The Equator

The Equator

What is the equator?

Charles is thrilled to discover that in his country he can have one foot in the northern hemisphere and the other in the southern hemisphere. He is at the Uganda Equator to learn more.

The equator runs through Uganda. It is an imaginary line dividing the world in half. Along this line, a magnetic needle has no dip and stabilizes in a perfectly horizontal position.

Science demonstration

Charles watches a demonstration. In the northern hemisphere, water is shown going down a plug-hole clockwise. In the southern hemisphere, it is shown to go down the drain counter-clockwise.

This is to demonstrate something known as the Coriolis effect, a scientifically-proven effect whereby something in motion veers to the left or right when travelling on a rotating body like the earth. Some high-pressure cyclonic weather systems do this, rotating clockwise in the northern and counter-clockwise in the southern hemisphere.

In reality, this motion would not be seen with a small amount of water – a huge mass of fluid is needed – so the demonstrator is using some showmanship to simulate the effect.

Lighter at the equator

Fact or fiction? Charles discovers you are lighter on the equator line.

Weight is the force of gravity acting on a mass. At the equator, gravity is 0.5% less. This means that any weight is 0.5% less along the equator.

This is because the earth is not a perfect sphere. It is flattened at the poles. So when you stand at the equator, you are a few tens of kilometres further from the centre of the earth, than when standing at the poles. Since gravity falls off with distance, this means gravity is slightly less at the equator – though not quite as much as the 3% stated.

With a smile on his face, Charles receives his certificate from ‘The Equator Magnetic Experience’.