scored?

A high-scoring chromatogram will have six neat designs that implicate the correct suspect(s) and travel straight up the paper running into each other.

If a student already wears glasses, do they still need to wear safety goggles?

Yes, splash-proof goggles which can fit over prescription glasses are required.  There should not be any gap between the goggles and the student's face. Goggles which look like glasses are not adequate.

Will the fingerprints be identified as from a right or left hand, or by the finger names?

The fingerprints may not be labeled.  Students should learn how to identify them.

Will students use rubbing alcohol to test the powders?

No.  Rubbing alcohol is used only for chromatography.

Will students be asked to identify the types of finger prints, e.g., arch, loop, whorl?

No.  However, it may be beneficial to mention this vocabulary when learning about fingerprints to make it easier to describe them.

How will students transfer powders to the paper? Will they have to pour it?

Students will be provided one plastic spoon for each cup.

Will fingerprints be presented as actual size?

Yes.  They will not be scaled.

Will the number of each part on the test match up with the numbers on the ZipGrade?

Yes.  

1 will be for the powders portion

2 will be for the chromatography

3-5 will be for the finger, foot, and tire prints respectively

6 will be for unspecified evidence

7 will be for final criminal implication.

May the students bring anything to help secure the chromatography paper at the proper height above the rubbing alcohol (tape, binder clip, etc.)?

No.  The students will be provided everything they need.  To see how this will look in the testing room, view the chromatography video we've posted.

If hair samples are used, would they be real hair or a photograph?

The students could be presented with either.  If they are physical samples, they will be presented as a microscope slide.  If they are photographs, they will be very magnified.

 

Are the liquids added to the powders on the black paper? Or are spot trays available?

Liquids should be added to the powders in the plastic cups.  Students will be provided spoons and extra empty cups to split up their samples and conduct tests on them.   The black paper is helpful for looking at dry powders up close.

Will the students be expected to write an essay to support their answer?

No.  The only written part is the identification of powders.

Can photographs be included on the notes page that each team may bring?

Yes, any information may be included, provided that it is printed or written directly on the page.

How will the ZipGrade form be used for recording the powders in each cup? Also, how will it apply to the other categories of evidence?

Powder identification is still written and hand scored as before.  Every "implication” question utilizes the ZipGrade, and will be labeled to match the form.  Students will be given a numbered list of very specific implication questions to avoid confusion.  For example, students might be asked which suspect(s) has the same powder(s) on them that were found at the crime scene.  Similarly, they could be asked which suspect's ink sample on the chromatogram matches the ink sample from the crime scene.

If more than one suspect matches a particular piece of evidence, how will students be able to answer multiple suspects on a ZipGrade form? Will the answers have predetermined specific combinations?

The ZipGrade scoring system has the ability to score multiple correct answers in the same question.  For example, if both B and D are correct matches, the student would be expected to mark both.  Students will be expected to select only the correct matches, and may lose points for answering incorrectly.

Should we expect multiple criminals to have the same matches in every section of the test?

They might or might not have the same matches.  Students should only implicate two criminals if they see two suspects with the same number of implications over all sections.

Is chalk the same as calcium carbonate?

Yes, however the calcium carbonate provided on the test will be in powder form and uncolored. Keep in mind that chalk may contain extra ingredients besides calcium carbonate.

Is Tums the same as calcium carbonate?

Tums contains calcium carbonate as the active ingredient, however it will likely contain extra ingredients that can interfere with reactions.

Where can I purchase calcium carbonate?

Powdered calcium carbonate is available in bulk from several sources on Amazon at a cheap price. We purchase it this way and it is classified as "food grade" which is 97% pure ground limestone.

You may also find it at some pharmacy stores in powder form, or you may have to buy it in tablet form and crush it.

Chalk can be a viable substitute if it is pure calcium carbonate.

For what reasons might a team lose points on the chromatogram portion of the test?

Students may lose points on chromatography quality and neatness of their test.  Perfect chromatography experiments will have straight ink lines from the wicking alcohol, and not over exposed (around 10 minutes is ideal) so the ink colors are nice and sharp looking.

Does each section carry the same amount of weight/points (example: each worth 25 Points) or does each section carry different percentage of the points?

Here is the approximate breakdown, this can change by up to 15%

Powder identification 40%
Chromatography 10%
Crime Analysis 50%

At the competition, how many grams of powder will be in a cup? How much water will teams be provided?

Cups will be filled with about 15 grams of powder total.  Teams will be given an excess of water, vinegar, and iodine.  Students should learn to only use drops of water, vinegar, and iodine when experimenting.

Might "unspecified evidence" include the subject of blood?

The test will be age appropriate.

For example, blood found at the crime scene could be from the criminal accidentally getting a paper cut while committing the crime. No blood spatter analysis or other information relating to violent crime will be included.  Students could be required to match characteristics of blood, such as blood types and DNA.

Will students be scored for naming all of the powders contained in each of the suspect containers? Or is the powder identification practice sheet just for their own use to aid in suspect identification?

Students will be scored on their ability to name all powders in all six cups.  There is a handwritten portion of the test for this, separate from the Scantron portion.

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Event Supervisor

Cathleen Saraza

Macomb Science Olympiad

P.O. Box 763, Sterling Heights, MI 48311

For questions about the Elementary division, contact This email address is being protected from spambots. You need JavaScript enabled to view it.