Research Log: How Our Town Clears Snowy Roads
1After a big storm last winter, Priya and Jonah woke up to roads that were already clear. They wondered how that happened, so they chose the town's snowplow crews as the topic of their research project. They split the topic into three parts: the science of salt, the plan for which roads get cleared, and the trucks and tools the crews use.
2Source 1: an article in a children's science magazine. Priya read an article called "Why Salt Melts Ice." It explained that salt lowers the temperature at which water freezes. When salt mixes with ice on a road, the ice can melt even on a day below freezing. The article also said that salt does not work as well on very cold days, so some crews spread sand to give tires better grip.
3Source 2: a video on the town's public works website. Jonah watched a short video made by the town. It showed a truck spraying salty water, called brine, on the roads a day before a storm. The brine helps keep snow from sticking. Then the video showed a map of plow routes. Main roads, bus routes and the road to the hospital are cleared first. Small side streets come later.
4Source 3: a visit to the town garage. With their teacher, the partners visited the garage and met Ms. Haddad, a plow driver. She showed them the wide steel blade on the front of her truck and the spreader in the back that tosses out salt. "Before every storm, we check each truck from top to bottom," she said. She told them that during a long storm, drivers often work through the night. She also agreed with the magazine article: on the coldest nights, her crew adds sand to the salt.
5Back at school, the partners compared their notes. They were glad to see that two sources agreed about sand. Each source had taught them about a different part of the topic, but one question was still left. None of their sources told them where the town gets all of its salt. They wrote that question at the top of a new page.