Making a solar box cooker is a fun educational activity you can do with your children or grandchildren. Below are instructions I have used when on camp with local Cub Scout groups
Archimedes of Syracuse, an ancient Greek mathematician, physicist and engineer is said to have used mirrors to burn Roman ships attacking Syracuse. These mirrors would have focused the suns rays onto passing enemy ships and made them burst into flames! The mirrors that Archimedes would have used are known as parabolic reflectors and are the same shape as satellite dishes.
This idea is used today to make solar furnaces; these are huge mirrors which harness the sun’s rays to make very high temperatures. They can be used to make electricity, make hydrogen fuel or even melt steel! The largest Solar Furnace in the world is in Odeillo in the Pyrenees in France. It can generate temperatures of up to 3000C.
You can easily make your own version of a solar furnace, while you’ll be unlikely to get temperatures as high as 3000C, you will be making temperatures hot enough to cook a few hotdogs!
You will need:
A pizza box
Aluminum foil
Black card
Permanent marker
Blank OHP transparencies
Glue
Tape
Scissors
Ruler
Wooden dowel
Draw a square on the lid of the pizza box leaving a 3cm border, cut along three of the square’s sides. Form a flap by folding back along the uncut line to make a crease.
Next cover the inside of the flap with aluminum foil, make sure it is smooth with no creases and then glue it into place.
Open the box up, on the inside tape the blank OHP transparency across the hole you have just made, it will need to be securely fastened all the way round so air cannot escape through the edges. This will be your oven window.
Now line the bottom and sides of the pizza box with aluminum foil, again, glue it smooth with no creases. You now need to cover the bottom of the box with black card and tape it into place.
Close the pizza box and use the wooden dowel to prop open the flap of your oven. Adjust the tilt of the flap until the aluminum foil reflects the maximum amount of sunlight through the window into your oven.
You are now ready to do some cooking! It will need to be a sunny day for the oven to work. Try cooking some hotdogs by placing them on a piece of foil in the centre of the oven and leaving them to cook it may take 30 minutes to an hour before they are ready to eat. Get an adult to take them out of the oven and check they are completely cooked before you eat them.
You may also want to use an oven thermometer to check how hot your oven gets.
The solar oven works by using the foil-covered lid to direct the sun’s rays into the pizza box. The heat cannot escape because of the plastic window, the more rays that enter the box, the hotter it becomes meaning you get hot, tasty hotdogs!
