Colourful ice and some salt

I’ve gone a bit ice crazy this week, my freezer is full of all kinds of weird and wonderful creations which I’ll be showing you soon. First up is this block that I froze with straws inside, then after letting it melt for a while, removed the straws and put coloured water through so we could see the path. It worked brilliantly, so next time I’m going to try a swirly tube.

 

 

Next we poured some warm water down the straw hole to see what happened.

 

You can see here that the warm water has melted the ice and the straw hole is much bigger.

The video shows this in action.

We then tried adding salt to our ice. You can see here that the parts of the block with salt on top have melted faster than the rest.

 

What did we learn?

We learnt that warm water melts ice faster than cold water.

Why does salt melt ice?

Salt makes ice melt faster, this is because salt lowers the freezing point of water.

Other ideas to try

Can you freeze salty water? Does it then melt faster than normal water?

Could you freeze your block so you can run two colours through it and get them to mix at the end?