What are small pieces of space rock and metal called?

Small pieces of space rock and metal are referred to as meteoroids. Meteoroids are defined as solid fragments that travel through space, typically originating from asteroids or comets. They are smaller than asteroids and can vary in size, from tiny grains to larger boulders.

When meteoroids enter the Earth's atmosphere and produce a bright streak of light as they burn up due to friction with the air, they are known as meteors. If they survive this atmospheric entry and land on the Earth's surface, they are then called meteorites. Comets, on the other hand, are icy bodies that, when close to the sun, release gas and dust, forming a glowing coma and a tail.

Therefore, the term meteoroids accurately describes the smaller pieces of space rock and metal before they undergo any transformation upon entering the Earth's atmosphere.