Everything around us has to be made from something. The different types of stuff that make up the world around us are called "materials".(In science materials doesn't just mean types of cloth!) Materials come in three main forms- Gases, Solids and Liquids.
 
 
 

Solids.Solids are what we normally think of when we talk about materials. The important thing about solids is that they have a definite shape and they will keep that shape unless we cut, bend or squash the material. In a solid the tiny atoms or molecules that make up the material are tightly packed together and hold each other in place.

 
 

Liquids.The most common example of a liquid is water, but there are plenty of other liquids around: oil,petrol,mercury,etc The molecules in a liquid are also tightly packed together but in a liquid they are not holding each other in place, they can move around each other. This means that liquids flow. They can be poured from one container to another. It also means that you cant carve a shape out of a liquid. The molecules that make up the liquid just slip and slide past each other until your shape becomes a puddle! If you want to carry a liquid around you will need to put it into a container.

 
 
 
 

Gases.People often forget about gases altogether, that's because most gases can't be seen and most of the time you can't even feel them. But gases do exist. Air is a mixture of the most common gases, and air certainly exists or we would all stop breathing! You can soon show that the space around you is full of air, get a large sheet of cardboard and hold it with a friend. Now try to run across the playground. If you hold the card upright the air gets in the way and it is difficult to run -you have to push the air out of the way. If you hold the card flat then it cuts through the air. There are lots of other simple experiments that show that gases really exist. Blowing bubbles in water, trying to squash air in a blocked syringe or jumping out of an aeroplane with (or without) a parachute.  The molecules in a gas are well spread out, they do not hold onto each other at all and will shoot off in all directions. If you want to carry a gas around you will need to make sure your container has a good lid.

 

Gases, Solids and Liquids are sometimes known as the different states of matter. This is because many materials can change from being a gas to a liquid or a solid. Water is a good example, it can come as liquid  water in a glass or as a solid ice cube or as a steaming gas.
 
 
 

Why not try the Changing state quiz?

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