1. States of Matter 5 States of Matter ?

2. States or Phases There are five main states of matter. Solids, liquids, gases, plasmas, and Bose-Einstein condensates (BEC) are all different states of matter. Each of these states is also known as a phase. Elements and compounds can move from one phase to another when specific physical conditions are present. A "phase" describes a physical state of matter. The key word to notice is physical. Things only move from one phase to another by physical means. If energy is added (like increasing the temperature) or if energy is taken away (like freezing something), you have created a physical change.

3. States or Phases One example is temperature. When the temperature of a system goes up, the matter in the system becomes more excited and active. Scientists say that it moves to a higher energy state. Generally, as the temperature rises, matter moves to a more active state.

4. Solid Solids are usually hard, because their molecules have been packed together. The key is that the solids hold their shape and they don't flow like a liquid. Even when you grind up a solid into a powder, you will see tiny pieces of that solid under a microscope. The atoms inside of a solid are not allowed to move around too much. This is one of the physical characteristics of solids.

5. Liquid Liquids fill up the shape of a container. If you pour some water (H 2 O) in a cup, it will fill up the bottom of the cup first and then fill the rest. The water will also take the shape of the cup. The top part of a liquid will usually have a flat surface. That flat surface is the result of gravity pulling on the molecules. Putting an ice cube (solid) into a cup will leave you with a cube in the middle of the cup because it is a solid. The shape of the solid cube won't change until the ice becomes a liquid. Another trait of a liquid is that it is difficult to compress. When you compress something, you measure out a certain amount of material and force it into a smaller space. Solids are very difficult to compress.

6. Gas There is something called the atmosphere. That's a big layer of gas that surrounds the Earth. Gases are random groups of atoms. In solids, atoms and molecules are compact and close together. Liquids have atoms that are spread out a little more. Gases are really spread out and the atoms and molecules are full of energy. They are bouncing around constantly. Gases can fill a container of any size or shape. It doesn't even matter how big the container is. The molecules still spread out to fill the whole space equally. That is one of their physical characteristics. Think about a balloon. No matter what shape you make the balloon, it will be evenly filled with the gas molecules. The molecules are spread equally throughout the entire balloon. Gases hold huge amounts of energy, and their molecules are spread out as much as possible. With very little pressure, when compared to liquids and solids, those molecules can be compressed.

7. Plasma Plasmas are a lot like gases, but the atoms are different, because they are made up of free electrons and ions of an element such as neon (Ne). You don't find naturally occurring plasmas too often when you walk around. They aren't things that happen regularly on Earth. If you have ever heard of the Northern Lights or ball lightning, you might know that those are types of plasmas. It takes a very special environment to keep plasmas going. Lightning, stars, fluorescent bulbs, neon signs.

8. B.E.C. Bose-Einstein Condensate Kelvin scale If plasmas are super hot and super excited atoms, the atoms in a Bose-Einstein condensate (BEC) are total opposites. They are super unexcited and super cold atoms. A cold ice cube is still a solid. When you get to a temperature near absolute zero, something special happens. Atoms begin to clump. The whole process happens at temperatures within a few billionths of a degree, so you won't see this at home. When the temperature becomes that low, the atomic parts can't move at all. They lose almost all of their energy. Since there is no more energy to transfer (as in solids or liquids), all of the atoms have exactly the same levels, like twins. The result of this clumping is the BEC. The group of rubidium atoms sits in the same place, creating a "super atom." There are no longer thousands of separate atoms. They all take on the same qualities and, for our purposes, become one blob.

9. Density Density is the amount of a substance in a specific area. Water has a greater density than ice, which has a greater density than water vapor. When you decrease the volume of a container (and keep the same amount of matter) you will increase the pressure. If you increase the temperature of a container, you will increase the pressure. The density of a substance is the relationship between the mass of the substance and how much space it takes up (volume). D = m/v

10. Density Generally solids are more dense than liquids because their molecules are closer together. The freezing process compacts the molecules into a smaller space. The solid version of most compounds is more dense than the liquid version. Liquid states are always more dense that the gas state (under normal conditions). There are always exceptions in science. Water (H 2 O) is special on many levels. It has more space between its molecules when it is frozen. There's a whole expanding effect when the molecules organize into a solid state. Water is a special case where the solid is actually less dense than the liquid form. Ice floats at the top of your soda because it is less dense than the surrounding liquid.