Polar vortex! Bomb cyclone! Blizzard! All of these terms signify snowy weather and below freezing temps. Our 8th grade students recently conducted an experiment in science class to help combat one of the major issues during winter storms—providing warmth to the homeless. On a shoestring budget of $5.00, students designed devices that utilized a chemical reaction to provide temporary heating for homeless individuals.
Students split into small groups to begin researching the core issue for their project: hundreds of thousands of people are homeless in the United States, and more than 100,000 of those are children. Hypothermia can set in at 50°F, but many homeless shelters do not open their doors until the temperature drops much lower. Is it possible to design and create a prototype for a portable heater that stays warm for at least one minute utilizing a chemical reaction, all for under $5.00? The results of 8th grade's projects answered this question with a resounding "yes!"
Ms. Elizabeth Phillips, Regis 6th and 8th grade science teacher explained the motivation behind the project. "In our current unit, 8th grade is studying thermal energy in chemical reactions, specifically exothermic and endothermic reactions," she said. "I thought this engineering solution would be a good way to sum up what 8th grade learned. They had to use their knowledge of chemical reactions learned in both this unit and past units to build a prototype device. This really brought a lot of different units together." This project also tied in perfectly with Goal III: a social awareness that impels to action, she added.
"[We] found a video of a portable heater online," said Joshua Caldwell, 8th grade student, "and they put a lot of calcium chloride in a gallon bag. We didn't want to waste so much calcium chloride." Caldwell's group, like many others, created a chemical reaction by mixing calcium chloride with water, which produced an exothermic reaction to heat up the water. His group placed calcium chloride in a small Ziploc bag and then placed this bag in a larger Ziploc containing water. Once they sealed the large, outer bag, they squeezed the bag to burst the inner bag containing the calcium chloride. The chemical reaction started almost immediately, and the water stayed warm for at least a minute.
Another group used the same approach as Caldwell's, but created a pouch to surround their device so that it would be more comfortable to hold when it was hot. A third group utilized water and calcium chloride too, but placed it in an empty soda can with vent holes instead. "The boys were very engaged in this project!" said Ms. Phillips. "I never had to ask them to stay on task because they never stopped working! Alex Fuentes even took it upon himself to work on this over the weekend (and this was an in-class project) so that he could really build something that could make a difference."
Each of the student projects passed the one minute test, and most explained that if they had a bigger budget, they could create devices that would maintain heat for a much longer time. This practical to use knowledge of chemical reactions could have long-lasting benefits for those in cold climates.