What does an engineer do? High school students get firsthand experience
This article first appeared in the St. Louis Beacon, June 18, 2013 - Take balsa wood, corrugated plastic, analytical young minds and a basic engineering problem and what do you get?
At Washington University, the result was ingenious solutions to the perennial problem of how to decrease the dependence on fossil fuels for energy and use renewables instead.
The recent exercise was part of Explore Engineering, a program now in its third year, offered by the school of engineering. Thirty 30 students from high schools throughout the St. Louis area come together to learn about what engineering has to offer, then set their minds to forging projects including a prosthetic hand, battling robots and a wind turbine that can generate electricity.
The wind turbine exercise was run by Chad File, who recently earned his Ph.D. in aerospace engineering from Washington U. He set the tone by defining what the discipline is all about, with a quote from Arthur Wellington back in 1887, who said that engineering “is the art of doing that well with one dollar, which any bungler can do with two.”
In room 110 of Jolley Hall on the northern edge of the campus, File told students to break up into four teams of four each and station themselves at tables that featured the wood, plastic, dowels and other materials they would use to create a turbine, plus a large electric fan that would eventually get the project moving.
First, File said, he wanted to give the students a taste for what engineering is all about and how serious the problem is that they would be working on.
“I try to instill the fact that in most areas, people work in teams,” he said of engineering. “It’s not like in other areas, like accounting or something. You will work with the skills of other people.”
Using graphs to show how sharply the use of energy has shot up in the past 60 years, and how small a share – about 1.2 percent – wind-produced energy has in the United States, File ran through the reasons it hasn’t caught on, including costs of building and operating windmills, noise, safety and the NIMBY factor (a lot of people don’t want big machines in their backyards).
Still, he said, “wind blows everywhere, so we should be able to harvest that and drive that number up.”
Using wind to power turbines to produce electricity can be preferable to other methods, he added. How about capturing the power of teenagers?
File said that it would take 46 teens and 650 energy bars a day to pedal exercise-bike generators 8 hours a day, 365 days a year, just to generate the power needed by one U.S. household.
Shaping the blades
After that introduction, the teams were ready to get to work to craft their own turbines. First, File said, they should take about 10 minutes to sketch out the shape of the blades so they would be as efficient as possible.
Brainstorming about the best possible way to proceed, and then making it work, capture the essence of what engineering is all about, he said: starting with a wide range of ideas, some of them seemingly far-out, then deciding which are most practical and deserve to be tried.
“This is what engineers do,” he told the students. “They get together and they talk.”
The only all-female team in the room got ready to do just that.
Samiksha Mailarpwar from Parkway Central High School, Valerie Levine from O’Fallon Township, Aida Bukvic from Gateway STEM and Haley Crosby from Francis Howell sketched out a blade that was straight on one side and curved on the other.
As they and the other teams worked, File reminded them: “Sometimes there are wrong designs, but there is no No. 1 right design.”
The students began assembling the base of their turbines from PVC pipe, and one of them asked File if he could tell them which design would be most efficient. He laughed and replied:
“Don’t ask me about that. I can talk about that for two hours.”
The four girls spent the next half hour or so working with the blades, four from balsa wood and three from corrugated plastic. After sketching, cutting, sanding, taping and angling, they stepped back to check their work. The verdict?
“It looks really cool,” said Valerie.
Aida added: “It does look really awesome.”
Next came the real test – hooking the turbine up to a voltage meter, then turning on the fan and seeing how much electricity was being generated. Would it be enough to run a pump that would send water up through a cylinder and over the top?
The first run started out strong, at over 2 volts, but then fizzled.
“It’s slowing down, which means something is changing,” File said.
Their solution was to add more tape to strengthen the bond between the blades and the dowels.
As shouts of success went up from other tables, the four reattached the blades and tried moving them back and forth to change the angle at which they would catch the wind.
“We’re innovating,” said Aida. “We’re not inventing.”
When one of the plastic blades got caught on the base and the turbine wouldn’t turn, some quick surgery with a saw solved the problem. Finally, as the 90-minute session was nearing the end, the would-be engineers were ready for their final tests.
The voltage meter started out strong and kept climbing. File said 1.7 volts was the critical point to make the water pump work, and the girls watched as the meter moved above 2, then 3, then 4 volts.
The water in the cylinder kept moving up slowly, hesitated as the rising liquid worked to overcome surface tension, then finally overflowed the top of the tube.
So what did the students learn about engineering, besides the flush of victory when a project works like it’s supposed to? As she helped clean up and put the equipment away, Aida summed it up this way:
“It’s more hands on. It’s not boring. And changing something can make a big difference. You need to learn from your mistakes. Teamwork is a huge thing. If we hadn’t learned together, we wouldn’t have gotten anything done.”
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