Plenty of us have seen these large metal rocks in classical museums or have witnessed a meteor shower, but what exactly are these mysterious space rocks? We often refer to them as 'shooting stars' but this name is a complete misnomer. They are not stars that are falling from the sky, in fact many of the shooting stars that you see are only the size of small specs of dust and more uncommonly can be larger to the size of small cars. Meteorites are the physical space rocks that have landed on the Earth. We can pick them up and study them to gain clues on the early formation of our solar system. And despite what you see in the movies and on television, meteorites are cool when they land not blazing hot and not radioactive in any sense. They are perfectly safe, and there is no reliable historical documentation of anyone ever being killed by a meteorite. There is however a case where an Egyptian meteorite in the early 20th century killed a dog and an incident where a car was bashed in the rear with one, which can occasionally be found on tour.
Now, I mentioned that meteorites are these 'space rocks' that are found on the ground, meteoroids are the same thing but before the enter the Earth's atmosphere, that is they are still in space. These 'space rocks' start off as chunks of rock and metal that start off as small pieces that generally come off of asteroids. They will generally float around in space and occasionally intercept the Earth which can crash land. Meteors are not the large rocks that will cause mass extinctions and will occasionally be just specs of dust.
During the short life that a meteoroid spends while in the atmosphere it is known as a meteor. This is the stage that most people correlate with 'shooting stars' and meteor showers. During the ascent down to Earth, the pieces of dust, rock, and metal heat up (remember that they are moving at very high velocities)