How is a crater made?
A big space rock can make a giant hole in the ground. Here is how it happens.
Most space rocks are small and burn up in the air. But once in a very long while, a big one reaches the ground.
A big space rock is going very, very fast when it lands. Much faster than a bullet. When it hits, all that speed turns into a huge burst of energy, like an explosion.
The explosion pushes rock and soil outwards in every direction. It leaves a round bowl in the ground with a raised edge, called a rim. That bowl is a crater.
Craters are nearly always round, even when the rock comes in at a slant. That is because the explosion spreads out evenly.
Meteor Crater in Arizona, in the United States, is a good example. It is more than a kilometre wide. It was made about 50,000 years ago by an iron space rock perhaps 30 to 50 metres across.
On Earth, wind, rain and plants slowly wear craters away. That is why the Moon has far more craters to see than Earth does.
Meteor Crater is about 170 metres deep, about as deep as a 50-storey building is tall.
Ask an adult to help you make craters by dropping marbles into a tray of flour. Follow the crater experiment sheet.