Middle son has spent a fair amount of time over the last few weeks making a "freezer." The idea was his alone and there have now been several versions and many, many ice cubes used. He has done all the work-I've contributed the materials only.
A large box covered in foil-the ice cubes melted fast leaving a wet floor and soggy box.
Middle son wasn't happy with this attempt and so worked on
A smaller box again covered with foil but filled with insulation aka as shredded paper and over this a layer of foil:
It will be a fair time before this design is up to keeping next week's dinner frozen but I've been really impressed by his work on this and also his interest in how "real" freezers work which has sprung from this.