Across
1
Force that attracts objects together
4
Amplified beam of light
6
Compound containing oxygen
7
Biological catalyst
8
Icy body with a tail near the sun
9
Natural satellite of Earth
12
Our home planet
Down
2
Unit of power
3
Absolute temperature scale unit
5
Basic unit of life
6
Gas essential for breathing
10
Chemical element in table salt
11
Positive particle in nucleus
13
Disturbance that transfers energy