Opening doors, playing baseball, running a race, practicing for a school play---you really keep moving. How does your body keep going? What makes you move? You keep moving in almost the same way a...
Full of Energy
Full of Energy Full of Energy
What keeps them up?
How do an airplane's wings help it stay in the air? What keeps a satellite up? Airplane wings have a special shape. They are curved on top and straight on the bottom. This shape is what helps lift...
A push in two directions
Blowing up a balloon takes a lot of huffing and puffing. But if you let the balloon go, the air rushes out---and the balloon takes off like a rocket! What makes it fly? When you blow up a balloon,...
A tug from the earth
Imagine floating through the air, standing on the ceiling, or leaping upstairs in one big bound! An astronaut traveling through space can do all of these things. But on the earth, you can't. You...
A force that pushes and pulls
Magnets can do strange things---that's what makes them such fun to play with. They can stick to each other. They can make nails or pins hang on to each other, like people holding hands. They can even...
A machine that never stops?
For twenty-seven years Dr. Coatsworthy Mothbold has been building an automatic polka-dotting machine. It can paint polka dots on anything---walls and windows, shirts and socks, even pretzels and...
Friction from air
Even air creates friction---it rubs against moving things and slows them down. You can make a \"helicopter" that uses the friction of air to slow its fall---and to spin, too. Place the paper with...
How do brakes work?
> This bicycle has hand brakes---one for the front wheel and one for the > rear wheel. To stop, the rider squeezes the levers on the handle bars. Slow down! There's a busy street ahead. Stop your...
The invisible push
The light turns green and the car starts to move quickly. It feels as if a big, invisible hand pushes you back in the car seat and makes you stay there. But it feels different when the car stops...
