7th Heat Transfer

Heat moves by radiation directly through empty space from the soup to the spoon.

Heat moves by conduction as particles in the spoon collide with faster particles in the soup.

Heat moves by convection as currents form within the solid spoon carrying energy upward.

Heat moves because temperature and thermal energy are the same for all materials, so energy balances instantly.

Conduction

Convection

Radiation

Thermal equilibrium

Temperature is the total kinetic energy of all particles; thermal energy is average particle speed.

Temperature measures average particle speed and indicates hot/cold; thermal energy is the total kinetic energy of all particles.

Temperature is the heat that flows from hot to cold; thermal energy is the energy that never moves.

Temperature depends only on size; thermal energy does not depend on material.

Both have the same thermal energy because temperature is the same.

The bucket likely has more thermal energy because it contains more particles even at the same temperature.

The cup has more thermal energy because smaller objects store energy better.

Neither contains thermal energy at the same temperature.

The cup of hot tea has more thermal energy because its temperature is higher.

The bathtub has more thermal energy because it contains many more moving particles overall.

They have the same thermal energy because both are made of water.

Neither has thermal energy because energy only exists in gases.

Both beakers have the same thermal energy because they have the same temperature.

The fuller beaker has more thermal energy because it contains more total particles at 100 °C.

The half-full beaker has more thermal energy because less water heats up faster.

Neither beaker has thermal energy because temperature measures only average motion.

It stops immediately because the coffee releases heat only while being stirred.

It stops when the coffee and the surrounding air reach the same temperature, because thermal equilibrium has been reached.

It stops when the coffee cools below room temperature, because heat can only move into hotter objects.

It never stops because hot coffee always keeps transferring heat to air no matter the temperature.

Conduction—heat moves through direct contact from the hot soup to the spoon

Convection—warm liquid rises and cool liquid sinks around the spoon

Radiation—heat travels as waves through space to the spoon

Evaporation—liquid turns to gas and carries heat away from the spoon

True, because both depend only on how hot something feels.

False, because thermal energy depends on both temperature and the amount of substance.

True, because hotter objects always have more total energy than cooler ones.

False, because thermal energy is just another word for temperature.

A small metal bead at 80°C has more thermal energy than a large pan of water at 40°C.

A bathtub of warm water can have more thermal energy than a cup of hot tea.

Two identical ice cubes at the same temperature have different thermal energies.

A cup and a bathtub of water at the same temperature have equal thermal energy.