Across
1
Unit of power
4
Compound containing oxygen
5
Second lightest element
7
Solid with repeating atomic pattern
9
Center of an atom or cell
12
Form of thermal energy
Down
2
Unit of force
3
Mass per unit volume
6
Tissue that contracts for movement
8
Molten rock beneath Earth surface
10
Preserved remains of ancient life
11
Chemical element in table salt
13
Curved glass that refracts light