On the rides at the fair, physics is a scream

Editor’s note: This story originally ran Aug. 28, 2011. But we enjoyed it so much we decided to share it again.

MONROE — It’s an exhilarating experiment into the wonders of science as soon as you hand over your ticket.

The Nitro, the Super Shot Drop Tower, the Zillerator.

Thousands of people will head to the Evergreen State Fair on Sunday to step aboard any one of 41 rides that aim to thrill, terrify or delight.

Each drop, every whirl, every stomach-flipping loop is grounded in basic laws of physics.

Think about it.

The Zillerator, the only full-size roller coaster at the fairgrounds, reaches a maximum speed of 40 miles per hour. While slow by roller coaster standards, it’s still a marvelous lesson in gravity and other physical forces.

On the Super Shot Drop Tower, passengers get lifted 90 feet in the air and then plummet as fast as 47 mph. And what’s keeping them from crashing into the ground is the power of magnetism.

Even something as simple as bumper cars illustrate laws of Newtonian physics.

Every time you scream your head off on a ride, basic principles of physics prove themselves in a demonstration more convincing than any classroom experiment. That’s why Clarence Bakken of Sunnyvale, Calif., has taken his high school physics class to amusement parks over and over during his 35 years as a teacher.

“So many things that happen at an amusement park involve rules that we study in a physics class,” said Bakken, who has written a book about amusement park physics. “On a ride, you can experience them in a powerful but safe way.”

What’s more, your body undergoes physical reactions, in subtle and not-so-subtle ways, triggered by the speeds, turns and terror of amusement rides.

“The rides make all of us fighter pilots,” said James Lee, a doctor of internal medicine at The Everett Clinic. “The gravity force is no different than during high-speed flying.”

Here’s a look at a handful of rides, the science behind them and what happens to you when you ride them.

Zillerator

The roller coaster cars rumble up and down the yellow and green metal rails. Like all typical roller coasters, it has no engine. It’s lifted up that first hill by a chain mechanism and propelled downward by the forces of nature.

Gravity and momentum take it all the way to the end, Bakken said. To understand how this happens, imagine riding a bicycle. You begin by pedaling, but after it reaches a certain speed it will move by itself.

The ride gains what is called potential energy on the way up and uses kinetic energy on the way down, Bakken said. Potential energy comes from gravity. Kinetic energy is the energy of motion.

Some large roller coasters today have launch mechanisms that enable them to go much faster. Kingda Ka at Six Flags Great Adventure in New Jersey, with its top speed of 128 mph, is the fastest roller coaster in the United States. The fastest one in the world, at 149.1 mph, is Formula Rossa in Abu Dhabi.

The most exciting part of roller coaster rides is the dip at the bottom of the first — and tallest — hill. If you were sitting on a bathroom scale at that moment, you would see that you weigh several times what you normally do, Bakken said.

Why don’t you crash through the rails at the bottom and slam into the Earth? The tracks won’t let you. But in physics terms, another force is at play — what’s called the normal force. That’s the force from the ground, or in this case, the tracks, pushing back at you and making you change direction.

Another favorite roller coaster thrill is, of course, the loop-the-loop. The Zillerator doesn’t have one, but it’s a part of the roller coaster experience worth explaining. You’re afraid you’re going to fall out. Guess what? You wouldn’t fall out even if you didn’t have the safety harness holding you in place, Bakken said.

Once you start moving through the loop, inertia is pushing you into the seat of your car and preventing you from falling out. At the same time, the inertia gives you enough energy to go all the way around the circle. Gravity and other forces are involved, too, but let’s not complicate things too much.

Nitro

The Nitro with bright flashing lights sways back and forth like a giant pendulum, swinging as many as 24 people high into the air. As your body reaches that weightless moment at the high point of each swing, your seat spins and your feet dangle in the air.

You experience freefall at the high point of each swing, said Andrew Laszlo, a doctoral student at the University of Washington physics department.

“If you were standing on a scale at this point in the ride, for a moment, it would read zero,” he said. It’s similar to what astronauts experience in space.

For a brief moment on that pendulum, you are weightless. This doesn’t mean you don’t feel the force of gravity: Gravity pulling on you is what makes you start to go down. Weightlessness isn’t the absence of gravity; it’s the absence of that normal force — the force of the ground, your seat or your roller coaster harness pushing back at you, Laszlo said.

The Nitro and other rides apply different forces to your body in order to make it move. You feel all these forces changing while you are on a ride, he said.

Super Shot Drop Tower

The Super Shot Drop Tower looms over the fairgrounds. Passengers are strapped into seats all around the base of the tower. Their feet dangle as they slowly ascend. After a few anxious moments, 90 feet in the air, they plunge back to Earth.

