2. Thermal physics
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2.1.1 States of matter
2.1.1.1Distinguishing properties of solids
• Know the distinguishing properties of solids, liquids and gases
2.1.1.2Terms for the changes in state between
• Know the terms for the changes in state between solids, liquids and gases (gas to solid and solid to gas transfers are not required)
2.1.2 Particle model
2.1.2.1Particle structure of solids, liquids
• Describe the particle structure of solids, liquids and gases in terms of the arrangement, separation and motion of the particles and represent these states using simple particle diagrams
2.1.2.2Relationship between the motion of
• Describe the relationship between the motion of particles and temperature, including the idea that there is a lowest possible temperature (−273 °C), known as absolute zero, where the particles have least kinetic energy
2.1.2.3Pressure and the changes in pressure
• Describe the pressure and the changes in pressure of a gas in terms of the motion of its particles and their collisions with a surface
2.1.2.4Random motion of microscopic particles
• Know: the random motion of microscopic particles in a suspension is evidence for the kinetic particle model of matter
2.1.2.5And explain this motion (sometimes
• Describe and explain this motion (sometimes known as Brownian motion) in terms of random collisions between the microscopic particles in a suspension and the particles of the gas or liquid
2.1.2.6Forces and distances between particles
• Know: the forces and distances between particles (atoms, molecules, ions and electrons) and the motion of the particles affects the properties of solids, liquids and gases
2.1.2.7Pressure and the changes in pressure
• Describe the pressure and the changes in pressure of a gas in terms of the forces exerted by particles colliding with surfaces, creating a force per unit area
2.1.2.8Microscopic particles may be moved by
• Know: microscopic particles may be moved by collisions with light fast-moving molecules and correctly use the terms atoms or molecules as distinct from microscopic particles
2.1.3 Gases and the absolute scale of temperature
2.1.3.1Qualitatively, in terms of particles
• Describe qualitatively, in terms of particles, the effect on the pressure of a fixed mass of gas of: (a) a change of temperature at constant volume (b) a change of volume at constant temperature
2.1.3.2Convert temperatures between kelvin
• Convert temperatures between kelvin and degrees Celsius; recall/use: T (in K) = θ (in °C) + 273
2.1.3.3Recall/use: pV = constant for a fixed
• Recall/use: pV = constant for a fixed mass of gas at constant temperature, including a graphical representation of this relationship
2.2.1 Thermal expansion of solids, liquids and gases
2.2.1.1Qualitatively the thermal expansion of
• Describe qualitatively the thermal expansion of solids, liquids and gases at constant pressure
2.2.1.2Some of the everyday applications and
• Describe some of the everyday applications and consequences of thermal expansion
2.2.1.3Explain, using particle motion and
• Explain, using particle motion and arrangement, the relative order of magnitudes of the expansion of solids, liquids and gases as their temperatures rise
2.2.2 Specific heat capacity
2.2.2.1A rise in the temperature of an object
• Know: a rise in the temperature of an object increases its internal energy
2.2.2.2An increase in temperature of an
• Describe an increase in temperature of an object in terms of an increase in the average kinetic energies of all of the particles in the object
2.2.2.3Specific heat capacity as energy
• Define specific heat capacity as energy required per unit mass per unit temperature increase; recall/use: c = ΔE/(mΔT)
2.2.2.4Experiments to measure the specific
• Describe experiments to measure the specific heat capacity of a solid and a liquid
2.2.3 Melting, boiling and evaporation
2.2.3.1Melting and boiling in terms of energy
• Describe melting and boiling in terms of energy input without a change in temperature
2.2.3.2Melting and boiling temperatures for
• Know the melting and boiling temperatures for water at standard atmospheric pressure
2.2.3.3Condensation and solidification in
• Describe condensation and solidification in terms of particles
2.2.3.4Evaporation in terms of the escape of
• Describe evaporation in terms of the escape of more-energetic particles from the surface of a liquid
2.2.3.5Evaporation causes cooling of a liquid
• Know: evaporation causes cooling of a liquid
2.2.3.6Differences between boiling and
• Describe the differences between boiling and evaporation
2.2.3.7Temperature, surface area and air
• Describe how temperature, surface area and air movement over a surface affect evaporation
2.2.3.8Cooling of an object in contact with
• Explain the cooling of an object in contact with an evaporating liquid
2.3.1 Conduction
2.3.1.1Experiments to demonstrate the
• Describe experiments to demonstrate the properties of good thermal conductors and bad thermal conductors (thermal insulators)
2.3.1.2Thermal conduction in all solids in
• Describe thermal conduction in all solids in terms of atomic or molecular lattice vibrations and also in terms of the movement of free (delocalised) electrons in metallic conductors
2.3.1.3Describe, in terms of particles, why
• Describe, in terms of particles, why thermal conduction is bad in gases and most liquids
2.3.1.4There are many solids that conduct
• Know: there are many solids that conduct thermal energy better than thermal insulators but do so less well than good thermal conductors
2.3.2 Convection
2.3.2.1Convection is an important method of
• Know: convection is an important method of thermal energy transfer in liquids and gases
2.3.2.2Convection in liquids and gases in
• Explain convection in liquids and gases in terms of density changes and describe experiments to illustrate convection
2.3.3 Radiation
2.3.3.1Thermal radiation is infrared
• Know: thermal radiation is infrared radiation and that all objects emit this radiation
2.3.3.2Thermal energy transfer by thermal
• Know: thermal energy transfer by thermal radiation does not require a medium
2.3.3.3Effect of surface colour (black or
• Describe the effect of surface colour (black or white) and texture (dull or shiny) on the emission, absorption and reflection of infrared radiation
2.3.3.4For an object to be at a constant
• Know: for an object to be at a constant temperature it needs to transfer energy away from the object at the same rate that it receives energy
2.3.3.5What happens to an object if the rate
• Know what happens to an object if the rate at which it receives energy is less or more than the rate at which it transfers energy away from the object
2.3.3.6How the temperature of the Earth is
• Know how the temperature of the Earth is affected by factors controlling the balance between incoming radiation and radiation emitted from the Earth’s surface
2.3.3.7Experiments to distinguish between
• Describe experiments to distinguish between good and bad emitters of infrared radiation
2.3.3.8Experiments to distinguish between
• Describe experiments to distinguish between good and bad absorbers of infrared radiation
2.3.3.9Rate of emission of radiation depends
• Describe how the rate of emission of radiation depends on the surface temperature and surface area of an object
2.3.4 Consequences of thermal energy transfer
2.3.4.1Some of the basic everyday
• Explain some of the basic everyday applications and consequences of conduction, convection and radiation, including: (a) heating objects such as kitchen pans (b) heating a room by convection
2.3.4.2Applications/consequences where
• Explain applications/consequences where conduction, convection and radiation all matter, including: (a) a fire burning wood or coal (b) a car radiator