Forensics is a topic students LOVE to learn about, so even if you don't teach an entire course on it, throwing in a few lessons at the end of the semester is always fun. There are a ton of labs you can do ranging from blood spatter, fingerprinting, analyzing hair and fibers and impression evidence. There are a bunch of free lab downloads at The Science Spot's website (especially great for middle school grades).

Last year I wanted to add entomology to my forensics unit. I could have ordered maggots online, but if your school is anything like mine, you place an order and cross your fingers it arrives within the next 4 months. Since I didn't plan ahead that well, I needed them within the next week.

If you want to get your own maggots growing, it's not difficult to do. All you need are the right environmental conditions. Flies like to lay their eggs in dark warm places (like inside of a decomposing body....). The easiest way to replicate these conditions is to buy a rotisserie chicken at the grocery store, eat some chicken for dinner, and save the carcass. Check out the video below with more details and how you can use them with your students.

When we learned about entomology I had students read this article I wrote up on Body Farms. If you aren't familiar with body farms, they are outdoor research labs where donated bodies are left do decompose in different scenarios and conditions. Scientists use this information to help determine estimated times of death. It's a little gross, but fascinating.

Have any questions I didn't answer in the video? Leave them in the comments and I'll get back to you!

Ordering class sets of prepared slides can be pricey. Want a fun and free way to make your own? All you need are some slides, clear tape, and some animal hair samples. Put a few pieces of hair on a slide and carefully cover it with clear tape. A couple tips:

• Don't use scotch tape that has a matte finish or you won't see it very well under the microscope. Make sure it is clear cellophane tape. 
• Be careful to not leave fingerprints on the tape when handling. 
• Lighter hair samples are easier to see under the microscope than darker hair samples. If you have the option, go lighter. 
  
• With the taped slides, you will get small air bubbles. Make sure to warn the students first, so they don't end up drawing air bubbles on their lab paper instead of hair (because you know a few will!)
  
• I have read online that instead of using tape you can use a cover slip and a dab of super glue or clear nail polish. For me tape was easier, so that's what I went with. 

When you look at the hair under the microscope you will see that different species have varying medulla patterns in the center of the hair.  I gave my students a couple of samples to look at- human, dog, and cat, and then gave them an "unknown" slide and had them figure out which type of hair they were looking at. If you have students with some fun pets at home (such as a rabbit, ferret, or guinea pig) ask them to bring in a few hairs as well.
(Below: Left image is human hair, Right image is cat hair)

Another way to get some unusual hair samples is by checking with your local game and fish department. In Arizona our Game and Fish department has skull and pelt boxes that they loan to schools for free. I had borrowed the skull box for my ecology unit and had my students compare skulls of different animals. While I had the box, I also plucked a hair or two off the pelts and made prepared slides. It was fun to look at mountain lion, bear, and coyote hair in addition to the everyday pets.  

Have you made prepared slides for specimens other than hair? I'd love to hear about it! Leave it in the comments!