renewable energy

A waterfall is a place where a river or stream flows over a high, steep cliff or rock. It is a beautiful natural feature often found in mountainous areas where water drops vertically.

Rapids are parts of a river where the water flows very fast over rocks. They look white and bubbly and can be dangerous for boats.

A delta is a low, flat area of land where a river divides into several smaller rivers before flowing into the sea. It is often shaped like a triangle and is formed by sand and soil left by the water.

The regular rise and fall of the level of the ocean caused by the pull of the moon and sun. It happens twice a day and affects how much of the beach is covered by water.

A wave is a raised line of water that moves across the surface of an ocean or lake. It is usually created by the wind and ends by breaking on the shore.

Astronomy is the scientific study of stars, planets, and everything else in space. It is the branch of science that looks at how the universe works outside of Earth's atmosphere.

A constellation is a group of stars that forms a specific pattern in the night sky. People give these patterns names, often based on animals, objects, or mythological characters.

A piece of rock or metal from space that enters Earth's atmosphere and burns brightly. It is often called a shooting star because it looks like a streak of light in the night sky.

A comet is a small object in space made of ice and dust that travels around the sun. When it gets close to the sun, it develops a bright, long tail of gas and dust that can often be seen from Earth.

An asteroid is a large rock that travels through space and orbits the sun. It is much smaller than a planet and is mostly made of rock and metal.