What is the Earth made up of?
There are eight planets in our solar system, but the Earth is the only one we know where living things can live. It is our home! Scientists say the Earth has three main spheres, or parts: the hydrosphere, the geosphere and the atmosphere.
The liquid part of the Earth: all the water on and above the surface. Oceans, seas, lakes, rivers… and even clouds!
The solid part of the Earth: all the land on and below the surface. The continents are part of the geosphere.
The gaseous part: a layer of gases that surrounds the planet. It lets living things breathe and protects them.
Do you remember them? The five oceans are the Pacific, the Atlantic, the Indian, the Arctic and the Southern Ocean. The seven continents are Africa, Antarctica, Asia, Europe, North America, South America and Oceania. Oceans belong to the hydrosphere and continents to the geosphere.
You need a small clear bottle, a funnel, water, sand (or gravel) and a little oil. Pour the same amount of each one into the bottle, close it and shake it hard. Then leave it still for about 15 minutes and watch. The sand goes to the bottom, the water stays in the middle and the oil floats on top. Which sphere does each material represent? Which sphere is the most difficult to show in a bottle? (Tip: the air at the top of the bottle is a gas!)
All the living things on Earth (plants, animals, people…) live where the three spheres meet. Some scientists call this the biosphere: the sphere of life.