Choose several powdered substances. Sugar, salt, baking soda and pepper would be good choices. Decide which ones you think will dissolve and which will not dissolve. Use one clear plastic cup for each substance. Fill the cup 2/3 of the way full with water. Add a tablespoon of one substance to the first cup. Stir. Continue until you have added one tablespoon of each substance to a different cup, stirring each one. Note which ones dissolved and which did not.
Black is created by mixing colors. Separate them to find what colors are there after you guess which colors you will find. Cut two six-inch by two-inch strips from a paper towel. Four inches from the bottom, use two different brands of magic markers and draw a star. Place the ends of the strips in a bowl of water and let the other ends drape over the side. Make sure the marker ink is above the water. Watch as the water moves up the paper towel and separates the colors. Was your guess right?
What direction will roots grow when a plant is just sprouting? Decide and then do the experiment. Soak three beans in a wet paper towel overnight. Line the inside of a clear, plastic glass with a wet paper towel. Add more towel to the center to keep the wet towel against the sides of the cup. Put your three seeds between the cup and the paper towel. Keep them moist. Every five days, check the roots on the plant and keep a written record of what you see. What would happen if you turned the glass upside down?
Gather different types of soil, including sand, clay and humus. Have the tops cut off of three identical water bottles, leaving four inches on the top. Place a layer of cheesecloth over the mouth of the bottle and fasten it on with a rubber band. Put the bottles upside down in three identical jars. The jars should not touch the bottom of the jar. Add three inches of soil to each bottle, putting a different kind in each one. Slowly pour a half-cup of water into each bottle. Watch to see which soil allows the most water through.