Across
1
Blocking of light by a celestial body
4
Element found in all living things
6
Unit of electric potential
7
Measure of matter in an object
10
Second lightest element
11
Unit of energy
12
Curved glass that refracts light
Down
2
Path of a planet around the sun
3
Mass per unit volume
5
Basic unit of life
8
Fourth state of matter
9
Magnetic metallic element