It is that time of year in Nova Scotia when winter finally begins to release us from its icy grip. Hopefully the ice covered driveways and sidewalks in the province are thawing, but if they aren’t, we have a way of giving them a final push!
Many people are familiar with this experiment: combining ice with a little salt. You will need very few materials for this one – only ice cubes (or larger pieces of ice, if you prefer), a place to melt some ice (in the sink or outside, for example), some string and salt. Both table salt and road salt work well for this; it’s great to compare them.
The experiment is very simple: ice tends to melt when it comes into contact with salt, so we’ll try that out. Sprinkling just a little salt onto an ice cube starts it getting all watery on the surface, and if you are very judicious about your quantity, you can even have a string re-freeze itself onto the ice! Road salt is chemically a bit different from table salt (don’t eat it!), so it melts ice somewhat faster.
The reason that salt causes the ice to melt is very simple: the surface of ice is constantly melting and re-freezing, at least at temperatures not too far below zero. When some of this ice turns to liquid water it dissolves a little salt, and salty water has a lower freezing temperature than fresh water. The lower the temperature of the ice, the less of it will be spontaneously melting, and the slower ice will do its job.
With the weather doing much of the melting for us these days, it’s time to think about the upcoming summer months. The Discovery Centre has the most fun and educationally-challenging Summer Science Camps for kids six to 12-years-old! If you’ve never thought about our Discovery Summer Camps, stop by our website or contact firstname.lastname@example.org to book a spot today!