Our bodies need protein, and proteins contain nitrogen. The air we breathe has plenty of nitrogen to satisfy our needs. But-that nitrogen is not available to us directly from the air. The only way ...

What makes kitchen plastic wrap cling so maddeningly to itself, and so conveniently to the sides of bowls and plates? Plastic wrap clings for two reasons: it's elastic and it's sticky. That ...

Few minor injuries are as painful as the dreaded paper cut. Just thinking about it probably makes you cringe. However, these cuts are usually small, hardly noticeable, and rarely bleed. So what ...

Fish do drink water, but how they consume it depends on where they live. Water gets into a fish's body through osmosis, the process in which water diffuses from a higher to a lower concentration.

If blood didn't circulate through our bodies, carrying oxygen and nutrients, people wouldn't be able to live. Blood is so important to life that the body constantly makes new blood. There are ...

Picture new parents cooing at their baby on the couch. The baby's quiet and calm, and everyone's at rest. So their heart rates are low, maybe 60 or 70 beats a minute for the adults. What about the ...

Heat is a measure of molecular activity: the faster a thing's molecules move, the more heat that substance contains. And because everything is made of molecules, and molecules are in constant ...

A listener from Ontario, California wrote to A Moment of Science with a question her sons had asked her. The boys wondered why is it that when you get sunburned you often feel chilled. It really ...

You may already know that chocolate can be lethal to your pet, but did you know that onions can be toxic to your cats and dogs too? And I'm not just talking about their breath ...

The thaumatrope was invented by an English physician named J. A. Paris in eighteen-twenty-six. It's credited with being the first cinematographic device and shows us something interesting about ...

Human beings have round pupils; cats have pupils shaped like vertical slits. What's the advantage for cats and people, respectively, in those different pupil shapes? Different pupil shapes seem ...

Let's follow salt into the digestive system and see what happens. In the wall of the small intestine, the salt is absorbed into your bloodstream, making your blood saltier than it was before.