Heat Transfer
What are the three types of heat transfer?
Conduction, Convection, Radiation
What happens to molecular motion when kinetic energy increases?
Molecules move faster.
Why are cooking pots made of metal but their handles are often plastic or wood?
Metal conducts heat, plastic/wood are insulators
What is the law of conservation of energy?
Energy cannot be created or destroyed, only transferred
A student says heat moves from cold objects to hot objects. Is this correct? Explain why or why not.
No, heat always moves from hot to cold objects.
Which type of heat transfer happens when you feel warmth from the sun?
Radiation
: If two objects have the same temperature, do they have the same kinetic energy? Why or why not?
No, different materials transfer heat differently.
Why do astronauts wear insulated suits in space?
To reduce heat loss from radiation, since there is no air for convection or conduction.
When ice melts in a cup of water, where does the energy come from?
Energy transfers from the water to the ice
Why do ice cubes in a drink eventually melt, even though they are colder than the liquid?
Energy from the warmer liquid transfers to the ice.
Why does metal feel colder than wood, even if both are the same temperature?
Metal is a better conductor, so it pulls heat from your hand faster.
Why does adding heat to a solid eventually make it melt?
Heat increases kinetic energy, weakening molecular bonds
How does a thermos keep your drink hot?
It reduces conduction, convection, and radiation.
Why does a metal spoon heat up when placed in hot soup?
Energy transfers through conduction.
You step out of a swimming pool on a hot day and feel cold. Why does this happen?
Water evaporating from your skin absorbs heat, cooling you.
Explain why hot air rises and cool air sinks in a room.
Convection—hot air expands, becomes less dense, and rises.
A hot metal cube is placed in room temperature water. What happens to the cube’s temperature over time?
It cools down as energy transfers to the water.)
Why does black asphalt heat up more than white concrete?
It absorbs more radiation.
hich type of heat transfer would be most affected if there was no air in the environment?
Convection, since it requires air or liquid to move heat.
A scientist heats two different materials with the same amount of energy. One heats up faster. Why?
It has a lower specific heat capacity.
A metal pot is sitting on a hot stove. Describe how all three types of heat transfer occur in this scenario
Conduction—pot touching stove, Convection—heat circulating in the liquid, Radiation—heat coming from the burner
Which material will heat up faster in the sun: metal or water? Explain why.
Metal, because it has lower specific heat capacity than water.
Why do coastal cities have milder temperatures compared to inland cities?
Water absorbs and releases heat slowly, moderating climate.
Explain how energy transfer causes weather changes.
Sun heats the Earth, creating convection currents in the atmosphere.
In what scenario could conduction, convection, and radiation all happen at the same time?
Cooking soup on a stove—conduction through the pot, convection in the liquid, radiation from the burner.