Okay kiddo, geothermal systems are like big heaters and air conditioners that use the heat from the earth to make your house warm or cool.
So the earth is really hot inside, and geothermal systems take advantage of that. They have pipes that go deep into the ground and bring up the heat. Then, the heat is used to warm up your house in the winter, or cool it down in the summer.
It's like having a magic indoor temperature switch! The system can even switch between heating and cooling to keep your house at just the right temperature.
Geothermal systems are also good for the environment because they use renewable energy - the heat from the earth won't run out like gas or oil could. Plus, they don't use as much electricity as traditional heaters and air conditioners, which means lower bills for your parents.
That's the basics on geothermal systems, I hope that helped you understand!