Join Bill as he explores the fascinating, spooky, bizarre world of caves!

Caves come in all different shapes and sizes depending on how they were formed. Spelunkers (people who explore caves) have plenty of descriptive names for caves and the natural rocky features that form within them – soda straws, fried eggs, popcorn and draperies are just a few. Caves can be as simple as one straight passage with a few stalactites overhead, or as complex as a labyrinth, with many stalagmite-carpeted rooms.

Most caves are made by water. Water tastes good if you’re human, but it’s a totally different experience if you’re limestone. Water combines with the carbon dioxide in the soil to make carbonic acid, a substance that eats away at the limestone, dissolving and washing away the rock to make a cave.

There are also caves in rocks other than limestone, like marble, sandstone, basalt and gypsum, and in sea cliffs and volcanoes. There are even caves made of ice.

You never know what kind of living things you’ll run into in a cave. You might happen upon snoozing bats, or weird eyeless fish in an underground lake. Surviving in complete darkness requires an array of natural adaptations. Caves have their own unique forms of life. It’s a whole different world down where the sun doesn’t shine.

The Big Idea

  • A cave is a natural hollow space in the earth.
  • Caves are formed in different ways.
  • Caves have special ecosystems.

Did You Know That?

Most caves have no way in or out? Lechuguilla Cave, in New Mexico, remained hidden until people dug into it.

Caves breathe? Air will rush in or out of the cave, like it’s breathing, in order to maintain equilibrium with the changing air pressure on the surface.

When you’re in a cave, you can wish upon a glowworm? If you’re in Waitomo Caves in New Zealand, hundreds of thousands of glowing insects called Arachnocampa luminosa live on the ceiling and walls of the cave.

Books of Science!

  • “Caves! Underground Worlds”by Jeanne BendickHenry Holt and Company, 1995
  • “One Small Square: Cave”by Donald SilverFreeman Company, 1993.