EnhancedResources: added to The Toolkit
Backyard Science title
with
Michelle Moody
The Homeschool Scientist logo

The Science of Summer Sports

close cropped view of a child's hands holding the U.S. flag at an outdoor event
close cropped view of a child's hands holding the U.S. flag at an outdoor event
M

y early morning summer swim practices took place in an unheated pool in the Midwest—where the evening temperatures dipped into the fifties in June. Those practices taught me a lot about the effect of swimming on the human body. For example: Cold water will bring your entire body to full wakefulness at 6:30 a.m.!

For twelve years, swimming was a part of my growing up. As kids, we tested and tried many things. Several die-hard male swimmers on our summer team would shave their heads and legs to reduce drag. We also practiced kicking skills to propel us through the water and kept our hands cupped, assuming these practices would help us get better swim times.

Looking back, we applied a lot of science to our swimming technique. As a veteran homeschool mom, I reflect on those days and can think up several cool science experiments. Of course, I turn everything into a science lesson!

With the 2024 Summer Olympics upon us, it’s an ideal time to turn summer sports activities into science studies. Did you know thirty-two sports are represented in the Summer Olympics?

So let’s dive into some Olympic-sized science!
Swimming
underwater view of a man performing the breaststroke in a pool lane
underwater view of a man performing the breath stroke in a pool lane
O

ne of the scientific “findings” my friends and I often tested was the idea that consuming flavored gelatin in powdered form would enhance energy levels right before a race. The swimmers’ telltale red fingertips identified them as having dipped into the powdered gelatin in hopes of experiencing that burst of energy from the sugar.

I’m not sure there was really any helpful science there! But there is some serious science behind swimming.

When swimmers dive into the water to start a race, their bodies undergo physical changes. First, there is an increase in heart rate. As the swimmers exert themselves, their heart pumps more blood to deliver oxygen and nutrients to the muscles that are working hard to propel them through the water. The increased oxygen and nutrients give muscles the energy they need to keep moving.

Activity #1

Test this with your children by having them take their resting heart rate. Then take their heart rate after swimming across the pool. Also, record their time to cross the pool. What were the differences between the resting and swimming heart rates? What was the effect on the swimming heart rate when they covered the same distance in less time?

Outside forces also affect a swimmer’s performance. For example, drag is a force that resists the motion of an object as that object moves through water or another type of fluid. It plays a crucial role in how swimmers move through the water.

When swimming, people experience two main types of drag. Surface drag is caused by the friction between the swimmer’s body and the water. Form drag is caused by the shape of the swimmer’s body as it moves through the water. Both types of drag slow the swimmer down and require more energy to overcome.

Understanding drag helps swimmers improve their technique and race faster. They reduce it by streamlining their body position—keeping their body long and straight to minimize resistance. Additionally, wearing tight-fitting swimsuits and caps reduce surface drag by smoothing out the swimmer’s body.

Our coaches would look at how we were turning our heads to the side to take a breath when swimming freestyle during practices. Sometimes, the tendency was to lift our heads out of the water instead of a smooth turn of the head to the side. They also looked at our kick form and fingers. Based on their observations they made suggestions that would improve our time. (This is an interesting video on proper techniques for swimming the butterfly stroke.)

Swimmers use techniques such as streamlining their bodies, reducing turbulence, and entering the water at the right angle to minimize drag and move through the water more efficiently.

When watching the swimmers during the upcoming Olympics, check out their form. Do you see the freestyle swimmers lifting their head almost completely out of the water? (You shouldn’t!) Check out their kicking. What do you notice?

Watch some of the instant replays with the underwater cameras. What do you notice about their body, head, leg, arms, and hand placements? How do you think this helps reduce drag?

Activity #2

To understand drag better, you can conduct a simple experiment at home. Fill a bathtub with water and gather objects of different shapes and sizes—such as a toy boat, a ball, and a flat object like a piece of paper. Place each object in the water and observe how they move. Which object experiences the most drag? Why do you think that is?
Activity #3

If you have access to a pool, there is a great, hands-on way to learn about drag. Time your child swimming across the pool in a swimsuit. Then, have them put on a T-shirt and swim the same distance. Ask them: Which took longer? Why do you think the timings were so different? What caused the drag, and how did it affect your timing?

Swimming is not just about getting from one end of the pool to the other—it is a complex interplay of biology, physics, and scientific principles.

