Gravity and Weight/Newton and Gravity

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

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.

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

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

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

Plenary Questions on P. 116/7