Across
1
Substance with pH below 7
4
Positive particle in nucleus
6
Form of thermal energy
7
Hottest planet in solar system
9
Molten rock beneath Earth surface
Down
2
Tectonic landmass section
3
Force that attracts objects together
5
Gas essential for breathing
8
Tissue that contracts for movement
10
Ball of burning gas in space
11
Glass that splits light into spectrum