Metalwork - Materials - States of Matter

Matter surrounds you in three basic states. These three states are either Solid, Liquid or Gas. Matter is defined as anything that takes up space and has mass. So you already know what Matter is, you just call it by different names, such as glass, plastic, gold, or air. The state the Matter is in makes a difference as to how we use it and sometimes as to how we name it. We all know what water is, so we'll take it as our example of Matter in different states. We usually see water in its Liquid state, and as such it is good for drinking, swimming in and squirting at other people. When water is in its Solid state we call it by other names such as, ice, snow, or frost, depending on its appearance. Finally there is water as a gas which we call steam. The state that Matter is in depends firstly on its temperature and secondly on its Chemical Bonding. The State of Matter is classified by the state it is in at room temperature. If you would like to know the states of the Elements at room temperature look up the Periodic Table of the Elements. You can change Matter from one State to another by warming up the Matter or by cooling it down. Heat is a form of energy and when applied to Matter it affects the bonding of the Molecules, and this determines the State of the Matter. Below we will look as this in more detail.


When Matter is Solid it has a definite shape and a definite Volume. It cannot be compressed and it does not flow. The Molecules in a Solid are tightly packed, because they are low in energy, which stops them from moving around themselves or being forced to move around.

Piece of Wood
Structure of a Solid
Above you can see a block of wood. You know yourself that if you leave the block on a desk it will not flow away... if it did houses would not be fun to live in! Do you think you could compress it or change its volumn ? The answer is no. The diagram above shows the basic structure of a Solid. As you can see the Molecules are tightly packed together and so they have no freedom to move around. This Molecular structure does not allow Solids to flow or change volumn.


When Matter is in a Liquid State it can flow, it has a definite volumn, and it takes the shape of the container in which it is in. The Molecules in a Liquid are not as tightly packed, (because they have slightly more heat energy,) as in a Solid and so they can move around quite a bit allowing the Liquid to flow.

Liquid in a jar
Structure of a Liquid
As you notice when you having a drink and you trip Liquids can flow. They also take up the shape of their container. In a the jar above the red Liquid has the same shape as the jar. If you were to pour the bottle onto the floor then the Liquid would spread out causing a right mess. The Molecules in a Liquid are not as tightly packed as in a solid. There are small spaces between the Molecules which allow them to move in different directions. In a Liquid these Molecules are in a constant state of motion. For all intents and purposes Liquids are not compressible, however because of the small spaces between the Molecules Liquids can be compressed but only very slightly, and so it is not worth considering. As a result Liquids are said to be of a definite volumn.


As a Gas, Matter will totally occupy the container it is contained in. There is no bonding between the Molecules as they are moving too fast. The reason for this is that enough heat has been applied so that the bonds between the Molecules have been broken, and because of the speed at which they are moving the bonds get no chance to reattach themselves. A Gas does not have a definite volumn and can be compressed. Ask an older person to show you a see-through Gas lighter. Inside you will be able to see a liquid but when you press on the button Gas comes out. The Gas inside the lighter is a Liquid because it is compressed, but when you press the button the compression is lost and so you get Gas.

Gas in a bottle
Structure of a Gas
A Gas will occupy all of the container as the Molecules are free to fly around in any direction they choose. If the lid was removed from the bottle asbove the Gas would float out of the botle and mix up with the rest of the air in the room. In a close up view of the Molecules in a Gas you can see that there is a lot of space between the Molecules. There is also no bonding between the Molecules and so they can move around as they wish. If you compress a Gas you change its volumn by reducing the space between the Molecules.