Particle Theory and the states of Matter

All Matter is made up of tiny particles This is true for everything in the universe, solids, liquids, gases, and plasmas!

What are particles? Democritus (400 B.C.) philosophised that if you started cutting anything in half, over and over again, eventually you would reach a point where the object would be indivisible. This is what he called the atom.

What are Particles? (cont.) Eventually scientists discovered that atoms were made up of protons, neutrons, and electrons. Scientists now know that protons and neutrons are made up of quarks and that these could be potentially be made up of even smaller strands of energy called strings.

The particles are in constant motion The particles in all matter, are always moving because they all contain energy. This may be obvious in liquids and gases, but even in the most solid of things (like your desk), the particles are in constant motion!

The particles of the same matter are the same For example, all particles of water in the world are made up of two hydrogen atoms, and one oxygen atom!

There is space between the particles. Actually, the space between the particles is larger than the particles themselves. This is even true for solids. They particles need space to move.

There is attraction between like particles Water particles are attracted to other water particles. Nitrogen particles are attracted to other nitrogen particles. Helium particles are attracted to other helium particles. Gold particles are attracted…I think you get the point!

5 Postulates of the particle theory of matter All matter is made up of tiny particles The particles are in constant motion There is space between the particles Particles of the same matter are the same There is attraction between like particles

Solids Solids have a definite shape, because the particles have less energy, which means they move slower, have more attraction and less space between them. The particles vibrate in a lattice like pattern.

liquids Liquids take the shape of the container they are in, because the particles have more energy than solids, which means they move faster, have less attraction and more space between them. The particles move freely around each other.

Gases Gases fill whatever space is available to them, because the particles have even more energy than liquids, which means they move even faster, have nearly no attraction and a lot more space between them. The particles move freely around everywhere.