Forces are pushes or pulls.
Did you know that Forces:
- Can change the shape
or size of an object.
- Can change the direction
of a moving object.
- Can change the speed
of moving things moving (can
make things move faster or
- Therefore forces can
change the shape, speed or direction
Forces are measured in Newtons
(N). We measure forces using
a force meter (also known as a
Newton meter). A Force
meter is a piece of equipment
containing a spring, used to measure
forces. Newton meters
have a spring on the inside which
is stretched. The amount
of the stretch in the spring depends
on the size of the force. The units
for measuring forces are Newtons
(N) the unit of force.
Newton meter – another
name for a force meter
Types of Forces:
that a Force is a
push or a pull.
resistance – is
a force that tries to slow
things down that are moving
through air. It is a type
of friction and sometimes
force – is a
force that needs to touch an object
before it can affect it (e.g. friction).
Contact forces need to touch
the thing that they are affecting.
Examples of contact forces
are: Friction, Air
resistance and Upthrust. Many
forces need to touch an object before
they can affect it. These forces
are called contact forces. When
you throw a ball, you have
to touch the ball to put a force
on it. When you go down
hill on a bicycle, the brakes need
to touch the wheel to produce the
force called friction so that you
can slow down.
Drag – air
resistance and water resistance
are both sometimes called drag
Friction – is a force that tries to slow objects
down when two objects rub against each other. Friction is a force that happens when
two things rubbing together.
Oil and grease can help reduce friction. By adding
grease or oil to something it is called lubrication.
Two objects touching have the force of friction
Heat and noise are produced
Air resistance and water
resistance are both types of friction.
Skiers use a special wax to make the
bottom of their skis very smooth.
Rock climbing shoes are made from
a special rubber which helps to increase friction and give
a good grip.
Gravity – is
the force of attraction between any two objects. Our Earth
is very big and therefore has strong gravity that pulls everything
downwards towards the center of
Gravity is any two objects
that have a force of attraction
The weight of something is the
amount of force in which gravity is pulling it down.
Magnetism – is
a force that attracts objects
made of iron - magnets have
force – is
a force that affects something
from a distance like gravity. Some
forces do not need to touch the
things that they are affecting.
Some forces can affect
an object from a distance.
This force is called non-contact
forces. There are three non-contact
forces - Magnetism, Gravity
and Static Electricity.
Speed – is how fast
something is moving. Speed is a way of saying how far
you travel in a certain time. Often measured in metres per second (m/s).
electricity – is
a force which attracts things with
extra electrical charges on them. Static
electricity can attract charged
Upthrust – is
a force that pushes things up.
Solid things, like your chair,
give you upthrust. Things float
in water because of upthrust. When
you are standing on the ground,
gravity is pulling you down. The
upwards force from the ground
stops you from sinking into the
Earth - this upwards force is
resistance – is
a force that tries to slow things
down that are moving through water.
It is a type of friction and sometimes
When you float in water, you feel
so much lighter in weight.
The reason is because the
upthrust from the water is pushing
up against your body weight. You
still have weight, but you do not
feel it. An object will float when
the upthrust cancels out its weight.
Forces can be large or
Forces can work
together or they can work against
Two forces work aginst
each other if they are in opposite
directions. If one of the forces
is stronger than the other, the
forces are unbalances and something
will start to move.
If two forces are the
same in size, the forces are balanced
and nothing will happen.
All objects that are still
or stationary items have
balanced forces on them.
* * * * *
Challenge yourself on
the Force Quiz page to see
what you know about forces!