Summertime Fun Relies on Engineering

For some people, there is no better time of year than summer, when school is out, the days are long, and opportunities abound for getting away from it all. But even when it’s time to kick back and relax, mechanical engineers have worked to make summertime better. Engineers designed most products synonymous with fun in the sun, and they work in the factories to make sure they are built to the right specification.

Here are five summer icons that depend on the work and wisdom of engineers.
 

Roller coasters

The earliest ancestors of the roller coaster were slides made on mountains of ice that sleds would glide down. (In some languages, roller coasters are called “Russian mountains.”) To create an all-weather attraction, wheeled carts replaced the sleds in the early 1800s, and a set of rails built on a wooden framework took the place of the mountains of ice. The first roller coaster that had all the hallmarks of today’s rides—cars drawn up by chains to the top of lift hills and then set free to allow gravity to carry them along a track in a continuous circuit—was the Gravity Pleasure Road at Coney Island in 1885.

Today, most roller coasters are made of steel, and are carefully designed to provide safe thrills with loops and corkscrew inversions while operating only under the force of gravity. Unlike conventional trains, which have steel wheels riding directly atop rails, roller coasters also feature wheels that run alongside and under the rails to keep the cars from flying off the tracks. Good thing, too, as some coasters lift their cars to heights of more than 30 stories.
 

Wave pool

Not everyone who wants to frolic in the waves can make it to the beach, so engineers have found ways to bring the rollicky ocean inland. Some examples date to the early 20th century and created waves by lifting and lowering pontoons.

The Big Surf Waterpark in Tempe, Ariz., was the first of its kind when it was opened in 1969; pumps lifted water into large holding tanks that would then spill all at once into a lagoon, producing waves large enough to surf. (Big Surf, which closed during COVID, is an ASME Engineering Landmark.) Other large wave pools rely on this system, including Siam Park in the Canary Islands which holds the record for producing 11-foot waves.

Take the Quiz: What Do You Know About the Big Surf Water Park?
 

Super Soaker

There’s no better way for energetic kids to cool off than an old-fashioned water fight. And the weapon of choice, the Super Soaker, has a distinct engineering pedigree. In 1989, NASA engineer Lonnie Johnson had built an experimental refrigeration system in his bathroom, and watched as pressurized water shot a powerful stream across the room. He realized that effect could be the basis of a great toy. Johnson built a prototype from plastic pipe, rubber sealing rings, and a two-liter soda bottle.

The reservoir in the Super Soaker is key. As the users pump air into the toy, it builds up in the reservoir and the pressure increases. When users pull the trigger, the pressurized air pushes on the water with tremendous force, shooting it out the toy at great speed.

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Cookout (propane tanks)

Some food tastes best when it is cooked over an open flame or hot coals. Charcoal grilling has its fans, but propane grills are generally considered faster and easier to start and cleaner to use. Since propane is a gas under ambient conditions, it is transported and stored under pressure in strong steel cylinders. In fact, ASME specified the standards for large propane tanks—a size generally used to supply a home or building—while the cylinders used for portable grills are designed to meet other standards.

It’s not just the tank, though. The valves and connectors that carry the propane from the cylinder to the burners also meet tough standards for safe operation.
 

Air conditioning

Sometimes it’s just too hot to spend the summer days outdoors, but engineers can make staying inside pleasant. Air conditioning takes advantage of some basic principles of mechanical engineering, such as thermodynamics, heat transfer, and fluid mechanics, to remove heat from interior spaces. (It moves it to the outside, so while AC cools your house it increases the outdoor temperature ever so slightly.) The basic concept compresses a fluid to raise its temperature, let that hot fluid give off some of its energy to the outside, then bring it back indoors and expand it to lower its temperature, where it then absorbs some of the indoor heat.

Engineers had built rudimentary compression-based refrigeration systems for making ice in the 1900s, but Willis H. Carrier built the first air conditioner in 1901. It took nearly 50 years before the units were miniaturized enough to fit in windows, and the use of AC took off in the 1960s. Today, some 87 percent of U.S. homes have air conditioning, which ought to make the vast majority of Americans grateful for engineers.

Jeffrey Winters is editor in chief of Mechanical Engineering magazine.