A project you can make for any science fair in Biology. This project idea is simple. All you need a mud pot big size and a mud pot medium size. You have to put the medium pot into the big pot and fill the gap with wet mud. Then it becomes a simple fridge without electricity. It does not make for meat or easily rotten food. You can use it for preserving seasonal fruits. All you have to put in the medium pot and cover them with a wet cloth. It actually works. This is a cheap and easy science project anyone can make. This does not cool fast so you have to wait.