Heating and Cooling

• What is thermal energy?

  Total kinetic energy of particles.
• What is the difference between thermal energy and temperature?

  Thermal energy is total; temperature is average.
• What happens when heat is transferred?

  Energy moves from hot to cold objects.
• What is equilibrium in thermal energy transfer?

  Objects become the same temperature.
• What factors affect thermal energy transfer rate?

  Surface area and material type.
• What are the three ways heat is transferred?

  Conduction, convection, and radiation.
• What happens to a hot coffee on a cold day?

  It cools down as energy transfers.
• How does the temperature of coffee change when it cools down?

  The average kinetic energy of particles decreases.
• What is thermal energy transfer between hot and cold objects?

  It occurs until both reach the same temperature.
• What is equilibrium in thermal energy transfer?

  It is when objects become the same temperature.
• What happens if there is a temperature difference between objects?

  Heat will transfer from hot to cold.
• How does the temperature difference affect heat transfer speed?

  The greater the difference, the faster the transfer.
• When does heat transfer stop?

  When both objects are the same temperature.
• What factors affect the rate of thermal energy transfer?

  Surface area and material type.
• How is thermal energy transferred in conduction?

  Through particle collisions in solids.
• What are the three ways heat is transferred?

  • Conduction
  • Convection
  • Radiation
• Which materials are good thermal conductors?

  Metals are good thermal conductors.
• What are poor thermal conductors called?

  Insulators.
• Why are solid metals good conductors?

  They have free electrons that transfer energy.
• Why are gases poor conductors of heat?

  There are fewer collisions between particles.
• What happens to particles in a solid when heated?

  They vibrate faster.
• Can heat be transferred by conduction in all states of matter?

  No, only in solids.
• Which state of matter conducts thermal energy fastest?

  Solid.
• What causes convection in fluids?

  A change in density due to heating.
• What happens to hot water in a kettle?

  It rises because it is less dense.
• What is a convection current?

  Hot particles rise and cooler particles sink.
• What happens to air inside a heated balloon?

  It becomes less dense and rises.
• What occurs when a purple crystal is heated in water?

  It dissolves and colors the water purple.
• What happens to cooler water in a convection current?

  It moves in to replace the warm water.
• What is thermal energy?

  Energy that is transferred as heat.
• What are the units for measuring energy?

  Joules (J).
• What happens to temperature when heat transfer increases?

  It will rapidly increase.
• What factors affect the amount of heat energy in an object?

  Mass, temperature, and material type.
• Which material is a good conductor of heat?

  Copper.
• Why does cold air sink in a room?

  It is colder and denser than hot air.
• Which particles transfer heat energy most effectively?

  Particles moving together.
• Which substances transfer heat energy through convection?

  Liquids and gases.
• What happens to particles when a material is heated?

  They get further apart.
• What do good insulators do?

  Prevent heat from escaping or entering.
• Why is a wooden spoon better than a metal spoon for stirring hot food?

  Wooden spoons do not conduct heat well.