By Mrs. Jennifer Aldridge (USACE)February 28, 2013
WIESBADEN, Germany -- In honor of National Engineers Week, U.S. Army Corps of Engineers Europe District employees presented structural engineering, alternative energy and fire-protection concepts to Department of Defense Dependents Schools-Europe students Feb. 19-21 at Wiesbaden Middle School.
Lawrence Carabajal, a district structural engineer, presented a bridge-building lesson to eighth-grade science and math students. Carabajal used a hands-on approach, constructing a Leonardo da Vinci-designed wooden bridge for students to test and re-create.
"What engineers love doing is building things and testing them, so let's do it," Carabajal said as he assembled the self-supporting arch bridge in front of a 46-student audience.
Once the bridge was constructed, students were eager to test the capacity by adding textbooks, two at a time, to determine the applied load the structure could hold. Volunteers loaded the bridge with 20 textbooks until an audible crack replaced the silence in the school foyer.
"Wow! There went something. What just cracked?" said a member of Elaine Young's eighth-grade science class.
A few seconds later, the structure collapsed.
"Our bridge has reached its limit," Carabajal said.
Due to excessive weight, the bridge failed and needed to be rebuilt, he explained. Carabajal asked the class to suggest a method to strengthen the bridge. As a clue, he described the weakness of the previous bridge design.
"On our previous arch bridge, the ends were translating or going outwards. For arch bridges you don't want the ends translating. You want them pinned or fixed," he said.
An engaged student's hand popped up in the air; he said reinforcement was the answer to strengthening the bridge.
"This guy is smart," Carabajal said.
Using their feet, students created abutments to reinforce the new bridge, causing the arch to resist through compression and withstand a greater applied load than the previous bridge. The demonstration provided a real-world lesson on compression versus tension, a concept critical to bridge design and construction.
"This is a practical application of the learning taking place in the classroom," said Millicent Dixon, a Wiesbaden Middle School math and resource management teacher. "We need to use math to do this, to build this structure."
For teachers, it is always a challenge to explain how classroom lessons translate into reality, Dixon said. The bridge-building exercise provided students tangible examples of applied math and science.
David Williams, an eighth-grade student who fancies math, said the structural engineering exercise was a good way to learn about bridges.
"At first, it looked like a jigsaw puzzle and I thought, 'Wow, how do you make it stand?'" Williams said.
As the presentation progressed, Carabajal explained how the arch bridge transferred the weight of the bridge and its load to the abutments or reinforcements at either end. He also explained that there are four main types of bridges -- beam, suspension, truss and arch. During the workshop, Dixon saw interest gleaming in her students' eyes.
"Experiences like this with our community motivate our students to learn. The more hands-on engagement, the more real and accessible engineering seems," Dixon said.
When Carabajal was initially approached to volunteer for Engineers Week, he was hesitant and unsure if he was the right presenter for the audience.
"I was skeptical about presenting to middle school students, but after 10 minutes, they were completely involved," he said.
The students enthusiastically raised their hands, asked good questions and volunteered to build, load and measure the bridge. The hands-on exercise allowed students to touch, feel and break the structure.
"I hope they realized engineering is fun and not only practiced by guys with pocket protectors and thick glasses," Carabajal said.
According to Dixon, engineering presentations like this help increase students' retention.
"I see a student who I can't get to pay attention for five or 10 minutes in class and he has been engaged the entire time," she said.
In other words, getting students excited about engineering in middle school or even earlier is advantageous. Frequent exposure to engineering activities and professional engineers is key to attracting students to the field, Dixon said.
"I remember being a student and thinking all engineers went to [Massachusetts Institute of Technology]. For me it seemed unattainable," Dixon said. "But the more experience [my students have] with people in this field the better.
"They see their teachers every day so they want to be teachers. They see athletes on television, so they want to be athletes. They need to see people in science and technology to get them interested in these fields."
As a sponsor, Europe District works with Wiesbaden Middle School teachers and administrators to engage students throughout the year. In addition to Engineers Week, district volunteers connect with WMS via videoconferencing lessons, Earth Day activities and Take Our Daughters and Sons to Work Day. At USACE, it is a priority to attract students to science, technology, engineering and math, or STEM, through outreach programs.
"Our country is in dire need of more scientists and engineers," Carabajal said. "The president has this STEM initiative because so much of the work is being sent overseas. We have to educate [students] and keep that work in our country."
Preparing American students for tomorrow's STEM jobs is a top priority for President Barack Obama. In his 2013 State of the Union, Obama focused on education and announced the creation of an elite STEM Master Teacher Corps to better equip students "for the demands of a high-tech economy." He also highlighted the importance of school-employer partnerships, much like the WMS-Europe District affiliation.
As Carabajal's bridge-building presentation drew to a close, he made a plea to the students, "Please consider engineering as a career field."
Today, STEM jobs are growing at a rate three times as fast as non-STEM jobs, and by 2018 they are projected to grow by 17 percent, according to the U.S. Department of Commerce.
"It may not be the most glamorous job, but it brings in a steady income," Carabajal said.