Underwater Parachutes

I swim for the swim and dive team. The sport of swimming involves physics in ways I had never previously actively thought about in all my years as a swimmer. There are many forces acting on a swimmer’s body when submerged in water. For one, in order to float, there must be an upward buoyancy force that “lifts” the body through its center of mass. And even though a swimmer is floating, the downward force of weight is still present. When the upward buoyant force on a swimmer equals the weight of the swimmer, equilibrium is reached and he/she will be stationary. Swimming, however, especially in a race, is all about forward propulsion. Thus, in order to move forward through the water, swimmers must apply a thrust force with the palms of the hands and forearms as well as with the legs and feet to gain this propulsion. Whenever an object moves through a fluid, there is always a resistive drag force in the opposite direction. Naturally, drag comes from 1) friction between the water and the swimmer’s skin 2) drag due to surface waves, and 3) drag created by pressure when a swimmer pushes the water away. Resistive forces, though seemingly frustrating to deal with, allow swimmers to move forward through the water.

Building muscle and getting stronger is an important part of swimming, as it is for any other sport. Often times, to help my teammates and I build strength, our coach makes us swim laps with a parachute dragging behind us at practice. The parachute is attached to a long string. At the end of the string there is a waistband that buckles in the front. Below is a picture and link to a video for reference. Water gets caught and builds up in the parachute, increasing the force of drag acting against our bodies’ forward movement. Though the parachutes make us swim slower with them on, the increased resistance ultimately helps us get faster in the long-run because we learn to swim with a stronger pull, a more powerful kick, and a more efficient stroke! Immediately after taking the parachute off, you feel stronger and faster as you glide through the water without the additional resistance. So, don’t forget that resistance can be a good thing! Like anything in life, challenge and discomfort makes us better.

https://www.youtube.com/watch?v=bUK9pfQQHjc

Sources: https://www.real-world-physics-problems.com/physics-of-swimming.html