The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
Oxygen, carbon, hydrogen and nitrogen make up 90% of the human body.
118
Out of all the senses, smell is most closely linked to memory.
146
Scientists have revived a flowering plant from a fruit stored away in permafrost by Arctic ground squirrel 32,000 years ago.
16
Pure water (H2O) does not conduct electricity on its own.
46
When you walk down a steep hill, the pressure on your knees is equal to three times your body weight.
199
One third of the electricity produced on earth is used to power electric light bulbs!
75