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"Coal and Petroleum" was a full chapter in the older NCERT Class 8 science book. In the 2026-27 books there is no chapter with that name, but the ideas still appear, spread across classes. This guide brings them together, shows the one calculation that turns "conserve fuel" into numbers, and lists the confusions examiners like to test.
Where are fossil fuels in the 2026-27 NCERT books?
Class 6 Curiosity, Chapter 11, "Nature's Treasures" introduces petroleum, natural gas and coal as fossil fuels, calls them non-renewable, and lists ways to conserve them.
Class 8 Curiosity, Chapter 13, "Our Home: Earth, a Unique Life Sustaining Planet" explains that burning coal and oil releases greenhouse gases such as carbon dioxide and methane, which trap heat and cause global warming.
The older Class 8 chapter "Coal and Petroleum" (2024-25 reprint) has the detail on coal products, refining and natural gas. Ask your teacher whether your school still uses it.
How do coal and petroleum form?
The older Class 8 chapter tells both stories.
Coal. About 300 million years ago, dense forests in low-lying wetlands were buried by natural processes such as flooding. Under soil, high pressure and rising temperature slowly changed the dead plants into coal. Because coal is mostly carbon, this is called carbonisation.
Petroleum and natural gas. These formed from organisms living in the sea. Their remains settled on the sea floor, were covered by sand and clay, and over millions of years, with no air and with high temperature and pressure, turned into petroleum and natural gas. Oil and gas sit above water in the rock because they are lighter than water and do not mix with it.
Neither can be made in a laboratory, the book says: the process is too slow and the conditions cannot be recreated.
What do we get from coal and petroleum?
When coal is processed, we get three products:
Coke: tough, porous, almost pure carbon; used to make steel and extract metals.
Coal tar: a thick black liquid, a mixture of about 200 substances, used to make dyes, drugs, explosives, paints and the naphthalene balls that repel moths.
Coal gas: used as a fuel in industries near coal processing plants.
Petroleum is a mixture that is separated in a refinery; this is called refining. The chapter's list of fractions and uses:
Petroleum gas, sold as LPG: fuel for homes and industry.
Petrol: motor and aviation fuel, solvent for dry cleaning.
Kerosene: stoves, lamps and jet aircraft.
Diesel: heavy vehicles and generators.
Lubricating oil: lubrication.
Paraffin wax: ointments, candles, vaseline.
Bitumen: paints and road surfacing.
Natural gas is stored under high pressure as CNG and is a cleaner fuel for vehicles. The chapter adds two dates worth knowing: the world's first oil well was drilled in Pennsylvania, USA, in 1859, and oil was struck at Makum in Assam in 1867.
How much fuel can a family save? A worked example
"Use public transport" sounds vague until you put numbers to it. Here is a made-up but realistic case.
A parent drives 12 km to work and 12 km back, five days a week. The car covers 15 km on one litre of petrol.
Distance per day = 12 + 12 = 24 km.
Petrol per day = 24 ÷ 15 = 1.6 litres.
Petrol per week = 1.6 × 5 = 8 litres.
If the parent takes the bus or metro on two of those days:
Petrol saved per week = 1.6 × 2 = 3.2 litres.
Over four weeks = 3.2 × 4 = 12.8 litres.
Two common slips: forgetting the return trip, which halves every answer, and dividing the wrong way round (15 ÷ 24 = 0.625 means nothing here). Write the units at every step: km ÷ (km per litre) = litres.
How else can we conserve fossil fuels?
The older chapter quotes the Petroleum Conservation Research Association (PCRA): drive at a constant, moderate speed; switch off the engine at traffic lights or while waiting; keep tyres at the correct pressure; and service the vehicle regularly. The Class 6 book adds walking or cycling short distances and using public transport. Burning less fuel also means less smoke and less carbon dioxide, which links this chapter to combustion and flame.
What do students get wrong?
"Fossil fuels are made from fossils of dinosaurs." The book says coal comes from buried plants and petroleum from sea organisms.
"Kerosene is not a fossil fuel." It is a fraction of petroleum, so it is. (The book uses this exact true/false item.)
"CNG is more polluting than petrol." False; the book calls CNG the less polluting fuel.
Mixing up coke and coal tar. Coke is a solid, almost pure carbon; coal tar is a liquid mixture.
Calling bitumen a coal product. The book says bitumen, a petroleum product, has replaced coal tar for surfacing roads.
A practice routine
Draw two flowcharts from memory: "dead plants to coal" and "sea organisms to petroleum and natural gas", with the conditions on each arrow.
Write the seven petroleum fractions with one use each, then check against the list.
Redo the fuel calculation for your own family's trip to school, using the distance and the vehicle's mileage.
Mix in three true/false items each day, from this chapter and the combustion chapter together.
If the formation of fossil fuels feels hard to picture, the Fermi Simulation Lab has interactive simulations for ideas that are easier to see than read.
This weekend, work out how many litres your family would save by switching one regular trip to public transport.
