ELI5: Explain Like I'm 5

Eötvös number

Hey kiddo, do you know what gravity is? It's what keeps us on the ground and keeps the planets in their orbits around the sun. But did you know that gravity is a little bit different on different parts of the Earth?

This is where the Eötvös number comes in. The Eötvös number is a measure of how much gravity changes depending on where you are. Specifically, it measures the difference in gravitational pull between two points on the Earth that are a certain distance apart.

Imagine you and your friend both stand on a scale, but your friend is on a hill and you're on flat ground. Your friend's scale will show a slightly lower weight than yours, because they are farther away from the center of the Earth and therefore experiencing slightly less gravity. The Eötvös number can tell us exactly how much difference there is between your weight and your friend's weight.

Scientists use the Eötvös number to study things like the structure of the Earth's crust and the movements of tectonic plates. By measuring the difference in gravitational pull between different parts of the Earth, they can learn more about how the planet is shaped and how it changes over time.