On a sunny day, a yellow school bus heads to Elver Park in Madison, Wisc. The seventh graders inside are excited to launch the rockets they’ve built in class.
At the park, the students find their assigned flag posts, armed with their rocket, notebook, pencil and angle finder. Two at a time, they march to the launch pad and prepare their rocket for take-off. They wait for their teacher’s signal to start the countdown: 5, 4, 3, 2, 1… GO!
With the angle finder and a little math, they estimate each rocket’s maximum height. They calculate how their rocket fared against 90 others made by their classmates and teacher.
“With the rocket unit, I teach the basic principles of physics and motion,” explains David Ropa. He teaches science at Spring Harbor Middle School and embraces learning by doing. That includes taking math and science into the park.
“Kids, like all humans, are doing science all the time,” says Ropa. They explore the world through play, he adds, whether it’s stacking toys or building bike ramps. They have a hypothesis. They set up a test. They analyze the results. Then they adjust their strategy.
The tools his students use at school, says Ropa, are the same as those that many adults use at work. Some of these adults wear a white lab coat and carry a business card with the word “scientist.” Most don’t.
Chefs, musicians and gardeners often use the scientific method, though they may not call it that. Their jobs — and many more — apply textbook principles of science in the real world.
The science of cooking
J. Kenji Lopez-Alt is the chef at a German-inspired beer hall and restaurant in San Mateo, Calif. He also is culinary director for Serious Eats. That’s an award-winning blog about “anything food and drink.” In its Food Lab section, Lopez-Alt “unravels the mysteries of home cooking through science.” He also wrote a bestselling book on that topic.
At age 18, Lopez-Alt wanted to become a scientist, like his dad and grandpa. He took biology classes at the Massachusetts Institute of Technology in Cambridge. He also worked in a biology lab. But being a scientist soon began to lose its appeal.
“Although I loved biology, I found the day-to-day lab work very boring,” he explains. “I couldn’t see myself doing that for decades.”
Searching for a summer job outside the lab, Lopez-Alt stumbled upon cooking. A Mongolian restaurant needed a prep cook to start right away. At that job, he fell in love with cooking. Although he graduated college with a degree in architecture, he kept returning to the kitchen. He worked his way up the ranks in several restaurants.
The more he cooked, the more he started to question the assumptions behind his recipes. Much of cooking is tradition. But, he wondered, are there scientific reasons for preparing food the way we typically do?
In his restaurant jobs, Lopez-Alt didn’t have time to pursue that question. That changed when he started working at Cooks Illustrated. This cooking magazine features detailed recipes that describe how they were tested and tweaked. Lopez-Alt started as a test cook and writer. Soon, he became the magazine’s science advisor.
In that role, “I could finally answer all these questions that had been building up in my head during my years as a line cook,” says Lopez-Alt. He especially likes to apply his knowledge of physics and chemistry to home cooking.
Lopez-Alt still creates many new recipes by questioning assumptions. For example, people often boil potatoes in plain, pH-neutral tap water. But roast potatoes taste best with a crunchy outside and a creamy, flavorful center. To achieve that taste, Lopez-Alt adds a little baking soda to the water. That raises its pH. The water is now slightly basic (alkaline), instead of neutral.
That helps because the cell walls in fruits and vegetables contain pectin. This starch breaks down more easily in alkaline water. Thus, the outer surface of potato chunks boiled in that water gets softer while the inside stays firm. That soft surface becomes deliciously crispy when coated with oil and roasted on a baking sheet.
Another longstanding tradition is to sear a steak in a pan, then finish it in a hot oven. Lopez-Alt prefers his “reverse sear” method. He starts with slowly heating the meat in a warm oven (275° Fahrenheit; 135° Celsius). The sear comes last. Science explains why that produces a more tender piece of meat with an evenly browned crust.
