This is a link to two videos from the National Science Learning Centre – both of them linked to Christmas! The first is aimed more at primary aged children with snow and winter in mind. I’m sure you can do it even if you’re older in age (and young in mind perhaps). The video makes it look very simple, perhaps even to get an older set of students to plan it all and experiment themselves with differing amounts/types of salt and watching how fast the ice/snow melts.
I don’t think it would be too difficult to adapt to do at home with younger children either. Especially as nothing involved is hazardous or toxic (if you stick to salt). I’ve always wanted to try ice and salt based activities with normal table salt and reduced sodium salt. Add in rock salt and you have a nice little experiment.
The second video is for secondary aged students and based around experiments you can do at the Christmas table.