Brain facts
Looking at how something works.
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An average human brain weighs about 1,300–1,400 g, close to 3 lb, almost a bag of sugar.
It is smaller than an elephant's brain (6,000 g) and larger than a monkey's (95 g). A dog's brain weighs about 72 g, and a cat's about 30 g.
Our skin weighs twice as much as our brain.
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The brain is about 60% white matter and 40% grey matter.
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It can hold more ideas than there are atoms in the known universe.
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Information travels at different speeds in different neurons. Transmission can be as slow as 0.5 metres per second or as fast as 120 metres per second.
At 120 metres per second, that is about 268 miles an hour.
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If we could use the power the brain draws, it would light a 10-watt bulb.
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The brain is about 2% of body weight. It is roughly 140 mm wide, 167 mm long, and 93 mm high.
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In early pregnancy, neurons multiply at about 250,000 a minute.
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The brain has about 100 billion neurons.
That is about 166 times the number of people on the planet. Counting them, one a second, would take about 171 years.
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The brain uses about 20% of the oxygen moving through the body, and about 750 ml of blood passes through it every minute.
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At birth the brain weighs about 350–400 g, and we already have almost all the brain cells we will ever have. It is closer to its adult size than any other organ. It stops growing at about age 18.
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After the blood supply to the brain is lost, unconsciousness follows in 8–10 seconds.
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The number of internal pathways the brain can form has been put this way: a one, followed by a line of zeroes 10.5 million kilometres long, if each zero were a standard typewritten character.
First written in 2010 on virtual eye.