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Conduction transfers energy through interactions between particles, with mobile electrons contributing in metals. Convection involves bulk movement in fluids: warmed regions often become less dense and rise, while cooler material moves to replace them. Thermal radiation is electromagnetic and can pass through a vacuum. A vacuum reduces conduction and convection but does not stop radiation. Dark matt surfaces are generally good infrared absorbers and emitters in the standard comparison.
Video by Cognito. The video’s own board label is retained; follow the specification reference and scope notes on this lesson for assessed content.
Viewing focus: Explain conduction, convection and radiation
After watching, attempt these questions before opening the answers. You can also use the written lesson below.
After watching 1: Which transfer can cross a vacuum?
Radiation. Electromagnetic waves need no material medium.
After watching 2: What does ΔT mean in E = mcΔT?
Temperature change. Subtract the initial temperature.
What you'll be able to do
Conduction transfers energy through interactions between particles, with mobile electrons contributing in metals. Convection involves bulk movement in fluids: warmed regions often become less dense and rise, while cooler material moves to replace them. Thermal radiation is electromagnetic and can pass through a vacuum. A vacuum reduces conduction and convection but does not stop radiation. Dark matt surfaces are generally good infrared absorbers and emitters in the standard comparison.
Specific heat capacity is the energy required to raise the temperature of one kilogram by one degree Celsius or one kelvin. Use E = mcΔT with mass in kg and the temperature change, not the final temperature. A heater experiment measures electrical energy and the block’s rise, but some energy heats the surroundings or apparatus. Insulate, use good thermal contact and explain the direction of likely error. Repeats do not automatically remove systematic heat loss.
Fossil fuels and nuclear fuels are finite; wind, solar, hydroelectric and other renewable resources replenish on relevant timescales. Renewable does not mean uninterrupted or impact-free. Compare reliability, demand matching, emissions, habitat effects, cost and energy storage. Nuclear generation has low operational carbon emissions but produces radioactive waste and needs careful management. A justified recommendation uses the place, demand and evidence given, rather than a universal ranking of all resources.
Attempt these problems on paper before opening the worked reasoning. Explain your steps as well as giving a final answer.
Common mistakes to avoid
Key takeaways
Question 1: Why can a vacuum flask still lose energy?
A vacuum does not eliminate every transfer route.
Check the assessed scope and practical or mathematical requirements.
An external explanation or interactive activity to use alongside the lesson. It may include extension material.
Close the notes and answer from memory. Revisit any explanation you cannot yet reconstruct.
Test yourself
Answer a few questions, then review anything you missed.
Start with the quiz above to check the key ideas. You can also choose another topic from the practice library.