Discovery Understanding

Bacteria are truly on the rampage again. They've become immune to the best of our antibiotics, rendering once-treatable infections deadly. However, bacteria do more than make us cringe: Learn how they can be helpful, aiding in meal digestion, air and water pollution control, and even in the treatment of muscle disorders

Over the past century electricity has dramatically changed human lifestyles in much of the world — but how does it work? Segments cover television technology, controlling electricity for different applications, and electromagnetic power.

Without magnetism, we would not have music as we know and experience it today; we would not have computers, motor vehicles, compasses, or MRI scans. Magnetism literally shapes our modern-day world. Learn how magnetic forces were first discovered and how magnetism affects both humans and other animals. Explore the role of magnetism in computers, audio recording, medicine, travel and its importance in your daily life.

What we are, in large part, depends on our genes. It is the hand we are dealt when we are born, and the cards we play our entire lives. You can study as hard you can, but some people will be smarter. The hand you get depends upon the luck of the draw. Which genes you get from your mother, which you get from your father, and how they combine to make you a unique individual, is largely a matter of chance. In the game of life, the shuffling of genes to create a new individual is called sex.

Gazing up at the night sky, you may wonder about the stars twinkling above you: How far away are these tiny glimmers of light? What lies beyond the stars? Where does our tiny planet fit in?

Time - what is it? St. Augustine wrote, "What, then, is time? If no one asks me, I know. But if I want to explain it to someone, I do not know." Perhaps we should ask: Did time have a beginning? A very old question, indeed. But how can we imagine a world before time began? If we count backwards beyond the clock, beyond the calendar, three and a half billion years, we arrive at our own beginning.

Viruses are pure purpose, things on the very edge of life. We can't taste them, smell them or see them, but they're there: in the air, in the water, in every living thing on the planet. They're the tiniest, simplest forms of life on earth, yet they know ways to enter our bodies, kidnap our cells and outwit our immune defenses. Viruses range from the common cold to HIV to H1N1 and have caused epidemics more decimating than wars. Viruses are old. Some believe they're older than all other forms of life. And they are patient. Without a living cell to invade, they wait in a crystalline form, somewhere between life and death. Some can wait for centuries. Their only goal is to reproduce.

A journey into the darkness and finding out how caves were formed. Learn how they are full of life that is so different from a sunlit world above.