Geopotential model

Imagine you're standing on a big playground, with a ball in your hand. The ball is like Earth, and the playground is like space. You might notice that as you hold the ball up, it feels heavier than when you hold it close to the ground. That's because the higher up you go on the playground, the farther away you are from the Earth's center, and there's less gravity pulling on you and the ball.

A geopotential model is like a fancy way of talking about how gravity changes over different parts of the Earth. Scientists use math to create a model that predicts how strong gravity will be at different heights above Earth's surface, and at different latitudes (how far north or south you are). This is important because it helps us understand how things like satellites or airplanes will move around in space, and it's also used to help us make really detailed maps of the Earth's surface.

So if we go back to our playground example, a geopotential model would be like a way to predict how heavy the ball would feel at different spots on the playground, without having to actually hold the ball at every single spot. It helps scientists and engineers understand how gravity affects the things we put in space, or how it affects the way we move and measure things on Earth.