Across
1
Gas essential for breathing
2
Ball of burning gas in space
4
Unit of force
5
Unit of energy
8
Second lightest element
9
Chemical element in table salt
10
The Red Planet
Down
1
Path of a planet around the sun
3
Reddish electrical conductor
6
Glass that splits light into spectrum
7
Biological catalyst
8
Form of thermal energy
11
Center of an atom or cell
12
Measure of matter in an object