Call it the Ewww! Factor, but nothing engages kids in science more than a down and dirty hands-on project. Inspire your class and reinforce science concepts with these icky, creepy, smelly, and gross experiments.

Warning: Do them after lunch!
Boogers and Body Parts
Snot Now
What it teaches: One way the body fights off bacteria and filters the air we breathe; measuring
What to do: Have each student dissolve 1/8 cup of borax in two cups of warm water. In another container, have students stir together two teaspoons of glue gel and three teaspoons of water. (White glue will work too, but the gel makes the snot more slimy.) Add a few drops of green and yellow food dye and stir. Pour mixtures into a baggie, seal, and then squish the mixtures together. Remove snot from baggie. After the kids are done playing with the snot, have them blow dust across the surface of it. This will show how nasal mucus filters air debris and makes boogers. Remind the students they should wash their hands after handling any kind of snot—real or fake!

Edible Model of Skin
What it teaches: The layers of skin
What to do: As a class, pour a layer of miniature marshmallows in a large, shallow dish. This will be the subcutaneous layer of the skin, which is made mostly from fat. Next, pour red-colored gelatin over the marshmallows. This will become the dermis, or inside layer of skin, which is full of blood vessels and nerve endings. After the gelatin has set, add a layer of fruit leather to serve as the epidermis, the protective, outer layer of skin. Add hair by cutting short pieces of black licorice strings and poking them into the fruit leather. (Tip: Poke a hole through the fruit leather first using a toothpick.) Add chocolate chips for moles or dehydrated strawberries for scabs. Yuck! (Or should that be “yum”?)

Fart Journal
What it teaches: Observation skills; how certain foods affect our bodies
What to do: Have students keep a journal of how many times they pass gas for one week. (Any kind of flatulence counts.) Collect the data in a slotted box to maintain privacy. As a class, calculate how many times, on average, they pass gas in a single day. Next, ask students to eat beans or another food, such as broccoli, that produces gas. Have students keep track of their flatulence for another day or two to see if beans really are “the musical fruit.”

Super Spit
What it teaches: The importance of saliva in tasting food
What to do: Have students use paper towels to dry off their tongues. Next, have them taste a variety of dry foods, such as crackers, pretzels, and bagels, one at a time. Ask them to record their observations. Next, have the students take a drink or two of water. This will help stimulate saliva production. Have them try the foods again and record their findings. Chemicals in the food will dissolve in the saliva and should trigger receptors on the taste buds.

Gross Germs
Grow a Germ Garden
What it teaches: Making predictions; the fact that germs are everywhere even though we can’t always see them; the physical characteristics of mold
What to do: Ask students to predict which surfaces in the classroom are the dirtiest. To test their predictions, have them put on rubber gloves and gently rub slices of white bread on those surfaces as well as surfaces that appear clean. (Bread without preservatives works best.) Place each slice of bread in a baggie that’s been marked with the location. Sprinkle each slice with one teaspoon of water and seal the baggies. Place them in a sunny area. All the bread will grow mold, but some mold will grow faster or look more disgusting. To prevent possible allergic reactions, do not open the baggies at any time.

Have Germs, Will Travel
What it teaches: How germs are spread through physical contact
What to do: Have students sit in a circle while you rub a piece of sidewalk chalk all over your hands. (Inexpensive, colored chalk works best for this experiment because it creates more dust.) The dust represents germs. Once your hands are covered in chalk, begin walking around the circle, shaking hands randomly. See how many students catch the “germs.” Variation: Invite each student to cover his or her hands in chalk dust. Next, have students sit at their desks and do a simple task. After they have seen firsthand (pun intended!) just how easily germs can be transferred, have them clean their space and wash up.

Big Book of Viruses
What it teaches: The scientific names of common viruses and microbes;
writing; illustrating text
What to do: Have individual students or teams of students create a short tongue-in-cheek biography for a variety of viruses and microbes [for example: salmonella, E. coli, rhinovirus (common cold), orthomyxovirus (flu), and streptococcus (strep throat)]. Ask students to include the virus’s name, nickname, favorite hiding place, symptoms it inflicts, hobbies, friends, and enemies. After looking at real photos for inspiration, have students draw a picture of their virus to complete the biography. Gather the bios into a class book.

Creepy Crawlies
Musical Chairs, Roach Style
What it teaches: The term nocturnal
What to do: Find a large, open area to run around in and enough carpet squares for each student. Be sure the area has overhead lighting. Scatter the carpet squares all over the ground. These squares are the roaches’ “hiding places.” Have the students stand on the carpet squares. Turn off the lights. Students should move around the room like roaches would at night. While students are moving, remove one of the carpet squares. When the lights go on, the students need to find an open square to stand on. Keep turning on and off the lights and removing squares. Play continues until only one “roach” is left. Pair with Janell Cannon’s Crickwing, a terrific cockroach picture book.

