Across
1
Form of thermal energy
4
Measure of matter in an object
6
Substance with pH above 7
7
Biological catalyst
10
Blocking of light by a celestial body
11
Solid with repeating atomic pattern
13
Gas essential for breathing
15
Precious yellow metallic element
Down
2
Smallest unit of an element
3
Path of a planet around the sun
5
Unit of heredity
8
Unit of force
9
Mass per unit volume
12
Amplified beam of light
14
Hottest planet in solar system