Smokeless chulha model
Compare fuel use and smoke between a traditional stove and a clay or tin improved stove model.
The big idea
Cooking fires fill many homes with smoke. A better stove burns the fuel more fully, so there is less smoke and less wood used.
You will need
Tick things off as you gather them.
Step by step
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Step 1: Make the open stove
Place three stones or bricks in a ring in an outdoor spot. This is the traditional style stove. It is your control.
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Step 2: Build the improved model
Use a large tin can as the outer body. Cut an opening at the bottom for fuel and one at the top for the pot. Pack clay around a small inner chamber for insulation.
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Step 3: Weigh the fuel
Weigh 100 grams of dry twigs for each stove. Use the same type of wood for both.
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Step 4: Fill the pots
Put the same amount of water, about 500 ml, in the same pot for each test, and note its starting temperature.
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Step 5: Light and time it
With an adult, light each stove in turn and time how long the water takes to boil. Watch the smoke.
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Step 6: Weigh what is left
When the water boils, remove the fuel and weigh the unburnt twigs. How much wood did each stove use?
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Step 7: Compare
Make a table of time to boil, fuel used and how smoky each stove was. Which was better, and by how much?
What to look for
- The improved stove produces much less smoke.
- It boils water using less wood.
- The insulated chamber stays hotter.
Why it works
Smoke is unburnt fuel. An open fire loses a lot of heat to the air and does not burn the wood fully, so smoke pours out. An enclosed, insulated chamber keeps the fire hotter and draws in more air, so the wood burns more completely. That gives more heat from the same wood and far less harmful smoke, which protects the lungs of the people who cook.
Try this next
- Add a chimney and compare again.
- Try different fuels, such as dry sticks and dung cakes.
- Interview someone at home about how they cook.
Stay safe
Do this outdoors, with an adult, away from anything that can burn. Keep a bucket of water ready. The stove and pot get very hot. Tie back hair and loose clothing.
Link to the grid
Cooking fuel is energy too. Moving homes from wood to cleaner fuels or electric cooking can improve health, and it adds to the grid's load.
Learn how the grid works