- One empty, clear 67.6-ounce (2-liter) soda bottle
- One empty 24-ounce (709.8-milliliter) soda can (any can that will fit inside the bottle will work)
- A cardboard box about 16-by-16-by-16-inches (40.6-by-40.6-by-40.6-centimeters)
- Aluminum foil or empty potato chip bags with the reflective plastic inside
- Black paint
How to make it:
- Clean the soda bottle and can with dishwashing soap and water. Rinse well and let dry [source: Marlow].
- Cut the top of the soda bottle off about 1 inch (2.5 centimeters) below where it straightens at the widest point around [source: Marlow].
- Cut eight 1-inch (2.5-centimeter) slits into piece of the bottle you just cut off. Space the slits evenly around the circumference of the bottle [source: Marlow].
- Paint the outside of the aluminum can black. Make sure you don't get any paint inside the can [source: Marlow].
- Cut off the top and two sides of the cardboard box [source: Marlow].
- Glue aluminum foil or a recycled reflective surface, like the insides of potato chip bags, to the inside of the two remaining sides and bottom of the box [source: Marlow].
This is your solar heater. Here's how to use it:
- Fill the aluminum can with water [source: Marlow].
- Place the can inside the plastic bottle. Fit the slits from the top piece of the bottle around the top edge of the base of the bottle [source: Marlow].
- Put the bottle in the middle of the reflective box [source: Marlow].
- Place the box so the inside faces the sunlight. It will catch the rays and reflect them to the soda can. The black on the can will absorb the energy and heat the water inside [source: SolarCookers].