science lesson G 2, 3

1. Changing in motion
1

2. Ch.9 , Lesson 3
Changing in Motion
Objectives:
The students be able to
1-Understand how Forces can
change an object’s motion.
2-Explore how can we control
friction.
3-Identify different types of
Motion.
Vocabulary:
Friction
2

3. Ch.9 , Lesson 3
Changing in Motion
What causes change in
Motion:
• When each person pulls
on a rope, each applies a
force.
• When forces are equal,
or balance there is
no change in motion.
Vocabulary:
Friction
3

4. Ch.9 , Lesson 3
Changing in Motion
If one person pulls
harder on the end of the
rope the forces are
unequal, or unbalanced,
the rope will move to one
side.
Vocabulary:
Friction
4

5. Ch.9 , Lesson 3
Changing in Motion
So, change in object’s motion
comes from all the forces that
are acting on it.
• Unequal forces cause change
in motion.
• Change in motion occurs
when:
 object start moving.
 Moving object speeds up.
 Moving object slows down
 Moving object changes
direction.
 Moving object stops moving
Vocabulary:
Friction
5

6. Ch.9 , Lesson 3
Changing in Motion
Vocabulary:
Friction
6

7. Ch.9 , Lesson 3
Changing in Motion
How can you control Friction?
What happens when you roll a
ball on the floor?
It will start moving quickly
but soon slows down then it
stops.
Vocabulary:
Friction
7

8. Ch.9 , Lesson 3
Changing in Motion - It is the kind of force that
stops or slows things down.
{It prevents us from slipping
or falling down}
- It is caused when two
objects rub together.
Vocabulary:
Friction
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Friction

9. Ch.9 , Lesson 3
Changing in Motion
Examples for friction:
Vocabulary:
Friction
9
1) Friction between the tires
of a car & the road.
2) Friction between the
bottom of your sneakers
& the ground.

10. Ch.9 , Lesson 3
Changing in Motion
Vocabulary:
Friction
10
3) Friction between the
brakes of the bicycle & the
bicycle wheels.
4) Friction between the train
Wheels & rails

11. Ch.9 , Lesson 3
Changing in Motion
Different materials produce
different amounts of friction
Rough materials rub best,
so they produce a lot of
friction.
Smooth materials rub less.
• Rubber are smooth but
produce a lot of friction.
Vocabulary:
Friction
11

12. Ch.9 , Lesson 3
Changing in Motion
Friction slows things down.
You can’t get rid of it, but
you can change the amount of
friction you have.
• People use slippery things
to reduce friction.
Vocabulary:
Friction
12

13. Ch.9 , Lesson 3
Changing in Motion
• Lubricating doors decrease
friction making doors easy to
open & close.
• Lubricating “putting oil” to
bicycles decrease friction &
makes bicycles move faster.
Vocabulary:
Friction
13

14. Ch.9 , Lesson 3
Changing in Motion
• To increase friction, people
use rough or sticky things.
• In-line skates have a
rubber pad that skaters
use it to slow down and
stops.
Vocabulary:
Friction
14

15. Ch.9 , Lesson 3
Changing in Motion
Tires of cars have rough
surfaces to increase the
friction between the road &
the car preventing cars from
slipping on an inclined plane.
Vocabulary:
Friction
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16. Ch.9 , Lesson 3
Changing in Motion
What are different types of
motion?
Forces can cause objects to
move in different ways.Vocabulary:
Friction
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17. Ch.9 , Lesson 3
Changing in Motion
• Objects can move up and
down or back and forth like
a wave.
• Sound and light waves can’t
be seen but all waves have
the same characteristics.
• The highest part of a wave
is called the crest.
• The lowest part is called
the trough.
Vocabulary:
Friction
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18. Ch.9 , Lesson 3
Changing in Motion
• A wave can be described
and measured by its length.
• Is the distance from one
crest to another.
Vocabulary:
Friction
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Wave length

19. Ch.9 , Lesson 3
Changing in Motion
Check for understanding:
1-What can cause change in
motion?
2-What are 5 examples of a
change in motion?
3-What is friction?
4-Would it be easier to roller
skate on a gravel road or a
smooth road ? why?
Vocabulary:
Friction
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