Across
1
Second lightest element
4
Form of thermal energy
6
Element found in all living things
7
Biological catalyst
12
Push or pull on an object
13
Ball of burning gas in space
Down
2
Particle of light
3
Natural satellite of Earth
5
Absolute temperature scale unit
8
Blocking of light by a celestial body
9
Smallest unit of an element
10
Naturally occurring inorganic solid
11
Unit of heredity