What is the difference between a meteor, a meteoroid and a meteorite?
A meteoroid is a small body travelling through space; a meteor is the streak of light it makes when it burns through the atmosphere; and a meteorite is any piece that survives to reach the ground.
These three words describe one object at different stages of its journey, and it helps to follow it from start to finish. Out in space the object is a meteoroid: a natural solid body smaller than an asteroid. The International Astronomical Union describes meteoroids as ranging from roughly 30 micrometres up to about a metre across. Most are tiny, many no bigger than a grain of sand, and they are often debris shed by comets or chipped from asteroids in collisions.
When a meteoroid hits Earth's atmosphere, usually at somewhere between 11 and 72 kilometres per second, it rams into air molecules so violently that the air and the surface of the object glow. That flash of light in the sky is the meteor, which most people call a shooting star. Meteors typically appear around 70 to 120 kilometres above the ground and last only a second or so. A particularly bright one, outshining the planet Venus, is called a fireball, and one that explodes is often called a bolide.
Nearly all meteoroids are completely vaporised. But if a meteoroid is large and strong enough, part of it slows down, stops glowing and falls the rest of the way. Once a fragment lands, it becomes a meteorite. Very small survivors, less than about two millimetres across, are known as micrometeorites.
A simple way to remember it: the meteoroid travels through space, the meteor is the light show, and the meteorite is the solid survivor. So during the Perseid meteor shower you see meteors, but you will not find meteorites from it, because the comet dust that causes it is far too small and fragile to survive.