|MadSci Network: Physics|
Dear Brandon, This is a great question! As I'm sure your teacher has told you, there are four states of matter-- solid, liquid, gas, and plasma. Each state has different properties: solids retain their shapes, liquids seek out the same level in their containers, and gases and plasmas fill their containers (plasmas are essentially completely ionized gases). What determines the state of a given chunk of matter? The energy of the system. As you know, as you raise the temperature of a block of ice (solid water), it will melt to make liquid water, and then evaporate or boil to make steam or gaseous water. By raising the temperature, you have added energy to the system. Neat fact: you have a plasma inside a neon lamp, as that's an ionized gas. Scientists also use the equations to describe the behaviour of plasmas to model interstellar space! So that's how things change state. But what about your question? What about subatomic particles? As your teacher may have told you, atoms are made of protons, neutrons, and electrons. Protons and neutrons, made of quarks, make up the nucleus of the atom. Electrons orbit the nucleus. Electrons and quarks are what we call fundamental particles-- that means that, as far as we know, they are not composite, or there is nothing smaller than them. What happens if we take an atom and add energy to it? The first thing that happens is the electrons will jump to higher and higher orbits (we're getting into quantum mechanics, which is a topic for another day) and will eventually escape the atom, leaving behind an ion. Add enough energy, and all the electrons will be removed. What happens if we add energy to an ion? Well, just like with the atom having an electron (or more) orbiting the nucleus, the protons and neutrons in the nucleus orbit around each other. Adding energy to them put them in different quantum states (again, another question!) which orbit differently. Add enough energy, and you begin to split the nucleus. Add enough, and you can split the protons and neutrons into quarks! That's all you can do to it-- you can put the nucleus in different quantum energy states, or you can break it apart. The latter is what's done at places like Fermilab, CERN, KEK, Brookhaven, and other labs around the world where scientists study nuclear and particle physics. So what's the answer to your question? Unfortunately, it's really that the notions of "state" only have meaning for what's called bulk matter, or macroscopic objects. Our ideas of state break down completely in the quantum world that atoms, protons, neutrons and all the rest inhabit. I hope this helps!
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