year 9 heat transfers

• What happens to an object's thermal energy store when it is heated?

  Energy is transferred to its thermal energy store
• What are the three ways heat can be transferred?

  Conduction, convection, and radiation
• How is heat transferred in solids?

  By conduction
• How is heat transferred in fluids?

  By convection
• How is heat transferred through empty space?

  By radiation
• What is the key idea behind conduction?

  Vibrating particles transfer energy to neighbors
• What happens when one end of a metal is heated?

  Energy is transferred to the kinetic energy store
• Why does conduction occur mainly in solids?

  Particles are held closely together
• Which materials have high thermal conductivity?

  Metals
• What is thermal conductivity?

  How well objects transfer energy by conduction
• Why are plastics used as insulators?

  They have low thermal conductivity
• What is convection?

  Heat transfer mainly in fluids
• What happens to particles in fluids when heated?

  They gain kinetic energy and move faster
• What occurs during a convection current?

  Hot particles rise, cool particles sink
• How does a blanket reduce convection?

  It stops warm air from escaping
• What do conduction and convection have in common?

  Both involve particles gaining kinetic energy
• How can heat be transferred without particles?

  Through radiation in a vacuum
• What type of waves carry energy during radiation?

  Infrared waves
• What happens to radiation emitted by hotter objects?

  They emit more radiation
• Why does it feel hot to put your hand over a barbecue?

  Your hand absorbs emitted infrared radiation
• What are the processes of heat transfer?

  • Conduction: Energy transfer through particle collisions in solids
  • Convection: Energy transfer through fluid movement
  • Radiation: Energy transfer through electromagnetic waves
• Describe the convection current process in a heated fluid.

  1. Particles near heat gain kinetic energy
  2. Less dense particles rise
  3. Cooler, denser particles sink
  4. Cycle repeats as long as heated
• What is the electromagnetic spectrum's relation to infrared radiation?

  • Infrared radiation is part of the electromagnetic spectrum
  • All objects absorb and emit infrared radiation
  • Hotter objects emit more infrared radiation
• Convection is the way heat moves through liquids and gases. Basically, when a liquid or gas gets heated, it becomes lighter and rises. As it rises, the cooler, heavier liquid or gas moves down to take its place. This creates a cycle where warm stuff goes up and cool stuff comes down, kind of like a loop. A good example is when you boil water; the hot water rises to the top while the cooler water sinks.
• Conduction is the way heat moves through solids. It happens when heat is passed from one particle to another. For example, if you put a metal spoon in a hot pot of soup, the heat from the soup warms up the spoon. The particles in the hot soup bump into the particles in the spoon, transferring heat. This is why the spoon gets hot! So, conduction is all about heat moving through direct contact.
• What is radiation?

  Process where heat energy travels in waves
• How can you feel the sun's warmth?

  Heat travels through empty space as waves
• What are the steps involved in radiation?

  1. Emission: Object emits energy as waves
  2. Travel: Waves move through space without a medium
  3. Absorption: Object absorbs waves, warming up
• What type of waves does an object like the sun emit?

  Electromagnetic waves
• What is unique about radiation compared to conduction and convection?

  Radiation doesn’t need a medium to travel
• What happens when radiation waves reach another object?

  The object absorbs the energy and warms up
• What is the main concept of radiation?

  Energy travels through waves and heats objects