For example, temperature regulation is where the body works to maintain a stable internal temperature even when immersed in water that may be cooler than the body. This process involves the exchange of heat between the body and the water, helping to prevent overheating during intense physical activity.

Understanding the concept of buoyancy helps swimmers maintain proper body positioning in the water. Buoyancy is the upward force exerted by water that helps keep objects afloat. By controlling their body position and distribution of mass, swimmers can take advantage of this force to swim more efficiently. Buoyancy plays a crucial role in diving as well.

Diving
I

n the Olympic Games, divers perform gravity-defying twists, somersaults, and spins before slicing through the water with barely a splash.

Diving involves several key physics concepts that influence the diver’s motion and performance in the water. Divers must understand these concepts and how they relate to their bodies to perform flawless dives.

Gravity is a force that pulls all objects toward the center of the Earth. In diving, understanding gravity is critical in how the diver moves through the air and water. Gravity accelerates the diver downward, and divers use this force to generate speed and momentum during their dives. Gravity “pulls” the diver down toward the water.

When an object is placed into water, two forces act upon it—gravity and buoyancy. Gravity pulls the object’s weight to the earth. The buoyancy force pushes the object upward. Archimedes’ principle states that buoyant force on an object in a liquid equals the weight of the liquid displaced by that object. When an object weighs less than the amount of water it displaces, it floats. This ability to float is called buoyancy.

Divers must understand buoyancy to control their position and orientation in the water. They adjust their body position and movements to either float or sink as needed during the dive.

a female diver in mid jump above the dive board in a large indoor pool facility
a female diver in mid jump above the dive board in a large indoor pool facility
Fluid dynamics is the study of how fluids (like air and water) behave when they are in motion. Understanding this helps divers optimize their movements to minimize drag and maximize propulsion. Divers streamline their body position and movements to reduce resistance as they enter the water.

Diving involves various rotational movements, such as flips, twists, and somersaults. These movements require an understanding of rotational motion principles, including angular momentum, torque, and center of mass. Divers use their body position, muscle control, and timing to initiate and control rotations during their dives.

Activity
Try this simple experiment to help your children visualize buoyancy and displacement. You will need two glasses of water, a couple of ice cubes, and a penny.

First, mark the water levels in both glasses. Then, place the ice cubes into one glass of water. Drop the penny into the other glass of water.

What happens?

The ice cubes should float, and the penny should sink. Why?

Did you notice the water level rise in the glass when the ice cubes were added? (The level rose on the glass with the penny, but not enough to notice.)  This is because when an object is placed in water, it pushes some of that water away. This moving away of the water is called displacement.

Fencing
cropped view of two youths in fencing uniforms sitting on a bench, taking a break as their helmets rest on the red carpet ground and their foils lean against the bench
a female diver in mid jump above the dive board in a large indoor pool facility
F

encing is a sport that requires not only physical skill and agility, but also a deep understanding of scientific principles. Let’s explore some of the science behind fencing.

A few definitions to know before we look at physics and fencing:

The strip is the rectangular playing where fencers compete during bouts or matches. It is also called the piste.

In fencing, an attack refers to the offensive action taken by a fencer to try to score a point by hitting the opponent’s valid target area with their blade. The attack is initiated by the fencer who assumes the role of the attacker, known as the “offensive fencer.”

A parry is a defensive action used to deflect or block an opponent’s attacking blade, preventing it from landing a hit or scoring a point. The primary purpose of a parry is to protect oneself from an incoming attack while setting up an opportunity to launch a counterattack.

A riposte in fencing is a defensive counterattack launched by the fencer after successfully parrying the opponent’s blade. The riposte follows a parry, which deflects the opponent’s attack, creating an opening for a swift and decisive response.

Newton’s Second Law of Motion states the greater the mass of an object, the more force it will take to accelerate the object.

Mathematically, this law can be expressed as: [ F = ma ]

Where: ( F ) is the net force acting on the object
( m ) is the mass of the object
( a ) is the acceleration of the object

Newton’s second law can be observed in the movements and actions of fencers on the strip. When a fencer exerts a force on an opponent’s blade during an attack or a parry, the principles of Newton’s second law come into play.

When a fencer initiates a movement to attack, parry, or riposte, they apply a force to accelerate their blade towards their opponent. The acceleration of the blade is directly proportional to the force exerted by the fencer. A stronger force results in a greater acceleration of the blade, increasing the speed and power of the action.

