Students from Dahlgren School escaped their classrooms but continued their studies as part of Job Shadow Day on Feb. 4, when they participated in demonstrations and experiments with two Dahlgren science, engineering, technology and math (STEM) professionals.
First, the students learned how science explains the world around them in a series of presentations by Brian Dillon, a computer scientist assigned to the Naval Surface Warfare Center Dahlgren Division. Later, the sixth, seventh and eighth graders met with Brenna White, storm water program manager at Naval Support Facility Dahlgren, for a firsthand look at Dahlgren’s newly constructed storm water wetland. There, they took water samples and learned how plants and microorganisms cleanse storm water runoff before it enters the Chesapeake Bay.
The event began at Dahlgren’s Community House with Dillon’s enthusiastic presentation about science’s explanation for phenomena great and small. Many of those explanations can be discovered through relatively simple experiments at home, though Dillon began the presentation with words of caution. “Whenever you do science at home, check with an adult to see if the experiment is dangerous,” he advised. “If you are doing science, you need to stand back and wear protective gear.”
Most of Dillon’s experiments touched on the ways the human brain perceives senses. He began by discussing the “outmoded” theory that different parts of the tongue sense different kinds of tastes-sweet, savory, sour, salty or bitter. He encouraged students to look in the mirror while placing a piece of clear plastic wrap over their tongues.
“What you’ll see are big dots surrounded by little dots,” said Dillon. “The big dots are actual taste buds. Those are the things that sense taste and they are the same all over your tongue. There are no specific regions of the tongue that [taste] this or that, but if you have more of them, you taste things more intensely.”
What humans think of as their sense of taste is also affected by their sense of smell. To illustrate, Dillon chose an eighth grader, Libbie, whose dislike of spicy food suggested a sensitive palate, to do a blind taste test while holding her nose. To the surprise of everyone, Libbie guessed the substance was garlic, when in fact it was cinnamon.
Though Dillon’s experiments delighted, he again emphasized the importance of safety when conducting scientific experiments and cited Pierre and Marie Curie, pioneers in the study of radioactivity, as an example. “Just in time to win the Nobel Prize, they found Pierre was dying,” he said. “So they experimented some more and found that he was dying because of the experiments. They were dealing with radioactive things and it eventually killed both of them.”
The Curies, of course, had no idea that the experiments they conducted were so dangerous, but science has learned from their experience. “There are lots of experiments that people try and they go through rigorous safety protocols to make sure they won’t get hurt,” said Dillon.
Dillon stressed that such precautions must be followed at all times and offered his own cautionary tale. The group was riveted by Dillon’s story about the time he tried to microwave an egg, with explosive results.
While caution is required, Dillon encouraged the students’ to nourish their curiosity. “What you see, what you perceive, makes the biggest scientific discoveries,” he said. “What you will hear, what you will feel, what you will taste and touch; those are the things that will lead to Nobel Prizes.”
Dahlgren’s newly constructed storm water wetland provided students an example of how scientific inquiry can solve real-world problems. It was scientists, of course, who discovered how plants and microorganisms use up and break down chemicals like nitrogen and phosphorus through metabolism. Excessive amounts of those chemicals in bodies of water, however, become pollution. With some thoughtful engineering, plants and microorganisms can be harnessed to reduce the amounts of pollutants in the water. That is the purpose of Dahlgren’s new storm water wetland.
White used an impromptu math discussion to highlight the scope of work involved in the wetland’s construction. “Does anybody know what a cubic yard is?” she asked. “A cubic yard is 27 cubic feet-three feet by three feet by three feet. That excavator, the big orange truck with the bucket, if it takes a heaping scoop [of soil], that is about one cubic yard. So the excavator driver had to do about 10,000 scoops of his bucket onto a truck to get [the soil] off base.”
The figure elicited wows from the students.
The land and water features of the wetland, a result of all that work, help nature remove pollutants. “We need that water volume on site to achieve the treatment we’re looking for,” said White.
The students helped White check the status of the new wetland by examining water samples at Dahlgren’s water treatment facility, checking the water’s pH and looking for microorganisms with microscopes. White also showed students several features of the lab, such as desiccators and de-ionized water that is used to clean equipment.
White asked the students if de-ionized sounded like a good drink. The students wisely answered no.
“Smart people,” White responded, smiling. “Water naturally craves to have ions in it, so if you drink de-ionized water, it’s going to pull ions out of you.”
Once everyone had a chance to look for some very small, but very important critters from the wetland under the microscope, the students returned to Dahlgren School. The students plan to return in the spring to help plant the wetland.
Ann Doyle, science teacher for sixth, seventh and eighth grade, discussed how important such experiences are in helping her students discover their academic strengths, interests and dreams for the future.
“The learning environment should be equitable, supportive, include high expectations, be well managed, provide feedback, active, and of course full of technology,” she said. “But if you really spend time thinking a bit deeper, the people here at Dahlgren provide us with an amazing real-world learning environment by offering so many rich opportunities to help our students connect content in the classroom to real-life experiences.”
Doyle thanked all who made Job Shadow Day possible. “Our students are given a chance to engage in discussions and hands on learning activities with creative, resourceful people who are passionate about what they do in the world of science,” she said. “People like Brian Dillon, who is willing to put together a morning of interesting science content along with real world experiences made us really think about science in way we can understand it. We will never forget about eggs and microwave ovens!”
Doyle added thanks for White. “Brenna White’s contagious excitement about the storm water wetland on base led students to want to know more about it and become part of the community effort,” she said. “Brenna is coming to our classroom later this week with water you don’t want to drink so we can observe live organisms under a microscope. You can’t find a better active learning environment than our own community!”