Using fingerprints to solve mysteries

Imagine that one day you got a new toy. The next day, the toy disappeared. A few days later, you find it in the closet of a sibling you trust. How can you find out if the sibling has or hasn't taken the toy? You can use fingerprints to figure this out. You will need: a paintbrush, cocoa powder, a piece of paper, tape, and a pencil.

First, you will need to collect the fingerprints of all your family members, including yourself. To collect a fingerprint, ask a family member to put their finger on a flat surface, such as a table. When he/she takes their finger off the surface, spread cocoa powder on the area where he/she touched. Lightly brush it off with the paintbrush. You should be able to see the fingerprint. Put a piece of tape on it, then gently peal it off. The fingerprint should come off with it. Put the tape on the piece of paper, and write the family member's name above it.

Next, you have to collect fingerprints from your toy. Spread cocoa powder on the surface of your toy and gently brush it off with the paintbrush. You should be able to see fingerprints on it. Put tape on a fingerprint and gently peal it off. The fingerprint should come off with it. (Don't collect any of your own fingerprints.)

Next, try to find a match to the fingerprint in the fingerprints of your family members (using a magnifying glass). As soon as you find the match, look above the matching fingerprint to see which family member it belongs to. That family member is the culprit.