You can teach lessons about sound, speed, the states of matter, and other concepts.

• Gather a rubber balloon, a long-necked bottle, baking soda, and vinegar. Pour some vinegar into the bottle. Then put about two teaspoons of baking soda into the balloon. Stretch the opening of the balloon over the mouth of the bottle. Your child will be delighted to see that the balloon inflates. The baking soda and vinegar mix to form a gas.

• Use blocks, small boards and small balls to teach about the way things pick up speed. With the blocks, build two towers. Make a small one and a large one. Now lean the boards against the towers so you have two ramps. Have your child roll the ball down each ramp. Have him note where each ball ends up. Ask him what he observed. Talk about the fact that objects will fall faster from steeper and higher heights.

• Go outside and pick up two rocks. Ask your child to rub them together as hard as she can. Now have her carefully touch one. The heat she feels is called friction.