A power station turns one kind of energy into electricity in a chain of steps. To compare them, write each chain and see where they start differently and where they match.
This lesson is part of nuclear energy. The next lesson, discussing safety controls conceptually, covers how risks are managed.
How do the energy chains compare?
Write each chain from the source to electricity. The shared steps appear in the second half.
| Power source | Energy source | Heat step | What turns the turbine |
|---|---|---|---|
| Coal or gas | Chemical energy in fuel, released by burning | Burning heats water | Steam |
| Nuclear fission | Nuclear energy in uranium nuclei | Fission heats water | Steam |
| Hydroelectric | Gravitational energy of falling water | None | Moving water |
| Solar panels | Light energy | None | No turbine, direct electricity |
Coal, gas and nuclear share the same second half: steam turns a turbine, and the turbine turns a generator. The difference is the first step.
Worked example: nuclear versus coal
Question: Compare a nuclear power station and a coal power station. State one similarity and two differences.
Similarity. Both heat water into steam that turns a turbine and a generator.
Difference 1: the source of heat. Coal releases heat by burning, which is a chemical reaction. Nuclear releases heat by splitting nuclei, which is a nuclear reaction.
Difference 2: emissions and waste. Burning coal releases carbon dioxide into the air. Nuclear fission does not burn fuel, but it produces radioactive waste that must be stored safely.
A full answer is: “Coal burns to heat water, whereas nuclear fission splits uranium nuclei. Coal releases carbon dioxide, but nuclear produces radioactive waste.”
Why fuel amount matters
A small mass of nuclear fuel releases far more energy than the same mass of coal. This is because nuclear reactions release much more energy per atom than chemical reactions.
That is why a nuclear power station needs little fuel, but the fuel needs careful handling.
The mistake that costs marks
The slip is to write a one-sided answer, listing only what nuclear energy does and never comparing it. The question says “compare”, so both sides are needed.
| Wrong | Right |
|---|---|
| Nuclear is clean | Nuclear does not release carbon dioxide from fuel, whereas coal does |
| Coal is cheap | Coal burns to give heat, but it releases carbon dioxide |
| Nuclear is dangerous | Nuclear produces radioactive waste that needs long-term storage |
Watch the phrase “clean”. Avoid it unless you explain which pollutant you mean.
Check yourself
State the main energy change at the start of (a) a nuclear power station and (b) a hydroelectric station.
Answer
(a) Nuclear energy in uranium nuclei changes to heat energy during fission.
(b) Gravitational energy of the water at the top of the dam changes to kinetic energy as it falls.
What to study next
The last lesson looks at how the risks are controlled. Continue with discussing safety controls conceptually. You can also review the nuclear energy hub for the full map.
To compare power stations with a teacher, see online one-to-one Science tuition.