2.+Matter

**This topic is about the common phases or states of matter - solids, liquids, and gases.**

Welcome to our new topic. Here we will play with and explore the stuff of the universe! Scientists use the PARTICLE MODEL to help us understand and talk about the phases or states of matter.

There are some definitions we need to know about matter and its states:


 * ALL MATTER takes up SPACE and has MASS.**

The particle model of matter helps us understand the different states of matter.

Solids
Have fixed shape, fixed volume, particles move very little, particles arranged in a tight pattern.

Liquids
Have no fixed shape but a fixed volume, particles move past one another easily but are not in a neat arrangement.

Gases
Have no fixed shape or volume, particles move rapidly and have large spaces between them.

**Some things to try. . .**

Have a look at these animations to see what the particles are doing in solids, liquids and gases.

Now play with this animation showing how the particles move when heated.

Remember that all matter takes up space and has mass. This means each different kind of matter has a different density. Density is the ratio of the mass of an object and the volume it occupies. Density is a useful thing to measure because it can help tell us what kind of matter we are dealing with.
 * Density**

To calculate the density of a substance we have to measure its mass and its volume. The formula we use is Density = Mass divided by volume. That's D=m/v. Here is a density activity for you to see what measurements to make and how to calculate density.