- Forensic scientists often use fingerprints to determine who committed a crime.fingerprints image by dip from Fotolia.com
Law enforcement officers must often figure out what happened at a crime scene based only on items found, including footprints, fibers from clothing and drops of blood. Forensic scientists have the job of piecing together these bits of evidence and figuring out what happened as well as who committed the crime. Kids may enjoy playing the part of a crime scene investigator with some forensic science activities. - As part of their investigations, forensic scientists sometimes have to determine how long a deceased body has been at the crime scene. At the University of Tennessee, forensic researchers have a "body farm" where more than 40 bodies are kept on the ground while researchers record the bodies at different stages of decay. They observe the way human bodies decay in response to weather conditions and animal encounters. While you won't be able to use a cadaver, your students can observe the decaying process of an apple and record what it looks like in various stages of decay. Each day, you can take photographs of the apple and at the end of two weeks, you can provide students with pictures of apples at different stages of decay and see if they can pinpoint the approximate number of days the apple in your pictures have been decaying based on the observations they recorded.
- Forensic scientists need to collect any evidence they possibly can from the crime scene to help them resolve the crime, such as hair samples, DNA samples and fingerprints. For this activity from Discovery Education, you'll need to choose a student to be the perpetrator and make sure that person won't tell the others that she "committed the crime." Collect a hair sample and thumbprint (you can use an ink pad and an index card). Tell the class that someone committed a crime in the classroom and the only evidence you have is what you've collected, so until you can eliminate individuals, everyone is a suspect. Have each student -- including the perpetrator -- collect a sample of his or her own hair and thumbprint, and then put the items in a bag. You can then have the students work together to figure out who your "evidence" belongs to by looking at the samples provided by each student and comparing those with the evidence.
- Fingerprints may be the only piece of evidence left behind at a crime scene, so it's important that forensic scientists know how to pick them up from almost any surface. In this activity from Criminology Degree, kids can practice lifting fingerprints. You can put your students in groups of 5 to 6, and then provide each group with 1/4 cup each of talc powder (for dark surfaces) and cocoa powder (for light surfaces). Groups will sprinkle a small amount of the powder on a surface, and then use a blush brush to dust the powder away, leaving behind a fingerprint. To lift the fingerprint, students will press a piece of clear tape on the powdered fingerprint, and then push down on the tape before slowly peeling back the tape.
