Across
1
Curved glass that refracts light
4
Second lightest element
5
Measure of matter in an object
6
Naturally occurring inorganic solid
7
Blocking of light by a celestial body
10
Ball of burning gas in space
Down
2
Natural satellite of Earth
3
Our home planet
5
Tissue that contracts for movement
8
Force that attracts objects together
9
Unit of heredity