Learning to swim well involves mastering a wide range of different skills, but few are more important than learning to trust and understand how you float. Benjamin Franklin actually wrote about learning to trust buoyancy in a letter to a friend, and included this very practical swimming exercise: Stand in chest-deep water and throw an egg several feet towards shore. When it sinks to the bottom, try to pick it up. If you simply bend over, you can’t reach it – natural buoyancy will keep you near the surface.
If you do want to reach the egg, you need to change your body position to overcome buoyancy and propel yourself with arms and legs. At FOSS, we’ve replaced the egg with rings and other pool toys, and our language for teaching the lesson has changed, but Franklin was spot on about the importance of learning to manage buoyancy with body position, and so swimming to the bottom is still one of the most fundamental and earliest skills we teach.
Center of Gravity and Center of Buoyancy
Today, we understand that swimming to the bottom involved finding the right balance between a person’s two centers – the center of buoyancy (the middle of the chest because of the lungs) and the center of gravity (around the hips.) If the center of buoyancy is above the center of gravity, you float up. But if you can get the center of gravity higher, it will help push you down, and position you so arms and legs can push you deeper.
The key lesson is learning how and when to adjust the two centers, and swimming to the bottom is a practical exercise in both going down and up in water. The first lesson is the same as described by Franklin – learning to trust the water to hold you up. We start with submersions, where kids learn that they will bob up when upright. We add in tossing rings from the steps, and kids go through the same process Franklin describes. Our teachers make this a hands-on lesson, often physically positioning the student so their hips are up and lungs down so they can feel how their buoyancy changes.
After learning the feel of the effect of body position, we add in other propulsive skills they have learned in the program – adding pizza arms (arms forward with hands together, forming a closed triangle) to a hips-up posture puts kids in a position to use their hands to propel themselves down, and adding kicks gives them more power and control.
Since this is such an early skill, of course, we aren’t talking about it in terms of physics. But kids grasp the practical implications quickly, and diving for rings is one of the most popular activities we get to do in class, so we actually often use it as a reward – if they do well in other skills, they get to dive for rings. They don’t realize they are learning and practicing one of the most critical safety and swimming skills there is!
Why Managing Buoyancy Matters
First and foremost, understanding buoyancy is a safety skill. It is part of learning to float up, trust the water, and reach safety. Even experienced swimmers can get disoriented (think of ocean swimmers or surfers who get turned by waves) and need to quickly get their bodies in the right position to get back to the surface.
Second, it teaches kids about breath control and how it affects swimming. The instinct is to take a big breath before submerging, but this will increase buoyancy. Swimming to the bottom teaches swimmers to manage how much air they should hold and how it will affect what they are trying to do.
Buoyancy also is key to efficient strokes. Swimming freestyle efficiently requires “swimming downhill,” with hips higher than lungs, to remain flat and streamlined in the water. Otherwise the chest pops up, legs drop, and energy is wasted, tiring a swimmer.
So the next time you are at swim school and you see the kids get excited when the teacher reaches for the rings, know that you are seeing one of the best examples there is of bringing together laughter and learning – and know that the teacher is following in the footsteps of Benjamin Franklin!