• Heat and temperature are not the same thing
• Temperature is a measure of how hot things are
• The Celsius scale of temperature is used in science
• The values of the boiling point (100oC) and freezing point of water (0oC) on the Celsius scale must be recalled and so should some typical day to day temperatures: body temperature is 37oC, room temperature is about 20oC
• There are different kinds of thermometer
• Heat is a form of energy measured in joules (J)
• Heat flows as a result of temperature differences - from hot to cold - the bigger the temperature difference the faster the heat flows
• Heat moves in three ways: conduction, convection and radiation
• Heat energy will flow more easily (more quickly) through good thermal conductors and less well (more slowly) through poor conductors
• Metals are good thermal conductors because they can use electrons to carry heat energy as well as simply passing on heat to neighbours by vibrations.
• Poor thermal conductors are called insulators
• Liquids and gases are poor thermal conductors.
• Evidence of conduction in solids, liquids and gases can be explained using the particle model
• Vibration of particles in solids, liquids and gases increases with increasing temperature and the particles move further apart because of increased vibration making the object expand on heating.
• Expansion of a material will reduce its density because the volume will increase but the mass remain the same.
• Convection - that hot fluids rise due to expansion and cooler ones sink to take their place
• that expansion of fluids causes a change (decrease) in density
• Use the particle model to explain convection in fluids
• Radiation energy (infrared) is like light energy - travels in straight lines, gets reflected and can travel through a vacuum
• Insulation can reduce unwanted energy transfer
• Use the particle model to explain changes of state
• Solids, liquids and gases can change state when energy is added or removed and these changes are reversible
• Changes of state occur at fixed temperatures (called the boiling point and melting point)
• Draw an appropriate best-fit curve/line to fit quantitative data on a graph