Science (Heating and Cooling) Flashcards
Know another name for heat energy:
Thermal Energy
Know the units for measuring temperature and heat:
Temperature: Degrees Celsius (ºC)
Heat energy: Joules (J)
How can heat be transferred?
Heat can be transferred in 3 ways; conduction, convection and radiation. Conduction: solids in contact. Convection: fluids. Radiation: vacuum, solid to solid by the air.
What’s the difference between temperature and heat?
Temperature: the “hotness” (average amount of kinetic energy of particles in a substance)
Heat energy: The energy particles in a substance have
How do scientists define 0ºC and 100ºC?
0ºC= freezing point of pure water
100ºC= boiling point of pure water
Examples of heat conductors and insulators:
Conductors: Metals
Insulators: Liquids, Gases or Vacuums
Why are some materials better conductors that others?
Because they have more free electrons. The insulators have the particles further apart or not in ‘neat’ rows
Why does expansion and contraction occur?
When you add thermal energy to an object, the particles vibrate more so they separate more and this makes the object expand. Then, when the heat is removed, the particles loose energy so they vibrate less and the object contracts
Which substances can heat travel through by convection?
By fluids (liquids and gases)
How do convection currents work?
When heat is added to the particles, they vibrate more and move further apart, this makes them less dense so they rise. But when the thermal energy is removed, the particles vibrate less and get together, this makes them denser so they sink
A use of convection currents:
Shaft mining or cooling/heating your house
Which materials can and cannot infrared radiation travel through?
Infrared radiation can travel through vacuums and it can’t travel through opaque materials
What do the words emit, absorb and reflect mean?
Emit: Give out
Absorb: Take in
Reflect: To ‘throw back’ without absorbing
What kind of surfaces are good at emitting/absorbing infrared radiation?
Opaque surfaces, black/dull colours absorb really good infrared radiation but they also emit it really well
Why is it important to conserve energy?
-It costs money
-Burning fossil fuels pollutes Earth
-Fossil fuels aren’t renewable (finite)
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