A plastic garden gnome is travelling around the world to help demonstrate how the pull of gravity changes in different locations.

Gravity is the force that attracts a person or an object to the centre of the Earth. It keeps us on the ground, and it also determines how much we weigh.

Gravity may be slightly stronger or weaker depending on where you are, which means things weigh different amounts in different places on Earth.

The difference is so small – 0.5 per cent or less – that most people using ordinary scales wouldn’t even notice it.

For example, if you weigh 40 kilograms, the difference would be no more than 200 grams higher or lower, depending on where you were.

But even such a small difference would matter to scientists who need to be very accurate when measuring amounts of chemicals for an experiment or comparing weights of different objects.