Worm Farm
What it teaches: Observation skills; animal habitats; recycling
What to do: Cut off the top quarter of a two-liter plastic bottle. Poke several air holes near the bottle cap. Set aside. Next, poke drainage holes in the remaining piece of bottle. Place the bottle on a shallow dish. Shred several pieces of newspaper into a bowl. Add two to three cups of soil and one cup of water and combine until the mixture is damp but not dripping. Place this inside the bottle. Add six to 12 earthworms and tape the top back on. Place the bottle in a dark, room-temperature place. In a few days, you’ll be able to see the worms’ tunnels. Feed the worms small bits of grass or pieces of fruits or vegetables. Keep the soil moist. After a few weeks, be sure to set your worms free!

Drinkable Blood
What it teaches: The color and consistency of human blood
What to do: After reading about ticks, leeches, lice, and other blood suckers, top off the unit with this concoction. Each student needs a plastic cup and a spoon. Have students pour 1/3 cup of water into the container. Next, add one teaspoon of chocolate syrup, three teaspoons of light corn syrup, and five to eight drops of red food coloring. Mix well. To add a little morbid fun, pour the “blood” into baggies and label with the students’ names and blood type and chill before drinking.

Super Stinky
Smell Ya Later
What it teaches: Distance; division; how smells travel in the air
What to do: Place a variety of smelly foods or objects in individual containers with lids at one end of the classroom. These items might include microwave popcorn, perfume-soaked cotton balls, onions, or strong spices. Have a volunteer sit or stand at the other end of the classroom, 20 feet away. Open the containers one at a time, and use a stopwatch to find out how long it takes before the volunteer first smells the item. Between opening the different containers, run a fan for a few minutes to clear the air. Divide 20 by the number of seconds it took to smell the item to determine how many feet the smell traveled per second.

Match That Scat Memory Game
What it teaches: The term scatology; memory skills
What to do: Set up a scat center in your classroom. Include books from the “Who Pooped in the Park?” series by Gary D. Robson, owl pellets and tools for dissecting them, and a “Match that Scat” memory game. To create the game, draw a dozen animals on index cards and pictures of their scat on a separate set of cards. (For examples of scat, try / scatanswers.htm or a scat guide.) If you don’t mind the giggles, you can also have students design the game themselves. Variation: Create an interactive bulletin board where students match up animals to their droppings.

Got Spoiled Milk?
What it teaches: Observation skills; how temperature affects spoilage
What to do: Pour one cup of milk in each of three, clean containers with lids. Seal the lids with tape to make sure the specimens are not disturbed for the duration of the experiment. Place one container in the refrigerator. Place the second container on a shelf that’s away from any heat source. Place the last container on a sunny windowsill. Wait one week, open the containers, and observe. (For health reasons do not touch the spoiled milk.) Variation: Place one cup of whole milk in a clean container and one cup of skim milk in another clean container. Leave both on a windowsill. Which one goes bad first? Does the lactose content make a difference?
Just Plain Weird
They Eat What?!
What it teaches: Cultures and foods from around the world
What to do: Read Disgusting Foods by Connie Miller, or It’s Disgusting and We Ate It by James Solheim. Next, hold a pretend Weird Foods Around the World Tasting Party. Have the students bring in kid-friendly versions of strange foods from around the world. For example, students might bring in pot roast for dog meat (Indonesia), cooked brown rice or orzo pasta for ant larvae (Thailand), chocolate-covered fried noodles for spiders (Cambodia), broth with shredded wheat for bird’s nest soup (China), apple butter for Vegemite (Australia), gummy worms or scorpions on a stick for insects (China).

Bird Poop Painting
What it teaches: The diet of different kinds of birds; research skills
What to do: Students should put about 1/4 cup of white tempera paint into a squeezable condiment bottle. Have students choose a bird and research its diet. Add crushed berries, seeds, nuts, and other bits of foods that would be appropriate for the poop they’re making. Put the lid on the bottle and shake to mix. Spread the work area with newspaper and place a large piece of black construction paper on top of the newspaper. Have students stand above the paper and squeeze the condiment bottle until a plop of paint poop comes out. If the paint mixture is too thick, add a bit of water or cut a bigger hole in the condiment bottle lid. After the paintings dry, write the name of the bird on them and display. Instead of pop art, think of it as poop art!

Fish Mummy
What it teaches: The process of mummification; characteristics of sodium bicarbonate and salt; observation skills; dehydration
What to do: Ask a butcher or fisherman for a fresh fish that’s been cleaned. Fill the fish’s stomach cavity with equal parts of baking soda (sodium bicarbonate) and salt. Fill a plastic container with three inches of the baking soda/salt mixture and place the fish inside. Next, cover the fish with about three inches of the baking soda/salt mixture. Place in a dry location and don’t disturb. After one week, replace all the old baking soda and salt with fresh baking soda and salt. Leave the fish undisturbed for another week. Remove baking soda and observe what has happened. It’s a fish done pharaoh-style!

Rubber Egg
What it teaches: Chemical reactions; parts of an egg; observation skills
What to do: Place a raw egg into a glass jar and cover with white vinegar. Place a lid on the jar and let the egg and vinegar sit for a day. The next day, pour out the vinegar and add fresh vinegar to the jar. Seal again and don’t disturb for one week. Then, pour out the vinegar and carefully rinse the egg under cold water. The egg’s shell should be gone, worn away from the vinegar’s acid. (Note: Do not eat the egg—not that you’d have any interest!) Variation: Follow the directions above, only use a hard-boiled egg. The egg will bounce.