First, by the time the steak’s center reaches medium-rare in a hot oven, its outer layers are overcooked. That bull’s eye effect is due to physics. The larger the difference between the temperature of an object (steak) and its environment (oven), the larger the difference inside the object. That’s one of the laws of thermodynamics.
Second, meat contains enzymes that break down its connective tissue in a warm environment. While the meat roasts slowly in the low-temperature oven, those enzymes have time to tenderize it. But if the oven is too hot, it turns off the enzymes.
Third, it takes five times more energy to evaporate a gram of water than to bring it from ice-cold to boiling. (That’s physics again.) Searing the raw meat first wastes energy on drying out its moist surface to produce the brown crust. But searing the meat after the oven has evaporated its moisture browns it more quickly and evenly.
Piano science
Like cooking, music combines art and science. That’s also true when taking care of instruments.
“The process of tuning a piano is a physics lesson in action,” says Don Mitchell. He’s a retired piano technician in Vancouver, Wash. He used to teach at the School of Piano Technology for the Blind.
Mitchell grew up in Oregon in a music-loving family. At an early age, he was fascinated by science. He loves to sing and plays the piano, guitar, banjo, mandolin and bass.
Blind since birth, Mitchell relied heavily on listening to learn to play those instruments. His job combines those listening skills with science. He uses the physics of sound (acoustics), the mechanics of motion and the mathematics of musical scales.
Piano keys are mechanical levers for strings inside the piano. Pressing a key makes a small hammer hit these strings. The moving strings cause molecules in the air to vibrate. The vibration travels through the air as a sound wave.
The length and thickness of the string determine the frequency, or pitch, of the sound wave. Short and thin strings produce high pitches, which we hear as tenor and treble notes. Longer and thicker strings produce lower pitches, which we hear as bass notes.
But short strings don’t make as much sound as long ones. The higher pitches combine up to three strings to make them loud enough to hear. That’s why most pianos have 88 keys and around 230 strings.
To tune a piano, Mitchell uses a wrench to turn metal tuning pins attached to the strings. That changes the strings’ pitch by adjusting their tension and length. But tuning is more than getting each key to produce one specific pitch.
Mitchell has to adjust multiple vibrating strings together so that the intervals between notes match intervals in musical scales. These scales are based on mathematical relationships between pitches. To describe them, scientists measure each pitch in hertz, or vibrations per second. For example, the pitch of the note A above middle C needs to be 440 hertz. The pitch of the note B next to it should be about 494 hertz.
The challenge of tuning is that the interaction of multiple strings is different for each piano. That’s why Mitchell has to combine his math skills with an excellent musical ear. He has to make all the intervals between pitches sound correct. A well-tuned piano has a smooth, rich and pleasing sound, no matter what combination of notes a pianist plays.
When Mitchell repairs a piano, he uses the same strategy as a scientist testing a hypothesis. He changes one part at a time while keeping all others constant. “Eventually, with years of experience, you hear the sound and already have a good idea what’s wrong,” he adds. “That’s especially true for blind people.”
Problem-solving for airplanes
Lynze Price’s childhood dream was to become an astronaut. In the end, she found a more down-to-Earth job: She helps planes fly safely. At Embry-Riddle Aeronautical University in Daytona Beach, Fla., she earned a bachelor’s degree in aviation-maintenance science.
As a corporate aviation technician, she combines her love of physics with her knack for fixing stuff. She calls herself an “aircraft surgeon.” She must diagnose problems and figure out how to solve them.
For example, airplane antennae transmit or receive electrical signals through shielded wires. Those signals help a plane navigate to its destination and communicate with traffic-control.
When an antenna doesn’t correctly sense the airport runway, Price studies the plane’s wiring diagram. It shows all of the plane’s electrical connections. Electrical engineers with advanced degrees designed that system. Price has to locate on the diagram the wire linked to the problem. Then she can hunt down the wire to fix a loose connection or other issue.
