Across
1
Molten rock beneath Earth surface
4
Precious yellow metallic element
6
Ball of burning gas in space
7
Solid with repeating atomic pattern
8
Biological catalyst
11
Push or pull on an object
12
Unit of force
Down
2
Our home planet
3
Gas form of a liquid
5
Mass per unit volume
9
Center of an atom or cell
10
Substance with pH below 7
13
Curved glass that refracts light