A magnetic brake system stops the lift before it reaches the ground. To understand how it works, think about this experiment you may have conducted in a physics class: Put a piece of copper on the table. Then take a magnet and start moving it back and forth above the copper. A magnetic field will be created, and you will feel the metal resisting.

Copper is one of the metals affected in this way because electrons in the metal move easily and freely. That’s why it’s used for electrical wires.

In the Super Shot Drop Tower, the magnetic field created by this interaction will stop the lift from reaching the ground, Bakken said.

This brake system uses no electricity, so if the power goes out while you are in the Super Shot Drop Tower, you will still stop. Magnetic brakes are preferred over regular brakes because they are virtually foolproof, produce no noise or smell and never touch the ride. The magnet is hidden behind the passenger seating area, and the copper is in special fins located along the tower, Bakken said.

And the drop gives one of the best adrenaline rushes at the fair.

And that’s a key reason why people love these rides. The adrenal glands, located above the kidneys, release the hormone adrenaline.

“Physically, adrenaline rush gives people a sense of immediate well-being,” said Lee, the Everett Clinic Doctor. “Psychologically, facing our fear and overcoming it gives us great satisfaction.”

Bumper cars

The star of many carnivals and fairs, the black, yellow and purple bumper cars are popular with families. What riders probably aren’t thinking about is the fact that they are treated to a firsthand demonstration of Newton’s first law. An object at rest or in motion will remain in its state with the same speed, unless an external force is applied to it.

“If you were way out in deep space, a long, long way away from the tug of the Earth, the moon or the sun, you wouldn’t experience any forces,” Laszlo said. “If you weren’t moving, you wouldn’t move from that spot ever, and if you were moving, you’d just go in a straight line unless some force acted on you.”

When your bumper car begins to move, you also move. When it bumps into another car, your body jerks forward. That’s because your body wants to keep going in its original direction — forward, Bakken said. An external force, which is the seat belt in this case, prevents you from be flying out of your car head first.

“Everyone riding bumper cars should think about why they need to wear seat belts in real cars,” Bakken said.

Gravitron

One of the favorites year after year at the fair is the Gravitron.

While it’s in the shop this year — and missing from the fairgrounds — the popular ride still is a wonder of science.

The ride looks like a spaceship where passengers step inside and then stand along the wall. The Gravitron spins around, 24 times per minute, mushing you against the wall. Soon you’re stuck against the wall.

Why don’t you fall down? Friction is keeping you in place. It’s the force that resists the movement of one surface against another. In this case, friction is created because the wall pushes on you and prevents you from shooting off in a straight line. As the Gravitron spins faster, the wall pushes on you harder.

That’s why the wall is usually made of carpet or rubber material, which creates friction, Bakken said.

If the wall was made of stainless steel, you’d be in serious trouble, Bakken said. Steel is one of the materials that has low friction.

Those prone to motion sickness get uneasy just thinking about the Gravitron.

“The reason we get dizzy is because our inner ear, which is responsible for balance, does not match what we see with our eyes when we are traveling at high speed,” said Lee, The Everett Clinic doctor.

Our ears are equipped with six liquid-filled tubes called semicircular canals. They act like a builder’s level.

These canals give us information about where we are in space. Our eyes also give us information about spatial orientation. With fair rides, the speed at which the world is moving often is faster than what our ears can sense, he said.

Sometimes after we climb out of the Gravitron or another ride, we feel like everything is spinning even though we no longer are. We can feel nausea or even throw up. It’s called vertigo, Lee said.

The physical world is more complicated and has more moving pieces than just this. But this is a rundown on many of the things that happen when you step on the fairgrounds.

And even though you may not need it, make sure your wear your safety harness.

Katya Yefimova: 425-339-3452, kyefimova@heraldnet.com.

Butler takes you for a ride

The carnival that visits the Evergreen State Fair is run by Butler Amusements Inc.

The family-owned company is the largest amusement business on the West Coast and stocks 35 fairs in seven states every year.

It was founded in 1970 by Bud Butler, his wife, Evalyn, and son Butch. Their inaugural carnival was in Mountain View, Calif.

Bud Butler’s love affair with amusement parks started when he operated concessions at carnivals near his hometown in Minnesota.

Butch Butler and his wife have four daughters, all of whom work for the family business together with their husbands.

As a high school graduation present, the couple gave each of their daughters a concession stand with hot dogs and cotton candy, said Andrea Owen, a company spokeswoman who is Butch Butler’s niece.

The unit that visits the Evergreen Fair is run by Butch Butler’s daughter Kris and her husband, Mick Brajevich. A unit consists of rides, games and food.

For more information about the company and its rides, go to www.butleramusements.com.