IGCSE Physics

Thermal Physics

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Main Points (EXTENDED)

Simple kinetic molecular model of matter——————————————————

States of matter

• State the distinguishing properties of solids, liquids and gases

Molecular model

• Describe qualitatively the molecular structure of solids, liquids and gases

• Interpret the temperature of a gas in terms of the motion of its molecules

• Describe qualitatively the pressure of a gas in terms of the motion of its molecules

• Describe qualitatively the effect of a change of temperature on the pressure of a gas at constant volume

• Show an understanding of the random motion of particles in a suspension as evidence for the kinetic molecular model of matter

• Describe this motion (sometimes known as Brownian motion) in terms of random molecular Bombardment

• Relate the properties of solids, liquids and gases to the forces and distances between molecules and to the motion of the molecules
• Show an appreciation that massive particles may be moved by light, fast-moving molecules

Evaporation

• Describe evaporation in terms of the escape of more-energetic molecules from the surface of a liquid

• Relate evaporation to the consequent cooling

• Demonstrate an understanding of how temperature, surface area and draught over a surface influence evaporation

Distinguish between boiling and evaporation

Pressure changes

• Relate the change in volume of a gas to change in pressure applied to the gas at constant temperature
• Recall and use the equation pV = constant at constant temperature

Thermal properties——————————————————————————

Thermal expansions of solids, liquids and gases

• Describe qualitatively the thermal expansion of solids, liquids and gases

• Identify and explain some of the everyday applications and consequences of thermal expansion

• Describe qualitatively the effect of a change of temperature on the volume of a gas at constant pressure

• Show an appreciation of the relative order of magnitude of the expansion of solids, liquids and gases

Measurement of temperature

• Appreciate how a physical property that varies with temperature may be used for the measurement of temperature, and state examples of such properties

• Recognize the need for and identify fixed points

• Describe the structure and action of liquid-in-glass Thermometers

• Describe the structure of a thermocouple and show understanding of its use for measuring high temperatures and those that vary rapidly

Thermal capacity

• Relate a rise in the temperature of a body to an increase in internal energy

• Show an understanding of the term thermal Capacity

• Describe an experiment to measure the specific heat capacity of a substance

• Use the terms latent heat of vaporization and latent heat of fusion and give a molecular interpretation of latent heat

• Describe an experiment to measure specific latent heats for steam and for ice

Melting and boiling

• Describe melting and boiling in terms of energy input without a change in temperature

• State the meaning of melting point and boiling point

• Describe condensation and solidification

Transfer of thermal energy———————————————————————-

Conduction

• Describe experiments to demonstrate the properties of good and bad conductors of heat

• Give a simple molecular account of heat transfer in solids

Convection

• Relate convection in fluids to density changes and describe experiments to illustrate convection

Radiation

• Identify infra-red radiation as part of the electromagnetic spectrum

• Describe experiments to show the properties of good and bad emitters and good and bad absorbers of infra-red radiation

Consequences of energy transfer

• Identify and explain some of the everyday applications and consequences of conduction, convection and radiation

(Cambridge IGCSE Physics ….Syllabus 2013)