As summer gets closer, the weather gets warmer and everyone itches to get outside. One of my personal favorite things to do on those hot summer days is to go swimming! So many people enjoy it and it is something that they do all the time, but the majority of people don't stop to think about all of the physics that is involved in it. And there is a lot!
First, the most obvious is the difference in gravity. When you are just walking around normally, you stay on the ground. You never begin to float towards the sky because of the force of gravity on earth. The force of gravity is 9.81m/s^2. However, as you may know, when you are in a pool or the ocean it is very hard to stay on the ground because there is nothing pulling you down. But you are still on the earth... so how can that be possible? Although the force of gravity is the same, there is an additional force acting in the water called buoyancy. This means that when an object is put in water, it will displace the amount of water equal to its volume. This is why objects appear to be lighter when they are in water.
There is also a lot of resistance in water. Water is about 1000 times more resistant than air and about 91% of a persons energy is lost through drag. Therefore, when swimming competitively, swimmers need to maximize their streamline. They can do this by wearing swim caps. As you can see, there is a lot of physics in swimming. So next time you jump in the pool, think about all of the physics that is going on! Thanks for reading