Across
1
Natural satellite of Earth
3
Force that attracts objects together
5
Curved glass that refracts light
6
Substance with pH below 7
8
Push or pull on an object
9
Hottest planet in solar system
10
Positive particle in nucleus
Down
2
Gas form of a liquid
3
Unit of heredity
4
Reddish electrical conductor
7
Center of an atom or cell
11
Unit of force