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The Workshop

Solar Oven

Difficulty Level: 3/5 needs some expertise

Parts and Tools

  • Empty pizza box
  • OHP film or cling film
  • Sticky tape
  • Matt black paper
  • Craft knife
  • Ruler
  • An egg
  • Small plate
  • Aluminium foil
  • PVA glue

Instructions

This Workshop shows how to construct a solar oven from an old pizza box. If placed in direct sunlight for half an hour or so, the temperature within can rise to around 135°C. Obviously it is best to pick a very hot, sunny day to conduct the test part of the practical although the construction may take place some time before.

Pizza boxes may be provided by a friendly and generous local pizza store. If this is not possible they can be constructed from sturdy cardboard.

Fig 1: Pizza box
Fig 1: Pizza box

Fig 1 shows the pizza box. Any size can be used for this as long as the box is square.

Fig 2: Square is drawn 3-4cm from the edges of the top of the box
Fig 2: Square is drawn 3-4cm from the edges of the top of the box

In fig 2, a square is drawn 3-4cm from the edges of the top of the box. Three sides of this square are cut to form a flap. Bend the flap upwards to expose the inside of the box.

Fig 3: Inside of the box and lid are covered in aluminium foil
Fig 3: Inside of the box and lid are covered in aluminium foil

In fig 3, the inside of the box and lid are covered in aluminium foil. This needs to be cut and glued in place using PVA glue. The foil is used to reflect heat into the box.

Fig 4: Black paper covering the foil on the inside of the box
Fig 4: Black paper covering the foil on the inside of the box

Fig 4 shows black paper covering the foil on the inside of the box. The black paper absorbs heat and keeps it inside the box. This helps to heat the egg.

Fig 5: Egg inside oven
Fig 5: Egg inside oven

In fig 5, the egg is broken onto a small plate and placed inside the oven.

Fig 6: OHP film or cling film glued into place
Fig 6: OHP film or cling film glued into place

Fig 6 shows the OHP film or cling film glued into place over the opening of the oven. The film acts like a greenhouse, trapping the heat inside the oven and cooking the egg. Glue the film into place, making sure there are no gaps where air can get in or out. The whole box should be as air-tight as possible.

The oven will need putting in direct sunlight for some time in order for the egg to cook completely. Alternatively for a demonstration of the oven’s abilities, place a small beaker of water inside for 30 minutes and check the temperature before and after.

Disclaimer

Before attempting any of the construction projects featured on this website, ensure you have, and know how to use, the appropriate tools, components and safety equipment and are competent to undertake the project. These guides are for information only and we hold no responsibility for any accidents, injuries or damage caused by the use or misuse of any equipment, project or information contained within this website. In short - use common sense and stay safe!