1. Gravity and Weight/Newton and Gravity

2. Learning Objectives All pupils will know:
An object on Earth has weight because of gravity
That gravity always pulls things towards the centre of the Earth
Use the words gravity, Newton, weight
Most pupils will know:
That gravity is stronger if the objects have more mass
That gravity on Earth is approximately 10N/kg
That Newton worked out how to use ideas about gravity
Why it is important for spacecraft to have as small a mass as possible
Some pupils could know:
That gravity is not the same everywhere on the Earth
How gravity surveys can be used to investigate the structure of the Earth

3. Weight and mass
Your mass is the amount of substance in your body. Your mass is measured in kilograms (kg).
Your weight is a force caused by gravity pulling on your body. The newton (N) is the scientific unit used to measure forces, and so it is also used as the unit for weight.

4. Gravity Object Mass (kg) Weight (N) television 8.0 radio 1.5 chair 50
radio
1.5
chair 50
bag of sugar
1.0
bottle of lemonade 20
Object
Mass (g)
Mass (kg)
Weight (N)
jar of jam
340
0.34
3.4
bag of pasta
500
tin of beans
450
loaf of bread
800
can of lemonade
330

5. 3. Why don’t people in Australia feel like they are upside down?
The person on the top of the Earth is holding out a sports bag

7. Gravity Survey of the Earth
Where are the mountains?
How do we know?
Why could this be useful for us?

8. Plenary
Questions on P. 116/7