Lesson Aims
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To understand the difference between
mass and weight.
To be able to calculate the weight of
known masses.
To a scientist, weight and mass are two very
different things.
Mass = the amount of ‘stuff’ which makes
something up. (measured in g / kg).
Weight = force of gravity pulling down on
you (measured in N).
Complete the worksheet-weight and mass.
We know that gravity pulls us down towards
the centre of the earth.
On Earth, gravity pulls on every 1kg with a
force of 10N, (10N/Kg), so an object with a
mass of 1kg will have a weight of 10N.
Therefore, to calculate weight on Earth, you
simply multiply the mass by 10.
How to calculate weight
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Calculate the weight of Mr Gabb on Earth. His mass is
approximately 85kg (on a good day).
Mass x 10 = weight
85 x 10 = 850N
After Christmas, his mass goes up to about 87kg,
what will his weight be?
Mass x 10 = weight
87 x 10 = 870N
•Jeff’s mass is 300 Kg
•The gravity on Earth is 10 ms-1
•If weight = mass x gravity
•Then Jeff’s weight on Earth =
300 x 10
•On Earth Jeff weighs 3000 N !!
•Jeff’s mass is 300 Kg
•The gravity on the Moon is 1.6 ms-1
•Jeff’s mass is 300 Kg
•The gravity on Mars is 3.7 ms-1
•Jeff’s mass is 300 Kg
•The gravity on Jupiter 23 ms-1
•Jeff’s mass is 300 Kg
•The gravity on Saturn is 9 ms-1