Earth is a giant mass of water and mud revolving around the sun in space. The Earth is the only planet known for life, because it provides food and water and we also have air to breathe on earth. The Earth is spherical and wasn’t always how we know it today.

The Crust is the layer that we walk on. It's very thin and breakable. The crust is about 5-70km deep. It depends whether you are deep under the ocean or high on top of a tall mountain. It is not one continuous surface since it is broken up into enormous pieces that are called tectonic plates.

The Mantle is made of rock but since it's so hot in this part of the earth the rock can act like a liquid and a solid.

The Outer Core is liquid and melted iron because it is very hot by the inner core since it’s the middle of the earth, so obviously it gets hot and melts because of all the layers surrounding it.

The inner core is made of solid and mainly made of rock and iron. It gets very hot from the layers surrounding it so it gets hot and makes some of the other layers melt. The middle layers are hotter and thicker than the top layers because the top layers are more thin and cold. The core is mainly liquid but the top layers are solid.

The Earth is the only planet known for human life. There are four layers representing different things and all of the layers are different.