1. Resistance, magnetism, upthrust
Can you write the following words five times in the back of your books.
Resistance, magnetism, upthrust
Do now!
He’s going
to blow!
Be careful
Good
Neutral
Excellent
MOODOMETER

2. Today’s lesson What is a force? Contact and non-contact forces
Units of force
Measuring forces

3. What is a force?
A force is a push (or a pull)

4. What is a force?
A force can change the shape of an object

5. What is a force?
A force may also change the speed and direction of an object

6. Contact forces
Many forces need contact to affect an object

7. Non-contact forces
Some forces can affect an object from a distance

8. Forces are measured in units called NEWTONS.
Measuring force
We can measure a force with a forcemeter
Forces are measured in units called NEWTONS.

9. The force of gravity pulling on an apple is about 1 N
Measuring forces
The force of gravity pulling on an apple is about 1 N
1 N

10. The force needed to pull a truck is about 3000 N
Measuring forces
The force needed to pull a truck is about 3000 N
3000 N

11. Let’s measure some forces!
Can you stick the sheet in?

12. Today’s lesson
Upthrust
Measuring upthrust
Floating and sinking

13. Upthrust
Gently lower a mass on a Newton meter into a beaker of water. Sketch a diagram in your book and write a sentence describing what happens.

14. What happens if the upthrust is equal to the force of gravity?

15. What happens if the upthrust is equal to the force of gravity?

16. Which is heavier?
5 kg
5 kg

17. Density
5 kg
5 kg

18. Density Density is the mass of one cubic centimetre of a substance.
So for example, gold has a density of 19.3 g/cm3. This means one cubic centimetre (cm3) of gold has a mass of 19.3 grams.

19. The formula! Density = mass volume Or using the formula triangle; m
g/cm3 g
Density = mass
volume
Or using the formula triangle; m
D x V
cm3

20. Density of regular shapes
volume = length x width x height
density = mass/volume
mass using a scale
height
width
length

21. Now let’s measure some densities.