What Do We Know About Particles?

The quest to understand what matter is made of goes back to the ancient greeks who ted that everything was made of atoms. But in the last 50 years, we know that that isn't the final storya it's like peeling off layers of an onion. By piecing together lots of experimental information, over the past half century, physicists have been able to construct a theory of how these tiny, little objects behave. It's called the standard model of particle physics and it's one of science's most accurate and well tested theories.