Most dust particles in your house are made from dead skin!
67
A single speck of dust is half way in size between a subatomic particle and the Earth.
15
Stephen Hawking once tried to find potential time travellers by throwing a party and only sending out invitations after the party.
17
A cubic yard of air weighs about 2 pounds at sea level.
31
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
Sound travels fifteen times faster through steel than through air.
134
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
