Make Your Own Lava Lamp
Kids will love helping with this fun experiment. Fill a large, clear soda bottle three-quarters full with any type of vegetable oil; then top off with water. Ask your child to add enough drops of food coloring to cloud the water. Now, add the magic ingredient: a half tablet of Alka Seltzer. Watch the bubbles work up through the coloring. To get groovy, put a flashlight under the bottle in a dark room.