Problems with ‘the scientific method’

In Connecticut, first-graders load up toy cars with different amounts of mass, or stuff, and send them racing down ramps, rooting for their favorites to travel the farthest. In Texas, middle school students sample seawater from the Gulf of Mexico. And in Pennsylvania, kindergarten students debate what makes something a seed.

Though separated by miles, age levels and scientific fields, one thing unites these students: They are all trying to make sense of the natural world by engaging in the kinds of activities that scientists do.

You might have learned about or participated in such activities as part of something your teacher described as the “scientific method.” It’s a sequence of steps that take you from asking a question to arriving at a conclusion. But scientists rarely follow the steps of the scientific method as textbooks describe it.

“The scientific method is a myth,” asserts Gary Garber, a physics teacher at Boston University Academy.

The term “scientific method,” he explains, isn’t even something scientists themselves came up with. It was invented by historians and philosophers of science during the last century to make sense of how science works. Unfortunately, he says, the term is usually interpreted to mean there is only one, step-by-step approach to science.

That’s a big misconception, Garber argues. “There isn’t one method of ‘doing science.’”

In fact, he notes, there are many paths to finding out the answer to something. Which route a researcher chooses may depend on the field of science being studied. It might also depend on whether experimentation is possible, affordable — even ethical.

In some instances, scientists may use computers to model, or simulate, conditions. Other times, researchers will test ideas in the real world. Sometimes they begin an experiment with no idea what may happen. They might disturb some system just to see what happens, Garber says, “because they’re experimenting with the unknown.”

The practices of science

But it’s not time to forget everything we thought we knew about how scientists work, says Heidi Schweingruber. She should know. She’s the deputy director of the Board on Science Education at the National Research Council, in Washington, D.C.

In the future, she says, students and teachers will be encouraged to think not about the scientific method, but instead about “practices of science” — or the many ways in which scientists look for answers.

Schweingruber and her colleagues recently developed a new set of national guidelines that highlight the practices central to how students should learn science.

“In the past, students have largely been taught there’s one way to do science,” she says. “It’s been reduced to ‘Here are the five steps, and this is how every scientist does it.’“

But that one-size-fits-all approach doesn’t reflect how scientists in different fields actually “do” science, she says.

For example, experimental physicists are scientists who study how particles such as electrons, ions and protons behave. These scientists might perform controlled experiments, starting with clearly defined initial conditions. Then they will change one variable, or factor, at a time.  For instance, experimental physicists might smash protons into various types of atoms, such as helium in one experiment, carbon during a second experiment and lead in a third. Then they would compare differences in the collisions to learn more about the building blocks of atoms.

In contrast, geologists, scientists who study the history of Earth as recorded in rocks, won’t necessarily do experiments, Schweingruber points out. “They’re going into the field, looking at landforms, looking at clues and doing a reconstruction to figure out the past,” she explains. Geologists are still collecting evidence, “but it’s a different kind of evidence.”

Current ways of teaching science might also give hypothesis testing more emphasis than it deserves, says Susan Singer, a biologist at Carleton College in Northfield, Minn.

A hypothesis is a testable idea or explanation for something. Starting with a hypothesis is a good way to do science, she acknowledges, “but it’s not the only way.”

“Often, we just start by saying, ‘I wonder’“ Singer says. “Maybe it gives rise to a hypothesis.” Other times, she says, you may need to first gather some data and look to see if a pattern emerges.

Figuring out a species’ entire genetic code, for example, generates enormous collections of data. Scientists who want to make sense of these data don’t always start with a hypothesis, Singer says.

“You can go in with a question,” she says. But that question might be: What environmental conditions — like temperature or pollution or moisture level — trigger certain genes to turn “on” or “off?”

The upside of mistakes

Scientists also recognize something that few students do: Mistakes and unexpected results can be blessings in disguise.

An experiment that doesn’t give the results that a scientist expected does not necessarily mean a researcher did something wrong. In fact, mistakes often point to unexpected results — and sometimes more important data — than the findings that scientists initially anticipated.

“Ninety percent of the experiments I did as a scientist didn’t work out,” says Bill Wallace, a former biologist with the National Institutes of Health.

“The history of science is full of controversies and mistakes that were made,” notes Wallace, who now teaches high school science at Georgetown Day School in Washington, D.C. “But the way we teach science is: The scientist did an experiment, got a result, it got into the textbook.” There is little indication for how these discoveries came about, he says. Some might have been expected. Others might reflect what a researcher stumbled upon — either by accident (for example, a flood in the lab) or through some mistake introduced by the scientist.

