11. Invisible Ink
Anne Helmenstine
Invisible inks either react with another chemical to become visible or else weaken the structure of the paper so the message appears if you hold it over a heat source. We're not talking about fire here. The heat of a normal light bulb is all that's required to darken the lettering. This baking soda recipe is nice because if you don't want to use a light bulb to reveal the message, you can just swab the paper with grape juice instead.
12. Bouncing Ball
Polymer balls are a variation on the slime recipe. These instructions describe how to make the ball and then go on to explain how you can alter the recipe to change the characteristics of the ball.13. Iron from Cereal
It doesn't have to be cereal. What you need is an iron-fortified food and a magnet. Remember, iron is actually toxic so you won't pull huge quantities out of food. The best way to see the iron is to use the magnet to stir the food, rinse it with water, then wipe it with a white paper towel or napkin to see the tiny black filings.14. Candy Chromatography
Anne Helmenstine
Examine the pigments in colored candies (or food coloring or marker ink) using a coffee filter and a salt water solution.
15. Recycle Paper
Anne Helmenstine
It's easy to recycle used paper to make beautiful cardstock for cards or other crafts. This project is a good way to learn about papermaking and recycling.
16. Vinegar & Baking Soda Foam Fight
The foam fight is a natural extension of the baking soda volcano. It's a lot of fun, and a little messy, but easy to clean up as long as you don't add food coloring to the foam.17. Alum Crystals
Anne Helmenstine
Alum is sold with pickling spices in the grocery store. Alum crystals are among the quickest, easiest, and most reliable crystals you can grow so they are a great choice for kids.
18. Rubber Egg & Rubber Chicken Bones
Anne Helmenstine
The magic ingredient for this fun kid's chemistry project is vinegar. You can make chicken bones flexible, as if they were made of rubber. If you soak a hard-boiled or raw egg in vinegar, the eggshell will dissolve and you'll be left with a rubbery egg. You can even bounce the egg like a ball.
19. Ivory Soap in the Microwave
Anne Helmenstine
This project will leave your kitchen smelly soapy, which could be good or bad, depending on your opinion of the Ivory soap fragrance. The soap bubbles up in the microwave, sort of resembling shaving cream. You can still use the soap, too.
20. Egg in a Bottle
Anne Helmenstine
If you set a hard-boiled egg on top of an open glass bottle it just sits there, looking pretty. You can apply science to get the egg to fall into the bottle.
