Physics: Heat Transfer Flashcards
What is the difference between temperature and heat?
Temperature measures how hot or cold an object is (in °C), while heat is the total kinetic energy of particles in an object (measured in joules, J).
How does thermal energy relate to particle movement?
Heating increases particle movement, making them vibrate or move faster, which increases the total kinetic energy and thermal energy of the substance
What device measures heat energy?
A joulemeter
Why can an object with lower temperature have more thermal energy?
An object with more particles (like seawater) can have more thermal energy despite a lower temperature due to the greater number of moving particles.
How does heat energy flow?
Heat energy flows from regions of high temperature to low temperatures through convection, conduction and radiation
Define conduction
Conduction is the flow of heat energy from a region of high temperature to a region of low temperature without overall movement of the material itself
What causes conduction in metals?
Free electrons transfer energy by colliding with metal ions
Why is conduction faster in metals than non-metals?
Metals have free electrons whilst non-metals rely on slower atom to atom vibrations
How does conduction differ in metals and non metals?
Metals use free electrons, non metals use atomic vibration
Why are metals good heat conductors
They have free electrons for rapid energy transfer
Define convection
Transfer of heat through fluids (liquids and gases) from a region of high temperature to low temperatures
How does convection work in fluids
Heated fluids expands, becomes less dense, rises, then cools down and denser fluid replaces it creating a convection current
How does trapped air reduce heat loss?
Trapped air prevents heat loss by blocking out conduction and convection
