Back and forth, up and down. Swinging in a swing is almost like flying. What makes the swing go up in the air? Most of the time you do. You \"pump" with your legs and body. Sometimes you can get a...
Let’s Get Moving
Let’s Get Moving Let’s Get Moving
How Things Work
Here are explanations and experiments concerning forces and machines; sound, light, heat, motion, and electricity; the six simple machines; and such everyday machines as clocks, cam¬eras, and engines.
