One of the neat things about winter is that when it’s cold the water on lakes, ponds and in the calm stretches of creeks and rivers freezes. Standing next to a frozen lake or pond, you can sometimes hear weird sounds like whale talk – that’s the ice contracting and expanding.
When a lake is frozen, you can actually walk out on top of it. How wild is that? Of course, to be safe, you should never go out on the ice unless you’re accompanied by an adult who has checked the ice’s thickness. Falling through thin ice is very dangerous. So be safe.
Being the curious individual you are, you may wonder why oceans don’t freeze except in the very far north and south – really, really cold places like the arctic and Antarctica. And if you’ve ever seen your parents sprinkle salt on their icy sidewalk or driveway to melt the ice, you may be wondering how that works.
It’s the salt in ocean water that, like your sidewalk, keeps the water from freezing – to a point. You see, salty water has a lower freezing temperature. In other words, it has to be colder to freeze saltwater.
Regular water freezes at 32 degrees. Water that’s nearly saturated with salt will freeze at about minus 6 degrees.
You can experiment by putting some regular water and some salty water in separate containers. Place them in your freezer. Check them in about 15 minutes and see if the regular water is starting to freeze and the salty water is not.
— Brett French, Gazette Outdoors editor