This week we are going to complete an 'ice fishing' experiment using ice and salt! You are going to need to make some 'ice fish' by freezing water into cubes overnight. You will also need to make a fishing rod (I used a wooden spoon and some ribbon but you might have a better idea!) Watch the video below to find out how to complete your experiment. There are two worksheets to complete below (either by printing, or by writing your responses onto paper). The first worksheet is to be completed before the experiment, and the second is to be completed afterwards!
We are going to find out how many 'ice fish' we can 'catch' before they melt! Let me know your high score via seesaw and I will announce a winner at the end of the week! Remember to submit any photos or videos of your experiment too, I can't wait to see! :) Have fun!
Ice Fishing Experiment.mp4
So... why does it work?
Ordinary water freezes at (32° F). When you add salt to water, it lowers the water’s freezing temperature-it has to get colder than 32° F to freeze. How much colder depends on how much salt is mixed in with the water. The salt you sprinkle on the ice cube lowers its freezing temperature and, since the ice cube can’t get any colder than it already is, it starts to melt. A little pool of water forms on top of the ice cube and the string sinks into it. As the ice cube melts, it dilutes the salt/water mixture in the little pool; the freezing point starts to go back up again. The ice refreezes, trapping the string. As soon as the ice cube hardens, you can raise it by lifting the string.