How to use - Solar oven in a jar

Half-fill the small jar with chocolate chunks and small pieces of banana.

Screw the double lid on the small jar.

Screw the large jar on the double lid.

Squeeze the jar in the expanded polystyrene box.

On a full sunny day, place the oven straight in front of the Sun.

Wait at least 1 hour to finally enjoy a hot chocolate banana treat.

This proposal can be improved in many ways.

Here are a few questions you could try to answer :

• What maximum temperature can this solar oven reach?
• Why are the two jars made of glass?
• Why two jars - why not 1 or 3?
• What is the best time of the day ?
• How to precisely guide the oven to follow the movement of the Sun?
• Can you cook something else than bananas and chocolate?
• How can you ease the opening of the jars?
• Should the inner jar be only partly black?
• What is the best way to insulate ?
• How is it possible to concentrate more sun on the oven ?
• Etc...