Conduction, Convection and Radiation
Heat moves by contact, fluid flow and electromagnetic waves.
About this topic
Heat moves in three ways. Conduction passes energy through direct contact between vibrating particles, best in metals. Convection is the circulation of warmed fluid, which becomes less dense and rises, as in boiling water, sea breezes and heaters. Radiation is the emission of infrared electromagnetic waves, which needs no medium, as in sunlight crossing space.
In metals, free electrons carry energy rapidly, so they are good conductors, while air, wool and foam are insulators because they trap gas. Convection currents drive weather, ocean circulation and the movement of rock in Earth's mantle. All objects radiate, and hotter ones radiate far more: the power rises with the fourth power of absolute temperature.
Worked example: a thermos flask limits all three. The vacuum between its walls stops conduction and convection, and the silvered surfaces reflect radiation. A dark shirt feels hotter in the sun than a white one because it absorbs more radiation.
Uses include double glazing, loft insulation, cooking pans with metal bases and plastic handles, and solar panels. A misconception is that cold travels; actually heat leaves the warm object. Another is that heat rises; it is the hot fluid that rises, while radiation and conduction go in any direction.
Key ideas
- Conduction in solids
- Convection in fluids
- Radiation needs no medium
Quick check
Use cases: where Conduction, Convection and Radiation helps
- Homework: review the key idea behind Conduction, Convection and Radiation before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Conduction, Convection and Radiation without notes.
- Visual learning: play with the interactive lab to see how Conduction, Convection and Radiation changes when you adjust its inputs.
- Teaching a friend: explain Conduction, Convection and Radiation in your own words, then compare your version with the key ideas.
The same laws describe car crashes, sports, satellites and everyday machines.
Frequently asked questions
What is Conduction, Convection and Radiation?
Heat moves by contact, fluid flow and electromagnetic waves.
What will I learn in Conduction, Convection and Radiation?
Conduction in solids. Convection in fluids. Radiation needs no medium.
Is Conduction, Convection and Radiation part of Physics?
Yes. It is one of 150 Physics topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Conduction, Convection and Radiation lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Conduction, Convection and Radiation?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.