You Can Not

FORCE Me to Do It!

What Is Force?

It takes a force to move something.

A force is a push or a pull . . .

that causes an object to move, stop, or change direction.

When you push an object, it moves away from you.

PUSH

• A push is a force that causes something to move opposite of the force.

• Examples:–Push a door open–Pushing a swing

When you pull an object, it moves toward or with you.

PULL

• A pull is a force that causes something to move towards the force.

• Examples:–Pull a door open–Pulling a rope–Pulling a wagon

Is this a push or a pull?

Is this a push or a pull?

Is this a push or a pull?

Is this a push or a pull?

Is this a push or a pull?

Is this a push or a pull?

Is this a push or a pull?

Is this a push or a pull?

What is the pulling force called?

Three major types of forces in the world.

• Gravity • Friction

• Magnetism

MAGNETISM

• Magnetism is the force of repelling (pushing) or attraction (pulling) between two poles of a magnet.

Magnets are attracted to only certain types of metals. They are

not attracted to:

• glass

• the metal tin (tin foil)

• the metal nickel

• the metal copper

• plastic

• water

• wood

All magnets have two poles: a north pole and a south pole.

• Opposite poles attract (pull towards) to each other.

Like poles repel (push away) each other.

S S

SSN

N N

N

What force is represented in the above picture?

A. A pushing force

B. A pulling force

C. A magnetic force

D. Both A and C

Each pole of a magnet has its own magnetic field around that pole.

S

N

All items in the magnetic field move towards the magnet if they are made out of the right type of metal, as they are attracted to the magnet.

GRAVITY• Gravity is the force that pulls all objects in

the universe towards each other’s center.

• Earth’s gravity constantly pulls all things on earth towards earth’s center.

– This is why when you drop something, it always falls down and does not float up.

Gravity is everywhere, including in space.

• The earth and moon’s gravity pull on each other and that is why the moon orbits the earth. (balanced forces)

GravityThe mass of an object determines how much gravity that object has. For example:

The moon and Earth are pulling on each other. The Earth is bigger than the moon so its gravitational pull is stronger. That is why the moon orbits the Earth. What would happen if the moon was bigger than the Earth?

Why do the

planets orbit (go around) the sun?

Gravity of planets and the sun keep the planets in order. (balanced forces)

Without gravity, the planets would move out of their orbits and crash into

each other.

The gravity from the moon also causes the tides on earth.

Friction• Friction is a force that is created when

two surfaces rub against each other.

• Rough surfaces produce more friction than smooth ones.

Smooth Rough

Friction . . .a force that acts against something when two

surfaces rub against each other.

Examples of Friction:• A baseball player sliding

into home on the rough dirt surface has a LOT of friction and can stop.

• A sled on a smooth ice

surface will keep sliding and is hard to stop because it has only a little friction.

This is also why roads and tires are not smooth. Yes, roads are flat, but not

smooth.

What causes the leaves to fall to the ground during the autumn season?

A.Magnetism

B.Pushing force

C.Gravity

D.erosion

An object moves because a ____________ has been applied to it.

A.Force

B.Friction

C.Magnetism

D.Gravity

Which of the following is an example of a force that is different from gravity?

A. an apple dropping to the floor

B. a boy slamming a door

C. a leaf falling to the ground

D. water dripping from a faucet

Forces in My Everyday Life!

Pulling Forces Pushing Forces