Learn about the laws of motions with a roller coaster experiment. Purchase foam tubes from a hardware store that are sold for pipe insulation. Cut the tubing in half lengthwise so you can use it as a marble track. Tape the foam tubes to a wall with masking tape into a roller coaster design. Experiment with the hills and turns. Ask your child what factors may affect the speed of the marble and how they can create enough speed for the marble to stay in a coaster loop.
Learn about the physics of vortexes in weather patterns, such as tornadoes, at home. Create a vortex in a bottle with two plastic soda bottles, a washer and duct tape. Fill one bottle two-thirds full with water. Place the washer over the opening of this bottle. Add some food coloring to the water. Tape the second bottle to the first bottle so the two openings meet. The second bottle should be upside down. Turn over the bottle with water while swirling it. As the water enters the empty bottle, a vortex should appear.
Learn about the physics of sound with a simple telephone experiment using two paper cups and string. Tie toothpicks the ends of a long piece of string, about 6 feet long. Poke each toothpick into a paper cup and push the toothpicks into the holes. Pull on the string so the toothpicks are secure inside the cups. Pull the paper cups on the string taut and have one child speak into a cup while you listen in the other cup. Then switch roles; you speak while the child listens. The sound waves should travel along the string while it is taut. Then test the telephone when the string is not taut.
Create a pinhole camera for a physics experiment about light. Use an old cereal box or oatmeal container. Cut 2 inches from the bottom of the box so that the entire box is reduced by 2 inches. Cover the opening of the small, cut portion with wax paper and secure with tape. Tape together the two cut pieces of the box. Cover the entire box with foil so that light cannot enter it. Tap a hole into the middle of the bottom of the box with a thumbtack. Take the box outside; you should be able to see images upside down on your wax screen when looking into the open top of the box.