Questions: Comparing Conduction, Convection, and Radiation
3 questions to test your understanding
Score: 0 / 3
Question 1 Multiple Choice
A thermos keeps drinks hot by minimizing all three heat transfer mechanisms. How does the vacuum between its walls help?
AIt blocks conduction and convection, since both require matter
BIt blocks only radiation
CIt blocks only convection
DIt increases the temperature inside
A vacuum contains no matter, so there are no particles to conduct heat or flow to create convection. Only radiation can cross a vacuum, which the thermos reduces with reflective surfaces.
Question 2 True / False
Dark-colored surfaces both absorb and emit radiation more effectively than light-colored surfaces.
TTrue
FFalse
Answer: True
This is a fundamental property: good absorbers of radiation are also good emitters. A dark pot heats up faster in the sun but also cools down faster by radiation than a shiny pot.
Question 3 Short Answer
On a cold day, why does a metal bench feel much colder than a wooden bench at the same temperature?
Think about your answer, then reveal below.
Model answer: Metal is a much better conductor of heat than wood. The metal bench conducts heat away from your body faster, making it feel colder, even though both benches are at the same temperature.
What you feel as 'cold' is actually rapid heat loss from your skin. Metal's high thermal conductivity pulls heat from your body quickly through conduction, while wood's low conductivity transfers heat slowly.