Across
1
Biological catalyst
3
Molten rock beneath Earth surface
5
Natural satellite of Earth
6
Form of thermal energy
11
Absolute temperature scale unit
Down
2
Smallest unit of an element
4
Mass per unit volume
5
Measure of matter in an object
7
Compound containing oxygen
8
Particle of light
9
Blocking of light by a celestial body
10
Second lightest element