When the ponds and lakes freeze over, you may see people ice fishing, carving a hole in the ice to get at the fish below. But have you ever tried to catch ice on a pole? This activity uses simple materials to get a “Whoa!” result. Watch the video below for the full procedure.
Here are the materials you will need:
A tray or cup
Ice
Water
Salt
String
A stick to make a fishing pole (optional)
The science behind this challenge is about changing the freezing temperature of water. Think about what we add to roads and our own driveways and sidewalks when a big snowstorm comes. Pure water freezes at 32 degrees Fahrenheit. However, water with salt added will freeze at a lower temperature. Depending on the situation, salt can be used to melt ice.
But why doesn’t the ice completely melt in our experiment? The water surrounding the ice is cold enough to help it freeze again. The salt melts enough space in the ice cubes that the string can settle in. Then water covers the string and freezes over it, making it stick to the ice cube.
Experiment with this challenge! What happens when you add lots of salt? What about just a pinch? Does the wait time change the effectiveness of how many cubes stay on your string? Does the shape of the ice cube change the outcome? Change one factor at a time and record the results to find out what combination catches the most ice.
Next time you have to salt your driveway, consider how much salt you really need. How much is needed may surprise you. About 12 ounces of salt, just enough to fill a coffee cup, can treat a 20-foot-long driveway or 10 squares of sidewalk. Using more salt doesn’t make it more effective, and it could have a negative effect on the environment.
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