Summer is almost here. All around Washington, pools will open. Once school gets out, kids will spend hours splashing around in the water, keeping cool, having fun and getting good exercise.

People have been swimming for many, many centuries. In ancient Egypt, royal children swam along the banks of the Nile river. We know this because ancient paintings show them splashing happily in the river. In Greece and Rome, swimming was a favorite activity, too.

Swimming is one of the best kinds of exercise there is. It uses almost all of your muscles, and gives your heart, blood vessels and lungs a good workout. As fun as it is, though, it's important to remember that human bodies don't naturally live in the water. Every time you go swimming, no matter how good you may be at it, you need to review some basic safety rules:

* Use the buddy system. Many camps use this method for kids to stay safe in the water. When you go swimming, pair up with a friend. Your job is to keep an eye on your friend, and your friend's job is to keep an eye on you. Every now and then, someone on shore or at the side of the pool may yell "BUDDY!" Then you and your partner join hands and raise your arms to show that you're both still safe.

* Never push other people into the water.

* Don't swim when you're overheated. If you have just played a fast game of volleyball on the beach and then race into the water to cool off, you may get in trouble. Your overheated muscles may cramp up in the cold water. Rest for a few minutes after your game. Then go for a cooling, relaxing swim.

* Know the conditions of the water you're going to swim in. Find out how cold and how deep the water is before you leap in. Are there rocks on the bottom? Are there any hidden dangers, like sunken logs or weeds in which you might get trapped?

Before you can really enjoy swimming, you need to be pretty good at it. Swimmers are considered beginners until they can easily go 25 yards or more using a basic stroke like the crawl, the backstroke, the breaststroke, or the sidestroke. Until you can do this, you should never go in water that's over your head, even if you have a tube to help you float. Accidents can happen quickly.

Instead of taking chances, why not become a skilled swimmer? It's a lot of fun -- and it's an activity you can do all your life. Maybe you should make learning to be a super swimmer your project for summer. Many organizations -- including the YWCA, the YMCA, Scouts and the Red Cross -- offer swimming programs for young people. You and your parents can find out more from local chapters of these organizations. Tips for Parents -------

The National Safety Council recommends that all parents make sure their children know how to swim. You might also consider teaching your youngster this "drown-proofing" technique called "The Bobbing Jellyfish." Designed by the late Fred R. Lanoue, head swimming coach for Georgia Institute of Technology, it is taught to Marines and Peace Corps volunteers as part of their training. A detailed description of it can be found in the American National Red Cross lifesaving manual.

Here are the essentials of the method. If you are in a situation in which you need to float and conserve energy for a long period of time -- after falling out of a boat, for example -- this technique may allow you to float for several hours without exhaustion: Take a deep breath, and slowly release it as you float face down, with your body in a vertical position. You are essentially hanging in the water. Only the back of the head shows above the water. Let your arms and legs dangle loosely. When you need air, slowly raise your arms, and open your legs. Then thrust your arms downward, and close your legs like a scissors as you raise your head. This will lift the head far enough above the water to take a breath. Then drop back down to the relaxed floating position. Some people may need to scissor-kick occasionally to keep the head close enough to the surface to take the next breath.