Task 1: Think about the terms gravity, mass and weight. Write down the meaning of these words.  Now follow this video about the discovery of gravity by Sir Isaac Newton.

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Task 2:  The meaning of gravitational pull is now more clear. Therefore you can give a scientific reason why objects fall to the ground. The size of this force (gravity) is greater with very heavy objects… thus the gravity produced Earth is large and that produced by the Sun is even larger. This is the force that keeps the planets in their orbit.
Do you think that the gravity on the Moon is larger or smaller than that on the Earth?
And, what about the gravity on Jupiter? Is it larger or smaller than that on Earth?

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Task 3: What is the meaning of mass and weight? And what is the relation between weight and gravity?  You must be aware that the words mass and weight are used very often in our language. At times they are not used correctly even in some of your ‘English’ and ‘Mathematics’ text books! So keep this in mind:
– Weight is a force measured in Newtons (N). It is measured by a Newton meter. You can refer to lesson 5.3 Forensic Science investigating an accident, to see how a Newton meter is used.
– Mass is a measure of the quantity of material. It is measured in kilograms (kg) or grams (g) A balance is used to measure mass.
Download pictures 1 and 2 which show the instruments used to measure weight (by a Newton meter) and mass (by a balance).

Follow the lesson found on this link  http://www.schoolsworld.tv/node/304?terms=720

You will now be able to answer the questions shown in task 3.

Be aware that you can convert mass to weight by multiplying by 10.  Therefore a mass of 1 kg weighs 10N.

Similarly you can convert weight to mass by dividing by 10.  Therefore a weight of 100N has a mass of 10kg.