PUSH
• A push is a force that causes something to move opposite of the force.
• Examples:–Push a door open–Pushing a swing
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
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?
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
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.
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