If a person with a mass of 55kgs was to travel to Jupiter or Pluto, the effects of gravity would be very different from those on Earth. Gravity is the pull that a planet exerts towards its centre. Gravity depends on mass. Jupiter has more mass than Earth so its gravity is two and a half times greater. Pluto is much smaller than Earth and so the force of gravity on Pluto is weaker than it is on Earth.

This clip is from:
Science Clips, Forces in Action
First broadcast:
12 October 2007

This clip could be used when learning about the constant force of gravity and how it differs from one planet to another. It could lead to some investigations into calculations of what objects would weigh on other planets. In more advanced sessions it could be used to illustrate the difference between mass and weight. The pupils could be asked to observe how objects stretch elastic bands and springs leading to work measuring mass in newtons. A conversion chart could be provided for the pupils to calculate relative weights on other planets. They could then investigate the effects of different forces on objects by weighing them in air and in water.