? WHAT IS A FORCE ?

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Simply put, a force is any push or pull!

Every time you push or pull with your muscles to open a drawer, kick a ball, swim, or do exercises, you are using a force.

But a force does not always cause motion.

For Example:

A person who tries to open a drawer that is stuck is exerting force even though he or she may be unable to move the drawer.

More: There are many other kinds of forces besides those exerted by your muscles.

Some of these forces exist in a very small particle known as an atom. Others are exerted by magnets and electricity.

! LETS EXPERIMENT !

HERE ARE THE DIFFERENT FORCES:

( Point and click on the force you wish to experiment with.)

GRAVITY: The force that pulls everything to the center of the earth.

BUOYANCY: The force put on an object by a liquid.

COMPRESSION: The force that pushes objects together.

TENSION: The force on an object when you stretch it.(the opposite of compression)

FRICTION: The force when one object moves over another, creating heat.

MAGNETIC FORCE: The force of attraction or repulsion, due to magnetic poles.

ELECTRIC FORCE: The force of attraction or repulsion due to the movement of electrons.

ELASTIC FORCE: The force that results in an object being stretched.

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! HERE WE GO !

"MAY THE FORCE BE WITH YOU" !

GRAVITY:

MATERIALS: 1 brick, 1 board, a comb, and an elastic band.

PROCEDURE: Lift various objects with your hand. Notice which objects feel the heaviest and which feel the lightest. (THE FORCE ACTING ON THESE OBJECTS IS CALLED GRAVITY.)

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BUOYANCY:

MATERIALS: Modelling clay and a mid-size bowl and water.

PROCEDURE: Fill the bowl approximately half full with water. Mold the modelling clay in the shape of a canoe (sides up with a deep hull.) Place the clay onto the surface of the water and observe the effect. Notice that the clay stays afloat. (THE FORCE ACTING ON THE CLAY IS BUOYANCY.) Now try and sink the clay by pushing it under the water line. Notice that once the hull has filled with water and displaced the buoyancy effect of the material, the clay will sink. The material is no longer buoyant.

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COMPRESSION:

MATERIALS: 1 Balloon and a pair of hands.

PROCEDURE: First, fill the balloon with air. While holding the nozzle shut with one hand, use your other hand to gently squeeze the balloon. Notice the effect on the balloon. The shape of the balloon is altered as it is squeezed. (THE FORCE ACTING ON THE AIR INSIDE THE BALLOON IS COMPRESSION.) Inside the balloon the air is exposed to the elastic force of the balloon's material. Outside the balloon the air is exposed to normal atmospheric compression. By putting the air into the balloon you are creating a new atmosphere with a greater force of compression.

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TENSION:

MATERIALS: 1 strong nylon rope approximately 20-25 feet in length.

PROCEDURE: Gather together several of your friends and divide them into teams of three or four. Organize tug-of-war matches between the teams. Observe what happens to the rope as it is stretched apart from both ends. The rope becomes stiff and straight. (THE FORCE ACTING ON THE ROPE IS TENSION.)

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FRICTION:

MATERIALS: 1 regular sized brick (not a foundation brick, unless you are Hercules), 4 full-size pencils and a flat board.

PROCEDURE: Try to slide the brick across the board using both of your hands. Notice the amount of force you must use to move the brick along. Place the 4 pencils under the brick to act as rollers. Now try to slide the brick again. Observe any difference in the amount of force you must use. (THE FORCE YOU ARE WORKING AGAINST IN THESE EXAMPLES IS CALLED FRICTION.)

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MAGNETIC FORCE:

MATERIALS: 2 magnets.

PROCEDURE: Bring the two magnets close to each other in various ways...ie; sideways, flat, end to end, and observe what happens. When the magnets are brought together at opposite poles they attract eachother. When the magnets are brought together at identical poles they repel from eachother. (THE FORCE ACTING ON THE MAGNETS IS CALLED MAGNETIC FORCE.)

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ELECTRIC FORCE:

MATERIALS: 2 Balloons and some plastic wrap or a sweater.

PROCEDURE: Charge the two balloons by rubbing them with the plastic wrap or against a sweater. Now place one balloon on a level surface and bring the other one close to it. Observe what happens. By charging the two balloons you create a static field and when they are close together they follow one another. (THE FORCE ACTING ON THE BALLOONS IS CALLED ELECTRIC FORCE.)

Here is another experiment using electric force...

MATERIALS: 1 sheet of paper and 1 regular sized comb.

PROCEDURE: Tear the sheet of paper into pieces about the size of a dime. Place the tiny bits of paper onto a flat surface. Brush the comb through your hair several times. Now try and pick up the bits of paper with the comb. Observe what happens. The tiny bits of paper cling to the comb. (THE FORCE ACTING ON THE TINY BITS OF PAPER IS ELECTRIC FORCE....SPECIFICALLY, STATIC ELECTRICITY.)

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ELASTIC FORCE:

MATERIALS: 1 elastic band and 1 pair of hands.

PROCEDURE: Place one end of the elastic band on the index finger of one hand. Do the same for the other end of the band on the other hand. Stretch the band apart until it becomes tense.(At this point the force acting on the band is tension.) Now expand the band by stretching it further. Now hold the band in place. (AT THIS POINT THE FORCE ACTING ON THE BAND IS ELASTIC FORCE.)

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