Across
1
Particle of light
3
Substance with pH above 7
5
Chemical element in table salt
8
Icy body with a tail near the sun
11
Reddish electrical conductor
12
Glass that splits light into spectrum
13
Element found in all living things
Down
2
Mass per unit volume
4
Form of thermal energy
6
Substance with pH below 7
7
Path of a planet around the sun
9
Center of an atom or cell
10
Natural satellite of Earth