What it shows
A rocket stove has an insulated chimney and a small fuel feed so the fuel burns hot and clean. Comparing the boil time against a three-stone fire shows how a design change saves fuel.
The science
The tall chimney draws air in at the bottom by convection, so the fire gets plenty of oxygen and burns hotter with less smoke. Insulation of ash or sand stops heat from leaking out, and the pot sits close to the flames so more heat reaches the water. Better combustion means less fuel and less smoke for the cook.
Materials
Cost: under Rs 200. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- One large tin can and one medium can
- Sand or ash for insulation
- A metal grill or three nails for the pot rest
- Dry twigs
- A steel pot and 500 ml water
- A thermometer and stopwatch
- A metal tray and sand bucket
Safety
For this project: An adult must cut the metal and do all burning, outdoors on bare ground, with a bucket of water and sand ready. Wear closed shoes, keep children and pets away, and never use fuel indoors.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
All the safety rulesStep by step
8 steps. Do them in order, and test each part before you go on to the next. Write what you notice in a notebook as you go.
An adult cuts a square feed hole near the bottom of the large can and a matching hole in a smaller can.
Place the smaller can inside the larger one with the holes lined up and an L-shaped path joining them.
Fill the gap between the cans with sand or ash for insulation.
Set three nails or a grill on the top rim to hold the pot above the flame.
Weigh 100 g of dry twigs and light them at the feed hole.
Time how long 500 ml of water takes to boil and note the fuel used.
Repeat on a three-stone open fire with the same fuel and the same amount of water.
Compare boil time, fuel mass and smoke in a table.
What you should see
The rocket stove boils the water sooner, with less fuel and clearly less smoke than the open fire. The table of times and masses shows the saving.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
1Why is the chimney tall?
It pulls in air so the fire burns hotter.
2Why insulate it?
To keep heat inside and send it to the pot.
3What problem do cleaner stoves solve?
Smoke that harms health in kitchens.
4Why use dry wood?
Wet wood wastes heat boiling off its water and makes smoke.
Take it further
Change the feed-hole size and find the best opening for a fast, clean flame.
Change one thing, measure what happens, and add a table or chart of your readings: that is what turns a model into your own investigation.
Free ebooks for this project
Science projects
Investigatory Projects for Class 11 and 12
Topics, method and report structure for physics, chemistry and biology