Across
1
Curved glass that refracts light
3
Smallest unit of an element
4
Disturbance that transfers energy
8
Icy body with a tail near the sun
9
Mass per unit volume
10
Molten rock beneath Earth surface
Down
2
Naturally occurring inorganic solid
5
Ball of burning gas in space
6
Biological catalyst
7
Unit of power
11
Blocking of light by a celestial body