Schweingruber agrees. She thinks American classrooms treat mistakes too harshly. “Sometimes, seeing where you made a mistake gives you a lot more insight for learning than when you got everything right,” she says. In other words: People often learn more from mistakes than from having experiments turn out the way they expected.

Practicing science at school

One way teachers make science more authentic, or representative of how scientists work, is to have students do open-ended experiments. Such experiments are conducted simply to find out what happens when a variable is changed.

Carmen Andrews, a science specialist at Thurgood Marshall Middle School in Bridgeport, Conn., has her first-grade students record on graphs how far toy cars travel on the floor after racing down a ramp. The distance changes depending on how much stuff — or mass —the cars carry.

Andrews’ 6-year-old scientists perform simple investigations, interpret their data, use mathematics and then explain their observations. Those are four of the key practices of science highlighted in the new science-teaching guidelines.

Students “quickly see that when they add more mass, their cars travel farther,” Andrews explains. They get the sense that a force pulls on the heavier cars, causing them to travel farther.

Other teachers use something they call project-based learning. This is where they pose a question or identify a problem. Then they work with their students to develop a long-term class activity to investigate it.

Three times a year, Lollie Garay and her middle school students at the Redd School in Houston storm onto a southern Texas beach.

There, this science teacher and her class collect seawater samples to understand how human actions affect local water.

Garay has also partnered with a teacher in Alaska and another in Georgia whose students take similar measurements of their coastal waters. A few times each year, these teachers arrange a videoconference between their three classrooms. This allows their students to communicate their findings — yet another key practice of science.

For the students “Completing a project like this is more than ‘I did my homework,’“ Garay says. “They’re buying into this process of doing authentic research. They’re learning the process of science by doing it.”

It’s a point other science educators echo.

In the same way that learning a list of French words is not the same as having a conversation in French, Singer says, learning a list of scientific terms and concepts is not doing science.

“Sometimes, you do just have to learn what the words mean,” Singer says. “But that’s not doing science; it’s just getting enough background info [so] that you can join in the conversation.”

Even the youngest students can take part in the conversation, notes Deborah Smith, at Pennsylvania State University in State College. She teamed up with a kindergarten teacher to develop a unit about seeds.

Rather than reading to the children or showing them pictures in a book, Smith and the other teacher convened a “scientific conference.” They broke the class into small groups and gave each group a collection of small items. These included seeds, pebbles and shells. Then the students were asked to explain why they thought each item was — or was not — a seed.

“The kids disagreed about almost every object we showed them,” Smith says. Some argued that all seeds have to be black. Or hard. Or have a certain shape.

That spontaneous discussion and debate was exactly what Smith had hoped for.

“One of the things we explained early on is that scientists have all kinds of ideas and that they often disagree,” Smith says. “But they also listen to what people say, look at their evidence and think about their ideas. That’s what scientists do.” By talking and sharing ideas — and yes, sometimes arguing —people may learn things they couldn’t resolve on their own.

How scientists use the practices of science

Talking and sharing — or communicating ideas — recently played an important role in Singer’s own research. She tried to figure out which gene mutation caused an unusual flower type in pea plants. She and her college students weren’t having much success in the lab.

Then, they traveled to Vienna, Austria, for an international conference on plants. They went to a presentation about flower mutations in Arabidopsis, a weedy plant that serves as the equivalent to a lab rat for plant scientists. And it was at this scientific presentation that Singer had her “aha” moment.

“Just listening to the talk, suddenly, in my head, it clicked: That could be our mutant,” she says. It was only when she heard another team of scientists describe their results that her own studies could move ahead, she now says. If she had not gone to that foreign meeting or if those scientists had not shared their work, Singer might not have been able to make her own breakthrough, identifying the gene mutation she was looking for.

Schweingruber says that showing students the practices of science can help them to better understand how science actually works — and bring some of the excitement of science into classrooms.

“What scientists do is really fun, exciting and really human,” she says. “You interact with people a lot and have a chance to be creative. That can be your school experience, too.”

Power words

 

philosopher A person who studies wisdom or enlightenment.

linear In a straight line.

hypothesis A testable idea.

variable A part of a scientific experiment that is allowed to change in order to test a hypothesis.

ethical Following agreed-upon rules of conduct.

gene A tiny part of a chromosome, made up of molecules of DNA. Genes play a role in determining traits such as the shape of a leaf or the color of an animal’s fur.

mutation A change in a gene.

control A factor in an experiment that remains unchanged.