Not allowed to do that anymore. Anyone handling human blood has to take “Bloodborne Pathogens” course and have proper disposal of sharps and waste. They have “faux” blood type test kits that you can buy. It comes with various vials of fake blood of different blood types and all the reagents needed to test the fake blood for blood type.
Fisher Scientific has a Science Education section on its website. Use that for some ideas.
More deliciously slimy than either of these is Polyvinyl Alcohol and Borax. if you color it green, it makes a great “snot”
http://chem.lapeer.org/Chem1Docs/SlimeDemo.html
http://education.andrew.cmu.edu/gelfand/scimodules/4._Polyvinyl_alcohol_Slime.html
www.chymist.com/PVA%20Slime.pdf
And it goes in GLOW in the Dark:
You will need:
Moisten Q-tips with oil, then swab the cat’s ears VERY gently. Roll a little of the blackish goo onto the microscope slides
Look at the ear mites under the scope - they will be alive and will be crawling around. They will also look HUGE under the scope.
Remind the class that they’d just spent the last 20 minutes petting the cat. Kissing it on the head is even better.
The primary ingredient in Elmer’s glue (perhaps other than water) is polyvinyl acetate…it works just as well and is easier to obtain. I’ve made literally gallons of this stuff for chemistry fairs and my mom’s classroom. Any white glue will do, really.
If you mean “just as well as polyvinyl alcohol”, I’ll have to disagree. the textures are very different (and if you color elmer’s glue slime green, it looks like green elmer’s glue, not the vibrant transparent green of polyvinyl alcohol slime.
It’s more trouble to get polyvinyl alcohol, but it’s worth it.
It’s true that it won’t be transparent, but I found that the texture can be varied quite a bit with different concentrations of the glue and Borax. I have done the polyvinyl alcohol version as well, and I don’t remember it being that different, though I admit it’s been several years (OMG probably a decade :eek:)
I made a ton of the glue+borax one 2 years ago for my mom’s grade 1/2 classes (the whole year)…then for a grade 4 class whose teacher dropped by and got curious, leading to a grade 3 class asking for a turn, then I think the other 4th graders…that’s about when I ran out of ingredients. The dixie cups were replaced by looseleaf folded into paper cones, and no one cared for stirring sticks anymore even if there were any left. Kids really love this stuff, because they love watching the transition from liquids to goo, as well as just playing with it.
In my experience the Glue and Borax came out more Silly Putty-like, while the PVA and Borax came out more like slime. But i haven’t played extensively with concentrations.
I’ll second composting, and add that worm composting would be great for kids. There’s not a lot of digging involved and the kids can feed the worms with their fruit and veggie scraps. You can tie it in with worm anatomy, the cycle of life (the compost is worm poo), ecology, and even nutrition. The cost isn’t very high, around $30 for a pound of worms + ten pounds of dirt and maybe $5-6 for a large plastic bin. There’s a lot of lesson plans online.
I volunteered at an after school program for a while and did worm composting with the kids and it’s a lot of fun. The kids are very grossed out by the worms but they love feeding them their leftover scraps. If you start the compost pile at the beginning of the summer, you might even be able to use it to start some seeds for the kids.
Dopers, I’m in between wrangling Boy 1 and Boy 2’s bath and bedtime, but wanted to at least say: You guys are awesome. 
I read one recently about “The Importance of Washing Your Hands”.
Materials: potatoes, potato peeler, knife, Ziploc bags, soap and water.
Preparation: peel the potatoes, wash them well, cut them into chunks, and store them in a bowl filled with clean, room-temperature water.
For the next bit, you’ll want to divide the kids into groups. One group will not wash their hands, one will rinse their hands briefly under cold water, and the other will wash vigorously with soap and warm water. When all the kids are ready, use a clean tool such as a fork to pick a potato chunk out of the water and place it in each kid’s hands (careful not to contaminate it with your own hands). Have the kids handle them for a while and rub their hands all over them, then have them place each chunk in a separate Ziploc bag. Have them write their name, date, and whether their hands were unwashed, rinsed, or thoroughly washed on the bag. Hang the bags up somewhere that everyone can see.
Check on the contents every few days. You should see a lot more exciting growth on the potatoes that were handled with unwashed hands.
While working the cat over, stick your pinky in your ear and get your own earwax on it. Then show the pinky to the cat. The cat will probably eagerly lick your finger. Why would the cat evolve to like ear wax? Is it to encourage them to lick each other’s ears to help combat the mites?
Just a thought, here - don’t fool with the cat’s ears and then stick your dirty finger in your own ear - that is, unless you want to experimentally determine what having ear mites feels like.
Are there any ranches in the area? My grade 9 science teacher had a hobby farm and brought in a full sheep head to show off the brain. He also brought in the organs, blew into the lungs so we could see them expand, and squeezed out the intestines.
I was torn between being grossed out or awestruck.
How about cooking with insects? You could grow some mealworms in class and then have a delicious snack.
These cayenne pepper mealworms sound pretty delicious.
Forget ranches - you can order all that if it isn’t handy!
If you want to cook with insects, let me recommend this book (as I have in the insect-eating thread), Davif George Gordon’s Eat-a-Bug Cookbook:
Heck, just reading from this book is arguably gross enough.
I saw them do this at the Dupont pavilion at the 1964-65 World’s Fair and was amazed – they made it in a martini glass. I wanted to do that. For years you couldn’t find the “recipe”, but lately I’ve seen it springing up in various places.
It looks fun, but I wouldn’t let kids do it – they’d have to watch. Whereas you can actually eat many of the “goop” and “slime” recipes above.