Energy

• What can thermal energy be transferred from one substance to another through?

  Conduction, convection, or radiation
• How does conduction occur?

  When particles pass on vibrations to neighboring particles
• What is convection?

  Movement of particles in a fluid transferring energy
• In what state of matter does convection occur?

  Liquids and gases
• What results from the movement of warmer particles in convection?

  Convection currents
• When does radiation occur?

  When a hot substance emits infrared radiation
• What type of wave is infrared radiation?

  Electromagnetic wave
• How can infrared radiation pass through a vacuum?

  It does not require a medium
• What are the three methods of thermal energy transfer?

  • Conduction
  • Convection
  • Radiation
• How do conduction, convection, and radiation differ in thermal energy transfer?

  • Conduction: Direct contact transfer
  • Convection: Fluid movement transfer
  • Radiation: Wave-based transfer
• What type of currents do warmer particles create in convection?

  Convection currents
• What is the primary characteristic of conduction?

  Transfer of energy through direct contact
• What is the role of infrared radiation in thermal energy transfer?

  It allows energy transfer without a medium
• What happens to particles during conduction?

  They vibrate and pass energy to neighbors
• How does convection differ from conduction in terms of particle movement?

  Convection involves fluid movement, conduction does not
• If a substance emits infrared radiation, what type of energy transfer is occurring?

  Radiation
• What is the primary medium for conduction to occur?

  Direct contact between substances
• Why can infrared radiation travel through a vacuum?

  It does not need a medium
• What is the significance of convection currents in thermal energy transfer?

  They facilitate energy distribution in fluids
• what is specific heat capacity?

  The amount of heat energy required to raise the temperature of a substance by one degrees Celsius.
• Why is lubricating the moving parts of a machine a good way of reducing energy dissipation?

  It reduces friction and therefore wasted energy
• state the law of conservation of energy

  energy cannot be created or destroyed, only stored or transferred
• What is kinetic energy?

  energy an object has from being in motion
• What is elastic potential energy?

  Energy stored in squashed, stretched and twisted materials
• What is gravitational potential energy?

  the energy stored by an object lifted up against the force of gravity
• What happens when work is done?

  Energy is transferred from one store to another
• What is power?

  The rate at which energy is transferred
• What is efficiency?

  How good a device is at transferring energy input to useful energy output
• how is energy wasted?

  • Friction between moving parts
  • Electrical resistance
  • Unwanted sound energy
• What is a conductor?

  A material that allows charge to move easily through it
• What is an insulator?

  material that does not allow charge or heat to pass through it easily
• What is thermal conductivity?

  A measure of how well a material conducts energy when heated
• What is work in physics?

  Energy transfer when a force moves an object
• How is work done calculated?

  Work done = force × distance
• What units are used to measure work done?

  Joules (J)
• What does energy transferred equal when work is done?

  Energy transferred = work done
• What is the unit of power?

  Watts (W)
• What is the relationship between power and energy transfer?

  Power is the rate of energy transfer
• What is the equation for calculating power?

  Power = work done / time
• What does one watt equal in terms of energy transfer?

  One watt equals one joule per second