not sure but i think styrofoam or thermocol
Closed-cell foam insulation is known to be the best at keeping water cold the longest. It has a high thermal resistance, preventing heat transfer and maintaining the temperature of the water inside for an extended period of time.
Stainless Steal
A metal bowl keeps ice cream frozen the longest.
When looking for a dog water bowl that keeps water cold, consider features like insulation, a double-wall design, or a built-in cooling mechanism. These features can help maintain the water temperature and keep it cool for your pet.
No, paper will not keep water cold for the longest time. A metal cup will keep water the same temperature for the longest time. I know this because I did a science experiment about this but instead of cold water I used hot, which won't really make a difference. The next would be glass then paper.
Ice..
It keeps the air trapped in side and has to layers with air as insulation in the middle
no !
Type your answer here... The water is too cold.
Metalic cups keeps the water cold and it can be also used to keep the water hot .
poly venal chloride
So it doesn't freeze.