Why do They Put Salt on Icy Roads?
During winter, when temperatures drop, and snow or ice begins to form on roads, driving can become hazardous. This is why people use salt on the roads during freezing conditions and snowstorms. But have you ever wondered why do they put salt on icy roads? In this article, we’ll explain why salt is so effective at melting ice, how it works, and why it’s the go-to solution for treating icy roads.
Salt and Ice
Salt is used on icy roads because it makes ice melt faster. Under normal conditions, water freezes at 32°F (0°C). Water turns to ice when the temperature drops below this level. However, when salt is spread on ice or snow, it lowers the freezing point of the water. This is called freezing point depression. Specifically, salt breaks down the ice structure and melts at a lower temperature. For example, if the temperature is around 25°F (-4°C), salt can melt the ice, making the road safer and less slippery.
Working of Salt on Icy Roads
Salt works by dissolving into the water on the surface of the ice. Once salt comes in contact with the ice or snow, it dissolves into the tiny amount of water on the surface, even in minus temperatures. Then, brine is formed. This brine solution, a mixture of salt and water, has a much lower freezing point than regular water and will begin to melt. This is why roads treated with salt often clear up during and after a snowstorm. Salt helps break the bond between the ice and the road surface, allowing the snow and ice to be removed or melt faster.
Reason for Using Salt and Not Other Materials
We might wonder, “Why do we only use salt to melt ice?” We can use sand or water to combat icy and slippery roads. While sand can provide traction, it doesn’t melt the ice. Sand provides friction to the objects and prevents slipping. But it doesn’t stop ice formation. Similarly, water can help in some cases, but it doesn’t lower the freezing point of ice as salt does, so it won’t melt the ice in cold weather.
Salt is particularly effective because it directly interacts with the surface of the ice, lowering the freezing point and melting ice. While other chemicals can be used, such as calcium chloride and magnesium chloride, salt is more widely available and affordable, making it the most common choice for treating icy roads.
The Science Behind Salt and Ice Melting
When salt is applied to ice, the molecules in the salt begin to break down the ice’s structure. This is a chemical reaction. The sodium and chloride ions from the salt break up the ice’s solid structure, making it easier for the ice to melt into water. This process makes the ice melt quickly and prevents it from forming again by keeping the ice’s temperature lower than its normal freezing point.
However, salt is most effective when temperatures are not too low. The optimal temperature range for salt to work on icy roads is between 20°F (-6°C) and 32°F (0°C). When temperatures drop lower than 20°F, salt gradually loses its ability to melt ice. Alternative products like calcium chloride or sand might be used in extremely cold weather because they can work at lower temperatures.
Effectiveness of Salt in Cold Weather
Salt is effective at melting ice, but only to a point. In colder temperatures, the ability of salt to work gradually falls. When the temperature drops below 20°F (-6°C), salt starts to slow down its melting action, and at temperatures of 10°F (-12°C) or lower, salt completely stops working. In such cases, cities often use calcium chloride, which works at much lower temperatures. Calcium chloride can melt ice at -25°F (-32°C). However, it’s more expensive than regular salt, so it’s often only used when temperatures drop too low for regular salt to be effective.
Conclusion
Salt is used to treat icy roads because it is an effective, affordable, and widely available way to prevent and melt ice. By lowering the freezing point of water, salt helps keep roads clear and safe during winter. While salt has some environmental drawbacks, it remains the most practical option for road treatment in most areas. If you are a business or an individual looking for road salt, we can help! At Canada Salt Group Ltd, we offer high-quality bulk road salt with multiple delivery and pickup options. Contact us for more details.