The mass of the blade and the fencer’s arm also play a role in determining the acceleration of the weapon. Since Newton’s Second Law states that a greater mass requires a larger force to achieve the same acceleration, fencers must consider the mass of their weapon and adapt their form to optimize the force they apply.

Reaction time is how fast or slow your body reacts to a stimuli such as the swing of a sword, a starting gun in a race, or something darting in front of you while you are driving. It is a very important concept and a very complex biological process.

Between the time our body detects a stimulus, such as a sword during a fencing match, and the time it reacts with some type of physical response, a lot happens in our bodies.

Let’s use baseball as a different example. When the eye sees a baseball, it sends a message to the visual cortex. The visual cortex then sends a message to the motor cortex to initiate catching the ball or moving out of the way. The motor cortex sends a message to the spinal cord, which then sends a message to the muscles in the arm and hand to move.

In fencing, split-second decisions can make all the difference between winning and losing a point. The scientific principle of reaction time is crucial in fencing, as fencers must quickly assess their opponent’s movements and react accordingly.

Furthermore, decision-making in fencing involves cognitive processes such as anticipation, pattern recognition, and strategic planning.

Tennis
B

esides swimming, I also loved playing tennis. One of my biggest struggles, though, was reaction time. I remember my high school tennis coach getting so frustrated because there seemed to be a disconnect between my perception of where the ball was going and moving my body to that same area. However, one of my strengths was the power behind my forehand and backhand strokes, which are part of tennis’s biomechanics.

Strong arm muscles—including the forearms, shoulders, and triceps—are essential for generating power and speed in shots like the serve, forehand, backhand, and overhead smash. Muscular strength and coordination help tennis players maintain control, accuracy, and consistency in their strokes and movements.

Muscle flexibility is also important to tennis players. Flexibility describes the ability of musculoskeletal joints to move through a normal and full range of motions. When you raise your arms, reaching both hands up and clapping above your head, you take your shoulder through one direction of its range of motion. Try it!

close up of the string bed of a tennis racket
a female diver in mid jump above the dive board in a large indoor pool facility
Why should we care about flexibility? While new research is showing stretching might not prevent delayed-onset muscle soreness (soreness hours or days after exercises) as previously thought, maintaining good flexibility helps reduce the risk of injury, improve posture, increase range of motion, and improve stress management.

One of the most important rules to remember about stretching is to always warm up before stretching. But why?

Our muscles are composed of many small fibers forming bundles, somewhat similar to many strings forming a rope. When we stretch cold muscles, those fibers literally tear, causing soreness and possibly injury. Warm muscles—warmed by increased blood flow and body temperature as you increase movement—stretch much easier and safer just like a warm rubber band stretches farther.

Activity
Grab a rubber band and stretch it between your fingers, noticing its easy elasticity and wide range.

Now lay the rubber band flat on a shelf in the freezer for a few hours (12 to 24 hours is best). Retrieve your now-frozen rubber band and immediately try stretching it. Does it stretch as far? What happens if you stretch it too far now that it’s frozen?

It breaks! This analogy demonstrates why we want to move around some before stretching.

Science plays a vital role in every summer sport, providing athletes with the knowledge and tools to enhance their performance and prevent injuries. Whether it’s understanding the biomechanics of a swimmer’s backstroke, the physics of a diver’s rotation, the forces at play in fencing, or the importance of flexibility in tennis—scientific principles apply to each of the thirty-two sports in the Summer Olympics.

Bonus Activities:

This month’s bonus activity pack for print subscribers includes:

  • Summer games vocabulary activity
  • A working model of a forearm to help understand the biomechanics behind a tennis stroke
  • Charts to record activity findings
  • Reaction time experiment with a set of worksheets
Additional Resources
Enjoy some homeschool science lessons while your family follows the Summer Olympics. “You know you’re a homeschooler when…. You watch diving and discuss rotational motion!”
-Michelle
Michelle Moody headshot
M

ichelle Moody, is a veteran homeschooling mom and owner of Thehomeschoolscientist.com. After earning a masters degree in child development and education, God’s plan took her into a 12 year biotechnology career. She came home to homeschool. Now, she has returned to her first love of helping children explore and discover the world God has gifted us. Besides homeschooling her own children, Michelle has taught in the traditional classroom, in co-ops, and on the mission field in Bangladesh.