Key terms from the particle theory of matter.

3. When energy moves from one thing to another because of temperature differences.
7. A mix of two or more kinds of stuff joined together chemically.
9. Squeezing a thing to make it take up less space.
10. A thing that always has the same mix and can't be made simpler by normal ways.
12. Stuff that has weight and takes up space, made of tiny particles, can be solid, liquid, or gas.
14. To get bigger.
17. To spread out from a crowded place to a less crowded one because of tiny particle movements.
19. The main part of a mix that dissolves the other stuff.
20. When a liquid becomes solid because it gets cold.
21. The force that sticks atoms together to make a molecule or a compound.
22. A tiny part of an atom with a negative charge, spinning around the center.
23. When a liquid turns into a gas by getting hot.
25. A mix of different stuff that can be separated easily.
26. Places around an atom's middle where electrons like to hang out.
28. When a gas turns into a liquid because it gets cold.

1. A clear mix where one thing is mixed into another.
2. When a thing becomes different stuff because of a chemical reaction.
4. A type of stuff made up of only one kind of atom.
5. A thing that gets mixed into a liquid to make a mix.
6. The middle of an atom with the protons and neutrons.
8. A tiny part of an atom with no charge found in its center.
10. When a thing changes how it looks or feels without changing what it's made of.
11. When something solid turns straight into a gas without becoming a liquid first.
13. When a gas turns into a solid without becoming a liquid first.
14. The power to do work or make things hot.
15. The tiniest bit of a substance made up of even smaller parts called protons, neutrons, and electrons.
16. To mix something into another thing until they make a clear mix.
18. When something solid turns into liquid because it gets hot.
24. A tiny part of an atom with a positive charge found in its center.
27. About movement or the motion of tiny particles.