Students can explore concepts of density and chemical reactions by making raisins "swim." Fill a glass gar ¼ full of vinegar and ¾ full of water. Add baking soda and stir. Drop in a few raisins and observe. The carbon dioxide bubbles will carry the raisins to the top of the jar. Raisins will sink again when they lose the support of the bubbles, because the raisins are denser than the water.
Students can also explore the chemical reaction of baking soda and vinegar by creating a film canister rocket. Pack the lid of a film canister tightly with baking soda. Pour two tablespoons of vinegar into the canister. Put the lid on carefully, turn the canister upside down on the ground and stand back. The canister should shoot into the air.
Students can create a tongue map project in one day. Start by drawing a diagram of the tongue. Students should use a cotton swab to spread lemon juice around their tongues and use the diagram to record where they sense the sour taste. Repeat with sugar water, salt and instant coffee.
Students can also create a model of the human eye. Poke a small hole in the bottom of a paper cup. Use a rubber band to attach a piece of wax paper over the top of the cup. Point the bottom of the cup at a light bulb from two feet away. Move slowly toward the light. Students will see an upside down image of the light bulb on the wax paper, which models how the human eye sees images.
Chromatography projects separate ink into its component chemicals. Have students draw a picture on blotting paper using different colors of felt-tip pens. Dip the edge of the paper into water, and let it set for a few minutes. As the paper soaks up the water, the different chemicals travel at different speeds, and ink patterns should emerge.
In a similar project, have students dip M&Ms or other candy coated chocolate into water, and then dab them on blotting paper. Water based paints and different types of black pens can be tested in the same way.
Students can produce carbon dioxide gas in a glass bottle with a cork. Make a hole in the middle of the cork with a skewer. Put a flexible drinking straw into the hole. Fit another drinking straw into the end of the first straw. Fill a glass with water and food coloring, and insert the end of the second straw into the glass. Put 1/2 tablespoon of baking soda into the glass bottle, pour vinegar into the bottle until it is ¼ full, and cork the bottle. The baking soda and vinegar will react and create carbon dioxide gas, which will travel through the straw and make the water in the glass bubble.
Another project demonstrates how gases contract when they get cooler. Each student should fill a glass bottle with warm water and let it sit for a few minutes. Pour out the water. Cut the narrow portion off a balloon, and cover the bottle's mouth. Put the bottle in a bowl of cold water. The balloon will inflate inside the bottle because as the air inside the bottle cools, it contracts, and the air outside the bottle will push the balloon in.