Force

Science
class
online

Lets do the review of our previous lesson.

Melting

Freezing

Frost



Boiling

Evaporation

Drying
clothes

Evaporation



Tearing a
piece of
paper

Irreversible
physical change

Cutting hair is
also irreversible
physical change.

Breaking an
egg is also
irreversible

physical
change.



Cutting the
wood is

irreversible
physical
change.

Peeling is also
irreversible
physical
change.

Mixing all
ingredients
when baking is
also irreversible
chemical

change.



Baking is
irreversible
chemical

change.

Burning is
also

irreversible
Chemical
change.

Rusting is an
irreversible
Chemical change.

For the very good review

Tug of war



pull

push

Force

Sounds
interesting,

isn’t it?

Force is a push or a pull acting
on an object.



Pushing
the cart



Push
down

Push
up

Pull inwards

Push
sidewards



Used to measure
force.



Force is measured in
Newtons(N)

In honor with the Scientist “
Isaac Newton ; who

discovered the “Theory
universal Gravitation”.



Newtons first Law of motion:
“An object is at rest, and stays at rest. And
an object is in motion and stays in motion
with the same speed and direction unless

acted upon by unbalanced force.

At rest
The same position

If the hand is
removed,

magnitude

Which hand is exerting a greater force?

left right

The length of an arrow shows the magnitude of
force acting on an object.

left Right

Pull down

Push up

up
left Right

down

We use an arrow to show direction and
magnitude of force acting on an object.

Explain it again …. It
looks confusing.

Force is a push or a pull
acting on an object.



Pushing
the cart