Indoor pollution is 10 times more toxic than outdoor pollution.
62
One cubic foot of gold weighs more than 1,200 pounds!
78
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Scientists are learning from the 1700-year-old Lycurgus Cup, which changes colour thanks to nano particles.
0
Because heat expands the metal, the Eiffel Tower always leans away from the sun.
79
A cubic yard of air weighs about 2 pounds at sea level.
31
Iron weighs more after it rusts.
16