Transcript You Can Not FORCE Me to Do It!

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
• Magnetism
• Friction
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.
N
S
N
S
Like poles repel (push away) each other.
N
S
S
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.
N
S
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)
Gravity
The 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