Across
1
Biological catalyst
2
Positive particle in nucleus
3
Substance with pH below 7
5
Solid with repeating atomic pattern
6
Force that attracts objects together
9
Natural satellite of Earth
10
Our home planet
11
Chemical element in table salt
Down
2
Fourth state of matter
4
Absolute temperature scale unit
7
Icy body with a tail near the sun
8
Form of thermal energy
12
Unit of force