Special thanks to Aaron Harmon, Susan Kaliski and Scott Powell of Down Under Surf & SCUBA for their technical assistance with this article.

In 1943, the famed oceanographer Jacques Cousteau, along with Emile Gagnan, invented the aqualung, more commonly referred to as SCUBA (self-contained underwater breathing apparatus). SCUBA made divers more mobile and revolutionized exploration of the oceans. Since then, many advances in SCUBA technology have made the equipment easier to use, safer and more affordable, allowing many people to enjoy this fascinating adventure. The Professional Association of Diving Instructors (PADI) says that each year, almost 1-million people get certified for recreational SCUBA diving. You can undertake weekend outings to explore offshore shipwrecks and coral reefs or go on longer dive vacations to exotic locations, perhaps meeting such creatures as sharks, dolphins and whales.

Photo courtesy NOAA/Dept. of Commerce
A SCUBA diver

In this article, we will look at the underwater world, examine the SCUBA equipment and explore how your body reacts to the underwater environment. You'll also find out what you need to do to take part in this sport.