Across
1
Force that attracts objects together
4
Substance with pH above 7
6
Icy body with a tail near the sun
7
Nerve cell in the brain
9
Second lightest element
12
Solid with repeating atomic pattern
13
Infectious microscopic agent
14
Gas form of a liquid
Down
2
Fourth state of matter
3
Biological catalyst
5
Molten rock beneath Earth surface
8
Reddish electrical conductor
10
Positive particle in nucleus
11
Mass per unit volume