Ice and Salt Experiment for Preschool

Today we have enjoyed one of our first Science Experiments that is perfect for Preschool aged Children and above! It's a fun ice and salt experiment that is low prep and low cost too! I already had all but one of the ingredients in so it only cost me a couple of pence/cents. 
We were inspired by Powerful Mothering, as soon as I saw the activity I knew I wanted to give it a try with Little N! We have done it a little differently.
You will need: Blocks of ice Food Colouring/Water colours Coarse Salt Paintbrush Bowls 
You need to begin with freezing a block or two of ice. I only did one large block today but next time I would look at having a couple of blocks done as Little N really enjoyed the activity.
To create the block of ice I used a pirex dish and left it in the freezer overnight. To remove it from the dish I held the ice in with my fingers and ran hot water over the base of the dish. As there was such a large block of ice in the dish, it did take a good couple of minutes before the ice began to budge. 
Before letting your children play with ice, always swill the ice with warm water. This starts the melting process and will prevent fingers from sticking to the ice. I would advise full adult supervision throughout anyway with salt being present.  Once the block was free, I placed it onto my Granite chopping board. It was super slippy and kept sliding around so I added a tea towel at the one end to help keep it in place. Just look how super smooth the top of the ice is.
I had several bowls that I used to add the food colouring. The food colouring worked well but you could also use watercolour paints. We may try them next time and see which we prefer. I also included an extra bowl of water to swill the colour off the paintbrush if Little N wanted to (sometimes she did, sometimes she didn't). Once everything is set up pour the course salt onto the ice. Get ready to hear the ice cracking as the salt begins to create tiny craters before your very eyes! Can you see all the little channels beginning to form? It was really interesting to watch. I must try and get a video of it next time! Take your paintbrush and begin to paint the salt. You will notice that the colour sits on the salt vibrantly before soaking down and through the craters in the ice.  As it sinks through the colours on the top of the ice begin to fade. Eventually the colours work their way completely through the ice and create colourful water trails! But why does this happen? Why does ice melt water? As we know water becomes frozen at 0 degrees Celsius. That's what we call the freezing point of water. When we add salt it lowers the freezing point which prevents ice from forming. The molecules in salt move much faster than the molecules of water which is why this reaction occurs!  That is why grit is sprinkled on the roads on frosty, snowy mornings. It helps to prevent the ice from forming, making is safer for cars and of course the people walking.
It was a great little experiment! The colours looked beautiful! I have already began freezing another block of ice in the freezer ready to do it again soon.
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