Explain how turbines work and list four uses of heat energy and two natural processes of scouring.

Turbines are rotated by the kinetic energy of a moving fluid. This fluid can be:

• High-pressure steam (produced by heating water using fossil fuels, nuclear reactions, or geothermal energy).
• Flowing water (from dams or tides).
• Wind (natural air currents).
• Hot combustion gases (in gas turbines).

The methods described above are used to generate electricity in:

• Thermal power plants (coal, natural gas, nuclear power plants use steam).
• Hydroelectric power plants (use flowing water).
• Wind farms (use wind).
• Geothermal power plants (use steam from the Earth's heat).

Four uses of heat energy are:

• Cooking and heating (e.g., boiling water, heating homes).
• Generating electricity (in power plants, heat produces steam to drive turbines).
• Industrial processes (e.g., melting metals, drying materials, chemical reactions).
• Sterilization (e.g., killing microorganisms in medical equipment or food).

Two natural processes of "scouring" (erosion) due to natural energy are:

• River erosion (fluvial erosion): The abrasive and hydraulic action of flowing water in rivers, driven by gravity, which scours riverbeds and banks.
• Glacial erosion: The scouring and plucking action of moving glaciers, driven by gravity, which reshapes valleys and rock surfaces.