Subatomic particle facts for kids

A subatomic particle is a tiny piece of matter, even smaller than an atom. Atoms are the basic building blocks of everything around us, and subatomic particles are what make up those atoms! They are so incredibly small that you can't see them with your eyes, even with a powerful microscope. Scientists study these particles to understand how the universe works at its most basic level. The most well-known subatomic particles are protons, neutrons, and electrons, which are the main parts of an atom. The study of these tiny particles is called particle physics.

These particles are often held together inside an atom by powerful connections called forces. There are four main forces in nature: gravity, the electromagnetic force, the strong force, and the weak force. Outside of an atom, subatomic particles can move incredibly fast, sometimes almost as fast as the speed of light! That's about 300,000 kilometers (186,000 miles) per second.

Types of Subatomic Particles

Subatomic particles are generally put into two big groups: Baryons and Leptons.

Baryons: Particles Made of Quarks

Baryons are a type of subatomic particle made up of even smaller pieces called quarks. Scientists believe quarks are some of the most basic particles. There are six different types of quarks: up, down, strange, charm, top, and bottom.

Protons and neutrons, which are found in the center of an atom, are examples of baryons. Protons are made of two "up" quarks and one "down" quark. Neutrons are made of one "up" quark and two "down" quarks. In particle reactions, the total number of baryons always stays the same.

Leptons: The Smaller, Undivided Particles

Leptons are generally much smaller than baryons. Unlike baryons, leptons are not made of quarks. Scientists think leptons are fundamental particles, meaning they can't be broken down into anything smaller.

Common examples of leptons include electrons, Muons, Taus, and neutrinos. Electrons are very important because they orbit the center of an atom and are responsible for electricity and chemical reactions.

What Are Antiparticles?

For every subatomic particle we know, there's also an "antiparticle" that is like its opposite twin! An antiparticle has the same mass (how much "stuff" it has) as its normal particle partner, but it has the opposite electric charge. For example, the antiparticle of an electron (which has a negative charge) is called a positron (which has a positive charge).

When a particle and its antiparticle meet, they can't exist together. They destroy each other in a burst of pure energy! This process is described by Albert Einstein's famous equation, E=mc². This equation shows that mass can be turned into energy, and energy can be turned into mass.

Scientists often create these collisions in huge machines called particle accelerators. By smashing particles together at very high speeds, they can create new, often very heavy, subatomic particles that only exist for a tiny fraction of a second before they break apart.

How Scientists Find New Particles

Most new subatomic particles are discovered by making other particles crash into each other at incredibly high speeds. When these high-speed collisions happen, they create a "shower" of new subatomic particles. Many of these new particles are very unstable and decay (break down) extremely quickly.

Because these particles move so close to the speed of light, the rules of special relativity become important. One interesting effect of special relativity is called time dilation. This means that for a particle moving very fast, time actually slows down for it compared to us. This allows scientists to observe and measure these super-fast, short-lived particles over a longer distance than they would expect if time didn't slow down for them.