Whoosh!

The air rushes over your face as your swing soars upward. You’re floating for a moment, high in the sky, and then—zoom!—you swing back again.

The thrill of a swing is thanks to some forces of nature called “gravity” and “tension,” along with the inertia (in-ER-shuh) of an object.

Gravity is a force that pulls objects toward the center of the earth. It’s the reason you and your swing seat come back down after you’ve soared upward.

Tension is the force pulling the chain toward the pivot on the top of the swing, which acts opposite to gravity.

Inertia is the tendency (habit) of a mass to keep moving until a force stops it. On the swing, your body is the mass in motion. The force that stops you is friction.

Scientists like Newton, Hubble, and Kepler have studied these forces through the years. But it was God who created these forces during creation week. The Bible says that God keeps the world running with them (Genesis 8:22; Jeremiah 33:25; Hebrews 1:3). And thanks to him, the forces at play help us to play!

Seesawing

Have you ever tried to seesaw (teeter-totter) by yourself? It probably wasn’t any fun. You need a friend to sit on the other side of the plank. When a friend joins in, the forces of nature come to play, too!

To seesaw, you and your friend need balance—also called equilibrium (EE-kwuh-LIB-ree-um). If you’re both the same size (have the same mass), you can sit at equal distances from the center to balance out. If one of you is bigger than the other, the bigger person should sit closer to the center.

With the teeter-totter balanced, you’ll take turns applying force with your legs pushing you up and gravity pulling you back down. And don’t forget: When you’re done playing, make sure the plank is balanced and that you both gently get off at the same time—or one of you will crash down with a thud!

Merrily We Spin Along

A merry-go-round (or roundabout) can make your head spin—literally! As you push off and the platform starts spinning, you're creating circular motion. The harder you kick off, the faster the platform will spin.

Then hold on tight! The spinning platform will create centripetal (sen-TRIH-puh-tul) force that keeps you from flying off as long as you’re holding on. But don’t let go! Let the platform spin to a stop first so you can step off carefully and not feel as dizzy.

Centripetal force also keeps you on your bike around those fast turns!

Gravity Slows You Down—and Speeds You Up

Climbing up the ladder to a slide might feel scary, but sliding down? What a thrill! You can thank gravity for both the scare and the thrill.

Because gravity pulls you down, climbing up can make you feel dizzy and anxious. But that same force is what pulls you down the slide, faster and faster! The higher or steeper the slide, the faster you’ll gain speed as you go down—an effect called acceleration (ack-SEH-ler-AY-shun).

Acceleration on a slide is an effect of gravity. That means that running down a hill in a game of tag or riding down a slope on a bike will speed up your fun!

But before you zip off, remember that gravity is always pulling you down. So while going downhill speeds you up, going uphill will slow you down. You’ll have to work extra hard to run or bike up a hill!

Monkeying Around

Monkey bars can be tricky if you’re just hanging still. That’s because gravity is pulling you down. But when you start swinging, you build up momentum (moh-MEN-tum) as you speed up. Momentum is the mass and speed of a moving object. Once you’ve built up momentum, you can swing to the next bar.

No Fiction in Friction

Friction is a force that slows you down once you are moving. Rough things like grass and carpet have more friction than smooth things like ice and wood floors. Thanks to friction, you can play tag, grip monkey bars, and ride a bike without slipping and sliding.

Soccer players and other athletes increase friction by wearing cleats (or studs) on the bottoms of their shoes. Cleats help their feet grip the field without slipping.

Catch That Momentum!

Throwing a ball isn’t just muscle power—it’s momentum.

When you throw a ball, you’re moving energy from your muscles to the ball. The harder you throw the same ball, the more momentum it has to fly through the air.

Baseball players wear mitts to help absorb the force of the ball when it hits their hands. But you don’t need a mitt to catch a ping-pong ball because it has less mass and less momentum.

Almost Time to Head Home

Every time you bike, spin, swing, or seesaw, God’s amazing forces of nature are at work. In him, “all things hold together” (Colossians 1:17). What a wonderful and joyful God we serve!

When we learn how God's forces of nature work—like gravity, motion, and balance—we can get better at our favorite games and sports. And even more importantly, we can thank God for giving us such fun ways to move and play (1 Thessalonians 5:18).

Force Fun!

How well do you understand natural forces? Test your knowledge by choosing the correct answers.