# ENERGY KIDS

Energy tricks and experiments

In the air section you can find how to use science to perform magic tricks based on the energy properties and how to enhance any magic show.

These tricks and ideas can be used in any science projects or just for fun.

If you know any different tricks that would like to share with the other kids, you can contact us and we will make it possible.

Click on the list bellow to find how to perform it.

Why do the things fall down?

As you know all objects and things fall down and it's because of the gravity.

You can do a test by yourself.

All you need is to suspend various things from strings-a marble, a can, a fork, a toy and whatever you have. Youshould hold each up or tie it to a rod.

Start to cut each string one by one.

What you will see: The objects all fall.

Why: The force of gravity pulls objects down toward the center of the earth. This pull of gravity sometimes helps us and sometimes works against us. Gravity keeps us and everything around us from flying off into space, but it makes it harder for us to send a rocket to the moon. Compare how much easier it is to walk down a flight of stairs than it is to walk up a flight. When we climb and when we lift something we need to make the upward pull or push greater than the downward pull of the earth.

Which falls faster

Did you manage to see which object fall faster when you gut the strig? No?

So try to do this:

You need a sturly table or a high chair and 2 objects - a heavy and a light one.

Stand on a sturdy table or on a high chair and drop the two objects you alreday have at the same time - a heavy object and a light one.

What you will see: Both objects reach the ground at the same time.

Why: The weight of an object does not affect its speed as it falls.

But we know that a feather doesn't fall as fast as a stone and that a man with a parachute falls more slowly than a man without one. So what is the difference? Is it a magic?

No. The shape of the feather and the parachute are important because they offer a larger surface to the air and are slowed down by the air's resistance.

Sprinklers and rockets
You need: a hammer, a small nail, an empty can, piece of wire.

How to:
Step 1: Using the hammer and the nail, make 4 small holes near the bottom of the can. The holes should be in a straight line about inch apart.
Step 2: Run wire around the rim of the top of the can.
Step 3: Hang the wire from a piece of string, and then tie the string to a hanger and support it on a ledge or rod.
Step 4: Pour water into the can.

What you will see: The water goes out the holes in one direction-and the can swings in the opposite direction.

Why: Maybe you know that for every action, there is an equal opposite reaction. As the water rushes out forward it causes the can to move backward. Revolving lawn sprinklers work in much the same way. When you row a boat, the oars push the water backward and the boat moves forward.

Do you know what will happen if you blow up a balloon and then let go of it?
Try to explain why.

Center of gravity

You need: a ball, a level surface, some clay.

How to:
Step 1: Roll a ball on a level surface. Do it several times and notice what happens.
Step 2: Stick some clay on the ball at one point. Roll the ball again. Repeat it a few times. Can you see the difference?

What you will see: At first the ball keeps on rolling and stops in any position. When the clay is fixed to one point, the ball always stops rolling with the clay touching the surface on which the ball is rolled.

Why: The ball acts as though all of its weight is concentrated at one point. This is known as its center of gravity. It is likely to be located at the part where most of the weight is.
Any object will tend to move until its center of gravity is at its lowest possible point.
The center of gravity of the ball is at its very center. It is balanced at any point since rolling neither raises nor lowers its center of gravity. When we put on the clay, however, the center of gravity is changed and the ball will tend to roll until the clay is at its lowest possible point.

Stop and go

You need: a toy vagon, some blocks.

Step 1: Fill a toy wagon with blocks.
Step 2: Start it slowly, pull it for a time, then slowly stop it.
Step 3: Atart the wagon quickly, pull it for a time, and stop it quickly.

What happen?

You will see: It is harder to start the wagon than to keep it moving. The quicker you want to start it, the harder you need to pull. The faster it is moving, the more energy you need to stop it. Also, the more quickly you want to stop it, the more force you need.

Why: It takes more force (push or pull) to start and to stop an object than to keep it moving. Objects that are moving tend to keep moving, and objects at rest tend to remain at rest. This is known as inertia.

Wheels

You need: a oil drum (s,al barrel)

Step 1: Place the barrel in an upright position and push it across the room.
Step 2: Turn the barrel on its side and roll it back.

What happen: It is much easier to roll, than to push the can.

Why: There is less rolling friction than sliding friction. In sliding, the bumps on the rough surfaces catch against each other. In rolling, the bumps of the wheel roll over the bumps of the rough surface without rubbing as much.