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How to Make a Solar Water Heater With a Cardboard Box & Aluminum Can

A homemade solar water heater uses the sun̵7;s energy to heat water. One important function of such a heater is to sterilize water for drinking. It is also useful for heating water for cooking, bathing or shaving. To make a solar water heater with a cardboard box and an aluminum can, you'll need to add plastic and some form of insulation. The plastic can be a container for the can or a sheet wrapped around the box. The insulation should ideally be a reflector such as aluminum foil, but you can also use newspaper or a blanket.

Things You'll Need

Cardboard box
2-liter plastic bottle
Aluminum can
Tape
Black paint
Paintbrush
Scissors or utility knife
Water

Instructions

- 1
  Paint the sides of the aluminum can black. Make sure to leave the top unpainted and splatter-free. After the paint dries, add water to the can.
- 2
  Remove one-third of the top part of the bottle with scissors or a utility knife. Place the can inside the bottle, and then tape the top of the bottle back on.
- 3
  Select a cardboard box that is approximately 16 inches on all sides. Remove two of its adjoining sides. The remaining ones should form an L shape. Turn the aluminum foil around so that its shiny side faces you, and then tape it to the box̵7;s insides. Sit the box up so that it is vertical.
- 4
  Move the box over to a window that faces the south side, or place it in a sunny spot outside the house. Place the bottle inside it. The water inside the can will eventually become hot.

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