2. What is matter? Matter is anything that takes up space and has mass.
Matter doesn’t have to be visible – air is matter, even though you can’t see it.
Matter is made up of tiny particles (such as a molecule, atom, or electron).
The particles that make up matter are constantly moving (even though you can’t see them!)

3. Three States of Matter
There are 3 states of matter that are common on Earth: solids, liquids and gases.
Solids
Solids are matter that have a fixed shape and volume (amount of space matter takes up).
A solid does not take the shape of the container it’s in.
Examples: Chairs, books, rocks, ice cubes etc.

4. Particles of a Solid
The particles of a solid are packed closely together.
The particles of a solid are constantly moving. They are vibrating in place (even though you can’t see them).
The particles do not have enough energy to move out of their fixed positions.

5. Liquids
A liquid is matter that has a definite volume, but no definite shape.
The particles in a liquid can move more freely than the particles in a solid.
The particles in a liquid have enough energy to move out of their fixed positions, but not enough energy to move far apart.

6. Show What You Know! Which of the following is true about solids?
The particles of a solid are completely still.
The particles of a solid are vibrating in place.
The particles of a solid move freely and do not remain in a fixed position.
Answer: b

7. Why do the particles of a solid remain in their fixed positions?
They remain in fixed positions because they are completely still.
They are unable to move around because there isn’t enough pressure to release them from their positions.
They remain in fixed positions because they don’t have enough energy to move apart from each other.
Answer: c

8. Which of the following illustrations shows the particles of a liquid
Which of the following illustrations shows the particles of a liquid? a) b) c) Answer: c

9. Which of the following is true about liquids?
They have no definite shape, but have a definite volume.
They have a definite shape, but no definite volume.
They have no definite shape and no definite volume.
Answer: a

10. Gases Gas does not have a definite shape or volume.
Particles will spread out as far and evenly as possible. They will completely fill any container or space.
Gas particles move at high speeds in all directions. They have a lot of energy!
Most gases are invisible. But even though you can’t see them, they still are matter!

11. Review Questions: Describe the movement of particles in solids.
2) Describe the movement of particles in liquids.

12. Review Questions:
3) Describe the movement of particles in gases. 4) What do solids and liquids have in common?

13. Review Questions
5) Ms. Alison places 50 ml of a substance into a 75 ml container. The substance quickly fills the entire container. Is it a solid, liquid or gas?