Fun Facts About Blood

Is blood thicker than water? Blood is about twice as thick as water, thanks to all the cells and other bits that float in it.

How long does it take a drop of blood to travel away from the heart and back again? Roughly 20 to 60 seconds.

Why are red blood cells shaped like breath-mint disks with a dent in the middle? The breath-mint design allows cells to twist through capillaries, the tiniest blood vessels. A sphere or cube is less flexible and might get stuck. Also, the dents in the cells add to the surface area, allowing more oxygen and carbon dioxide to pass in and out of the cell.

Why do mosquitos feed on blood? Adult mosquitos actually eat the nectar of flowers. But mosquito babies need protein, not sugar, to grow. So their mothers feed on blood. Bloodsucking mosquito moms find you by sensing your body heat and breath. Then, with their proboscis, they drill a hole through your skin, into a capillary. Their saliva keeps the blood from clotting while they drink.

Is all blood red? No. Crabs have blue blood. Their blood contains copper instead
of iron. Earthworms and leeches have green blood - the green comes from an iron substance called chlorocruorin. Many invertebrates, such as starfish, have clear or yellowish blood.

How much blood is in your body? Blood makes up about 10 percent of your body weight. Weigh yourself and divide your weight by 12 - that answer is about how
many pints of blood your body has - adults usually have roughly 10 to 15 pints. A newborn baby has about one half pint or one cup of blood.