The Sound of Science - 'Science of Salt'
Becky: You're listening to The Sound of Science I'm WNIJ. I'm Becky with NIU Steam.
Newt: And I'm Newt.
Becky: Despite a warmer winter so far, there's still a chance of snow. And if there's snow, there's bound to be a driveway to shovel and ice to avoid.
Newt: I've always wondered if there was a big difference between table salt and the stuff we scatter on the ground keep pedestrians from slipping. As it turns out, the answer is yes and no.
Becky: There are three main places we scatter salt, on food, on sidewalks and on the roads. The salt for each spot has different goals. On the road, the salt usually only encounters tires, other tires and more tires. But on sidewalks there are many more forms of traffic.
Newt: When I walk my beautiful dog, Bean, I don't want his sensitive paws to get injured or for him to get poisoned by licking his paws because of the salt used against the ice. While salt can be sourced from seawater, we're going to focus on the stuff that comes from halite, which is the mineral form of sodium chloride. Halite is mined from the Earth and if the desired end result is table salt, it is purified of impurities, dissolved in water, filtered, and then evaporated back into a solid form. This salt is edible.
Becky: But the salt we use on the streets doesn't need to be fit for human consumption. In fact, we strongly discourage you from trying to lick this stuff. Road salt is not purified and, depending on the producer, some of this salt has additives to keep it from clumping and becoming useless in storage. Over the winter of 2020 to 2021. The state of Illinois use 522,000 tons of salt and it just makes more sense to buy in bulk and use as needed.
Newt: Some of the salt we use on sidewalks is designed to be gentle on animals. His salt is mixed with another mineral like magnesium or calcium. This does impact how fast the salt will melt the ice, but most people can usually spare a few minutes to let the salt do its job. There are still some concerns about animals ingesting the composition, but there doesn't seem to be a perfect solution yet.
Becky: This has been The Sound of Science on WNIJ, where you learn something new every day.