Monkey's been asking me, "Why does snow melt?" So we played around with snow and ice a little to see what happens to water when you add coldness, and what happens to ice when you add warmness.
We got some ice and put it in a bowl to see what happened. Monkey played with it as it sat out, and we talked about how the room is much warmer than the freezer, so we were adding warmness to the cold ice. He was a bit surprised when we added another ice cube later, and it was much larger than the old ice cubes.
We also grabbed a bowl of snow from our deck, brought it in, and watched to see what happened. We talked again about adding warmness, because it's much warmer inside the house than it is outside. We also talked about how ice and snow are similar, only the snow is much much smaller pieces.
The last thing we did was to put some water in the ice tray where the ice cubes had been. This we put back in the freezer, and I set the timer for 15 minutes. When we checked them there was a skin of ice on the top, which Monkey put his fingers through, and discovered the water underneath. Then we put them back for another 15 minutes. This time, it was much harder to break the "skin" - I had to help him. Interestingly, not all the ice was freezing at the same rate, though I don't think that Monkey noticed that much. (The cubes further to the back of the freezer were freezing faster.) After the 3rd time we checked, we couldn't break the skin anymore.
We didn't really have any great conversation about the whole thing once we were done, but it seems to have answered Monkey's questions about why snow melts. And we had a good time doing it!