Today’s Imponderable: How Does Salt Melt Ice?

Salt is one of the first things that most homeowners stock up on before a big blizzard hits. Even though you sprinkle salt on your driveway every year before and after a big snowstorm, do you really know what it is that causes salt to melt ice?

Salt lowers the freezing point of water, which is how it melts the ice on your walkway. Even though the ice isn’t technically water in a liquid state, it does have a thin layer of water at its surface, which is what enables the salt to do its job. The salt mixes with the water and melts the ice little by little, and then it changes its composition so that it now requires the temperature to drop significantly for it to refreeze. For areas with particularly cold temperatures, there are heavy-duty salts that require temperatures as low as -20 degrees in order for the ice to freeze again.

The next time you put on your warmest layers and trek out into the cold to salt your driveway, think about the complex chemical reaction that is about to happen. It just may make the grueling process a bit more fun!

Why Does Salt Melt Ice? [About.com]
Why do they use salt to melt ice on the road in the winter? [How Stuff Works]
How Salt Melts Ice [AccuWeather]

Imponderable of the Day: Why Does Looking at the Sun Make You Sneeze?

It’s a very curious sensation: You’re inside a dark room for a bit too long and when you step back outside into the bright sunlight, you suddenly feel a sneezing fit coming on. What’s the deal?

Staring at the sun makes about 20 to 35 percent of humans sneeze, and although scientists have a general idea of what causes this sensation, it’s still a very confusing conundrum. The phenomenon, which is known as “photic sneeze reflex,” is actually a genetic trait, which is why it only affects a small percentage of people. These people have visual systems that are more sensitive than those of other people, causing them to become agitated by the sunlight and send panicked responses to all of the nerves in the face, including the somatosensory system, which controls sneezing!

Now, go ahead and impress your friends with this new tidbit of information!

Looking at the Sun Can Trigger a Sneeze [Scientific American]
Why does bright light cause some people to sneeze? [Scientific American]
Does the sun make you sneeze? It's not just you [NBC News]
How Staring at the Sun Can Make You Sneeze [Gizmodo]

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