Subatomic particle

Everything is made of tiny bits.

Some bits are made of even smaller parts. We call these composite particles. A proton is one of these. It is made of tiny quarks.

Other bits are not made of anything else. These are called elementary particles. An electron is an elementary particle.

These bits can act like waves. They can also act like tiny balls. This is a strange way to be!

Scientists study these bits to learn about our world.

Everything in our world is made of atoms. But atoms have even smaller parts inside them. We call these subatomic particles.

Some particles are composite. This means they are made of other parts. A proton is a composite particle. It is made of three quarks. A neutron is also a composite particle. These two stay together in the center of an atom. This center is called the nucleus.

Other particles are elementary. These are not made of anything else. An electron is an elementary particle.

Scientists group these particles in different ways. Some are called fermions. These particles have mass and do not overlap. Others are called bosons. These are force-carrying particles. They help parts of the atom interact. The photon is a boson that carries light.

These tiny bits are also very strange. They have wave-particle duality. This means they act like tiny balls. They also act like waves. You cannot always know where a particle is and where it is going at once. This is called the uncertainty principle.

Everything in our world is made of tiny building blocks called subatomic particles. These particles are smaller than an atom. Scientists study them using particle physics and nuclear physics. There are two main types of these particles. Some are called composite particles. These are made of even smaller parts joined together. Others are called elementary particles. These are the simplest parts and are not made of anything else.

How these particles work depends on what they are made of. A proton is a composite particle made of quarks. It has two up quarks and one down quark inside it. A neutron is also composite and has two down quarks and one up quark. These particles often group together to form a nucleus. Most composite particles are called hadrons. These include baryons, which have an odd number of quarks. They also include mesons, which have an even number of quarks.

Learning about these tiny bits has taken a long time. Many scientists helped us understand them through different discoveries. J.J. Thomson identified the first subatomic particle, the electron, in 1897. Ernest Rutherford discovered the alpha particle in 1899. He also found the proton in 1919 and the neutron in 1920. Later, James Chadwick discovered the neutron in 1932. The top quark was found in 1995. The Higgs boson was discovered much later in 2012.

Scientists use special groups to organize these particles. One group is called fermions. These particles have mass and do not overlap. Quarks and leptons are types of fermions. Another group is called bosons. These are force-carrying particles like photons or gluons. Some bosons have no rest mass, but W and Z bosons are different. They have relatively large rest masses.

Subatomic particles also behave in very strange ways. They have something called wave-particle duality. This means they can act like tiny particles or like waves. This is why some people call them wavicles. There is also the uncertainty principle. This rule says we cannot measure a particle's position and momentum exactly at the same time. These rules help us understand how the smallest parts of our universe act.

Subatomic particles are the tiny building blocks that exist inside atoms. They are much smaller than the atoms themselves. Scientists study these particles using two main fields: particle physics and nuclear physics. Particle physics looks at the smallest parts of the universe. Nuclear physics focuses on how protons and neutrons behave in an atomic nucleus. To understand the universe, we must understand how these particles interact.

According to the Standard Model, particles fall into two main categories. The first category is elementary particles. These are the simplest parts of matter. They are not made of anything else. The second category is composite particles. These are made of multiple elementary particles held together. For example, a proton is a composite particle. It is made of two up quarks and one down quark. A neutron is also composite. It consists of two down quarks and one up quark. These particles often group together to form a nucleus.

We can classify particles by how many quarks they contain. Most composite particles are called hadrons. The word hadron comes from the Greek language. Lev Okun introduced this term in 1962. Hadrons are divided into two groups: baryons and mesons. Baryons contain an odd number of quarks. Most baryons have exactly three quarks. The proton and neutron are the most famous baryons. Mesons contain an even number of quarks. Most mesons consist of one quark and one antiquark. Aside from protons and neutrons, most hadrons are unstable. They decay into other particles in microseconds or less.

Particles are also grouped by a property called spin. This helps scientists understand how they behave in space. Particles are either bosons or fermions. Fermions have an odd half-integer spin. In the Standard Model, all elementary fermions have a spin of 1/2. This group includes quarks and leptons. Bosons have an integer spin. Many bosons are force-carrying particles. For example, photons carry electromagnetism. Gluons carry the strong force. The Higgs boson is the only elementary particle with a spin of zero.

History shows how our understanding of these particles has grown. J.J. Thomson identified the electron in 1897. This was the first subatomic particle ever identified. Ernest Rutherford discovered the alpha particle in 1899. He also found the proton in 1919. James Chadwick discovered the neutron in 1932. Many more discoveries followed over the decades. The top quark was discovered in 1995. The tau neutrino was found in 2000. Finally, the Higgs boson was discovered in 2012. Each discovery changed how we see the world.

Subatomic particles follow very strange rules called quantum mechanics. One important idea is wave-particle duality. This means particles can act like solid objects or like waves. Some scientists even call them "wavicles" because of this. Another rule is the uncertainty principle. This principle states that we cannot measure certain properties at once. For example, we cannot know a particle's exact position and momentum at the same time. These rules are very different from the physics we see in everyday life.

Understanding these particles is vital for many sciences. Chemistry relies on the behavior of electrons, protons, and neutrons. These particles allow atoms to bond into molecules and crystals. Physics uses particle interactions to understand the entire universe. Even the laws of conservation of energy and momentum apply here. These laws help scientists calculate what happens in massive stars and tiny quarks alike. By studying the smallest things, we learn about the largest systems in existence.