Rizzler

8.2 Force

Recall your Do and Discover activity. The crumpled paper, pencil, paper clip, and inflated balloon moved because you applied force to them.

Wind Moves Objects

Wind exerts force. It can cause an object to move. It can blow leaves, twigs, sands, and even stones from one place to another.

How do you think windmills and pinwheels move? The force of the wind makes the mills move. They follow the direction of the wind. This is also the same in pinwheels.

Try this activity. Get three small pieces of paper. Place them on a table. Take a deep breath and blow on the pieces of paper. What happened to the pieces of paper? Were you able to move them? After the activity, pick up the pieces of paper.

How do you know if force is acting on an object?

8.2 Force

Recall your Do and Discover activity. The crumpled paper, pencil, paper clip, and inflated balloon moved because you applied force to them.

Wind Moves Objects

Wind exerts force. It can cause an object to move. It can blow leaves, twigs, sands, and even stones from one place to another.

How do you think windmills and pinwheels move? The force of the wind makes the mills move. They follow the direction of the wind. This is also the same in pinwheels.

Try this activity. Get three small pieces of paper. Place them on a table. Take a deep breath and blow on the pieces of paper. What happened to the pieces of paper? Were you able to move them? After the activity, pick up the pieces of paper.

How do you know if force is acting on an object?

Big Idea

Force causes objects to move.

Learning Competencies

identify things that can make objects move such as people, wind, water, and magnets

describe effects of

Magnets Move Some Objects

You may have seen and used refrigerator stickers. Have you ever wondered why they easily get stuck onto a refrigerator? These stickers contain magnets.

A magnet pulls metallic objects such as iron nails, paper clips, pins, and other metals. These metallic objects are called magnetic. Objects that are not affected by the pull of magnets are called nonmagnetic.

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To learn more about magnetic and nonmagnetic objects, tap this icon for the activity.

A magnet has two ends called poles. One pole is called the north pole and the other pole, the south pole. Magnetic field is the invisible force around a magnet.

magnetic field

The north pole of one magnet attracts the south pole of another magnet. To attract means to pull an object towards you. The north pole of one magnet repels the north pole of another magnet. To repel means to push an object away from you.

If a magnet is cut into halves, you get two smaller magnets, each with its own north and south poles.

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Magnets are used in a lot of objects. Around the house, you will find magnets in:

doorbell

electric fan

headphones

refrigerator

television

telephone

Can you name other objects that have magnets?

Gravity Moves Objects

A force pulls objects toward Earth. This force is called gravitational force or gravity. If you throw any object upward, it will go down.

You cannot see gravity. You can only see its effects. It pulls all objects towards the ground.

Water flows from a faucet because it is pulled down by gravity.

Fruits from a tree fall to the ground. All of these happen because of gravity.

Static Electricity Moves Object

Get a plastic comb. Rub it on your hair several times, then place it near small pieces of paper. What happened?

When you rub a plastic comb on your hair, it becomes charged and attracts the bits of paper. This is an example of static electricity. Static electricity pulls the bits of paper.

Static electricity is an electric charge between objects that are rubbed. Try rubbing a balloon with a piece of cloth. Place it near small pieces of paper. What did you observe?

This time, rub the inflated balloon with a piece of cloth. Place them near each other. What happened?

Do you know that magnet, gravity, and static electricity are forces that act at a distance? These forces are able to move objects without direct contact.

Force Has Effects

Some forces cause objects to change in length and shape.

Stretching an object makes it longer. Try pulling a rubber band. What happened?

Compressing can make an object shorter. Squeeze a water bottle. What happened?