When we arrived at Parks College on the campus of St. Louis University, Amy Preiss, our on-site coordinator, and Dr. Scott Sell who conducts research in the areas of tissue engineering and regenerative medicine in the Biomedical Engineering Department greeted us in the lobby.
Amy and Dr. Sell proposed an icebreaker activity to start the day and get everyone in the mood to learn and have fun. Students were given a jumbo marshmallow, popsicle sticks, string, a plastic bag, straws and masking tape and tasked with creating a way to launch their marshmallow from a table to one of two bins, using only one hand. Congrats to the winning team: Isabel L, Sarah, and Jessica!
As we began our time with Dr. Sell, he explained that his work involves creating materials for the human body like cartilage, bones, skin, arteries, which have the mechanical properties to allow them to perform as well as the materials naturally produced by the body. Used in the process are polymers, alginate, hydrogels and scaffolding. Dr. Sell had the students compare the stiffness of materials created when 1%, 2% and 3% alginate was added to calcium chloride. Through this process, we discovered that the higher concentrations of alginate made the tissues more solid. We then added the alginate to calcium sulfate, which reacted more slowly, allowing it to be molded into shapes. With their excellent chemistry prep from CJ, students deduced that the calcium chloride gives up the calcium more easily than the sulfate. We then did several exercises to review these formulas for stress and strain. Finally, we did a lab in which we created three different kinds of alginate hydrogels, determined a way to test their strength and then compared them to fat, bone, brain, cartilage, muscle and skin. This was an exciting hands-on way to better understand what biomedical engineering can look like!
After a delicious Jimmy Johns lunch with two BME female professors and one BME graduate student who shared their backgrounds and advice about pursuing the field, we headed to the new Structural Engineering Lab to learn about Civil Engineering.
Our host, Dr. Carroll and some of his students had the girls guess how many pounds one steel truss that weighs 80 pounds will hold. We were flabbergasted to hear that it will actually hold 16,000 pounds!
In three small groups, we did force and moment problems. For example, when a 200-pound person stands in the middle of a six-foot fiberglass beam, the scales at each end measured 100 pounds. If a person stands one foot from one scale and five feet from the other, then the closer scale holds 5/6 of the weight and the far scale holds 1/6 of the weight. Then, we had two people stand in different positions, calculated the weight on each scale, and tested our calculations. To make it even more interesting, we traded the six-foot beam for a 12-foot beam and the scale was moved to four feet from the end to create a cantilever. We calculated how far a 112-pound person should stand to balance a 200-pound person two feet from the end. Then we tested it. Success! Thank you Mr. Russell! Seniors remembered these as the “elephant” problems, and taught the incoming juniors what they have ahead of them next year! We then moved from one dimension to two dimensions and were able to estimate the weight at each of the scales on the four corners of a rectangular frame.
Finally, divided into groups of four or five, the students were challenged to build a tower with KNEX. It had to be 18 inches tall and hold 15 pounds. Kanisha, Abby, Kaitlyn, and Isobel had the first KA-BOOM! But they quickly analyzed their tower and started over to correct the problems. Every group gained momentum as they tested their designs and made improvements. We all agreed that failing along the way is how we learn! This was a really fun and instructive team building effort and a great day at SLU with lots of variety and activity! Looking forward to visiting Watlow’s Advanced Technology Center tomorrow!