There may be more to it than not getting enough sleep.
Have you ever been staring into space, or gazing up at a clear, blue sky and suddenly noticed clusters of tiny dots and swirls?
Ever feel sleepy after a big lunch? Find out the science behind taking a siesta!
Chow down salty chips or pretzels, and soon you'll be guzzling your favorite drink. But snacking on sugary foods makes you thirsty, too.
The body must produce the liquid part of blood, called plasma, and the cells that float in it.
Through the early 1600s, physicians believed there were two kinds of blood, one made by the liver and one by the heart...
Although Everest had first been climbed in 1953, this was the first successful ascent to be made without supplemental oxygen.
What keeps penguin's feet from freezing? Penguins' feet don't freeze because of the blood circulating in them.
When fluid blocks the passage of oxygen into the lungs, the resulting suffocation is known as drowning, whether or not the person is submerged in water.