Optical illusions occur when what the eyes see conflicts with what the brain expects.
75
The force of a suction cup is calculated using F=AP.
15
Iron weighs more after it rusts.
68
The Earth's atmosphere weighs about 5.5 quadrillion tons.
108
0.3% of solar energy from the Sahara is enough to power the whole of Europe.
310
Scientists have developed a microparticle filled with oxygen that can be injected into the blood stream, enabling us to live without breathing.
21
The average temperature at 40,000 feet above sea level is -60 F.
56