A lead pencil has no lead, but graphite.

Popcorn pops because the kernels contain minute particles of water, although appearing dry, that explode when the kernels are heated and the water converts to steam. If popcorn kernels are kept in freezer, more of the kernels pop the longer the stay.

Yellowstone National Park was the first national park in the world.

The birth date of Christ is unknown but the Bible implies it was in the springtime. In 320 A.D., Pope Julius I arbitrarily set December 25 and Emperor Constantine, a recent convert, soon made the feast permanent.

When a jet breaks the sound barrier, listeners hear a sound like thunder. But the pilot does not hear this sound.

All the great apes(in captivity) —which include chimpanzees, bonobos(pygmy chimpanzees), gorillas and orangutans—have learned American Sign Language and each has taught ASL to others of its own kind and they can use computers.

Looking for a wall stud? Try an electric razor. Run it lightly along the wall. The sound it makes will change as soon as you hit a stud. (Tone of vibration)

Did you know you are one-quarter inch taller in the morning than you are later in the day? During the day, as you walk around, the cartilage between your vertebrae becomes mashed. At night, when your body relaxes, the vertebrae put less pressure on the cartilage, which allows it to expand.