Candle Powered Heater - I've been looking a various ways to make these and this guy has by far the best setup. It isn't so much a how-to video. He is just showing what he used to construct his version of the terra cotta pot candle heater.
DIY:: Flower Pot Heater ~ Gives a lot of heat, costs about nothing, easy to make and it looks pretty nice, too! Clay/Terracotta pots absorb the thermal energy of the candles and convert it into radiant space heat. Reaches temperatures of 160F to 180F. Heater stays hot for hours. use caution, the inner chamber can reach 500F. Heats a small area very effectively. uses 1 to 3 candles or more. How To @: www.youtube.com/...
Fridge Without Using Electricity! Here's how it works: You take a smaller pot and put it inside a larger pot. Fill the space in between them with wet sand, and cover the top with a wet cloth. As the water evaporates from the sand, it pulls the heat out with it, cooling the inner pot.