Brake valves are another example. The plane’s computer system controls these valves. Computer engineers put that system together. When brakes have issues, Price uses her troubleshooting skills to figure out what’s wrong. Sometimes the brake needs a new valve. Other times, it’s the computer system that needs a small adjustment.
“As an aviation technician, I’m doing some of the same practical things that engineers do,” says Price. “I’m just not the person sitting behind a desk and designing the entire system.”
Caring for plants
Leslie Hunter also uses problem-solving skills to keep a system working well. But she’s in charge of plants, not airplanes. She started her own vegetable garden at age eight. Her parents tilled the ground, but she was in charge of all else.
In college, Hunter discovered horticulture. That’s the science and art of growing fruits, vegetables, flowers and ornamental plants. Today she works in Iowa, at the Greater Des Moines Botanical Garden.
As part of her job, Hunter regularly tests soil pH and levels of nutrients, such as phosphorus and nitrogen. She uses chemistry and soil science to decide which fertilizer will best support which plants. For example, many green leafy plants prefer more nitrogen. But in flowering plants, extra phosphorus is a bloom booster.
From soil science, Hunter knows that evergreens, rhododendrons and azaleas need acidic soil, with a pH below 7. Maples and butterfly bushes prefer alkaline soil, with a pH above 7. In some flowers, pH levels even determine the blooms’ color.
The science of insects (entomology) and of plants (botany) help Hunter control garden pests and weeds. That’s also important for knowing when and how to prune shrubs and trees.
Sometimes, Hunter tests new plant varieties in a garden plot. She uses genetics to understand how plant breeders created these cultivars. That helps her decide if they might be a good fit for Des Moines.
Role playing and role models
In Madison’s Elver Park, the students make their rockets fly as high as they can. That teaches them the physics of flight. It also instills a sense of wonder and hopefulness, says Ropa.
Some kids will never forget that rocket launch. For others, a crime-scene-investigation unit may hook them on science.
“Kids are morbidly curious,” says Ropa. “Just watch them when a dead fish washes up by the lake.”
In a classroom-turned-briefing-room, Chief Detective Ropa introduces a suspected-murder case. There’s a body outline on the floor, complete with autopsy report, fingerprints and a few samples. (Ropa removed images of the dead body from a real report and added fictional names.)
The students use science to solve the case. To understand the reported time of death, they learn how the heart and lungs work. They decide how to use the samples for DNA tests. They figure out how to turn fingerprints and DNA results into a list of suspects.
With their data, the students make hypotheses about who did it and why. Ropa listens to them debate and defend their ideas. For the next two months, he only answers questions as Chief Detective Ropa.
Role models like this can get and keep students interested in science, says Ryan Lei. He is a psychologist at Haverford College in Pennsylvania. His studies show that the language a teacher uses can also make a difference.
Kids stay more confident about “doing science” when their teachers use those words, Lei says. Talking about “being scientists” actually may lower their confidence. The kids in the studies ranged from preschool to late elementary school.
Attitudes toward science and scientists often change as kids mature, says Lei. So do the factors that shape those attitudes. Older students may care more about adult role models than a teacher’s language. But those adults don’t have to be scientists. They just need to model the human curiosity we’re all born with.
Says Hunter, “That’s what scientists really are — very curious people who keep that curiosity going in their jobs.”
Building 3-D printers via trial and error
Maarten van Lier loved to build stuff as a kid. After earning a degree in computer science, he developed software for different businesses. He eventually quit and returned to building physical things — 3-D printers.
These machines assemble objects from computer models by adding one thin layer at a time of plastic or some other “ink.” Van Lier didn’t take any classes in electrical engineering or robotics. He found everything he needed to know on the internet.
He often starts with some component he found on eBay. The rest is trial and error. He comes up with a design idea, tests his hypothesis and observes the results. If it doesn’t work, he analyzes why and starts over. That’s not so different from how a scientist runs experiments.
“I always felt that I used a lot of science but would never call myself a scientist,” says van Lier. Instead, he’s “applying their original ideas to real-world problems.”