What it shows
Waste paper, sawdust and crop leaves can be pressed into fuel blocks. Burning equal masses under adult supervision and timing a water boil shows the energy in each fuel.
The science
Biomass fuels store energy that plants captured from sunlight. Pressing dry waste into a dense block makes it burn slowly and evenly, like a small log. The heat released can be compared by measuring how much a fixed amount of water warms or how long the block burns.
Materials
Cost: free. Many items come from home or from waste; spare parts such as LEDs, motors and wire are in the store.
- Old newspaper torn into bits
- Sawdust or dry crop leaves
- A bucket of water and a cloth to squeeze
- A tin can with holes as a mould
- A kitchen scale
- A small steel pot of water and a thermometer
- A safe metal tray with three bricks to hold the pot above the fuel
- Dry wood sticks for comparison
Safety
For this project: An adult must do all burning, outdoors, in a metal tray with a bucket of water and sand nearby, while students watch from a safe distance. Never use plastic or glossy paper. Do not burn briquettes indoors, keep hair and clothes away, and cover sharp can edges with tape.
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.
Step 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.
Soak the torn paper in water for a day and squeeze it into a thick pulp.
Mix the pulp with the same mass of sawdust or dry leaf powder.
Press the mix firmly into a mould made from a tin can and push out the block.
Dry the blocks in the sun for about three days until they feel hard.
Weigh each briquette and an equal-mass piece of dry wood.
An adult burns each fuel in the tray, one at a time, under a pot of 500 ml water resting on the three bricks.
Record the burn time and the water temperature rise for each fuel.
Write the results in a table and plot a bar chart.
What you should see
Briquettes burn for a measurable time and warm the water, usually a little less than dry wood of the same mass. The table shows which mix is best.
Viva questions
A teacher or a judge will ask how it works. Try to answer each question before you open it, then compare.
01What is biomass?
Material from plants or animals used as fuel.
02Why dry the briquettes?
Water inside absorbs heat and makes them smoky.
03Why is this renewable?
New plants can be grown to replace what is burned.
04What pollutant should we reduce?
Smoke and soot from poor burning.
Take it further
Try different ratios of paper to sawdust and decide which gives the longest burn.
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
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