You will need: six wooden toothpicks, small saucer, and water.
1. Bend five toothpicks into V shapes.
2. Place toothpicks within a one-inch circle on saucer. Bent ends should point toward center of circle. Wet the sixth toothpick and drop water from it onto each bend of the five toothpicks.
3. Notice how when dry wood becomes wet, it expands—the wet toothpicks straighten and move apart to form a star.
Why do soap and water clean so much better than just plain water? Do this experiment and you will find out why.
You will need: Two small jars with tight lids, cooking oil, water, and powdered or liquid soap.
1. Pour 2″ of water and 1″ of cooking oil into each jar.
2. Add 1/2 teaspoon soap to one jar.
3. Close jars tightly and shake.
4. Notice how in both jars the oil has broken up into small droplets. But in the jar without soap, the oil quickly floats to the top because water and oil do not mix. However, the oil in the jar containing the soap does not go to the top, because the soap acts as an emulsifier and keeps the oil droplets dispersed in the mixture.