A mug of hot tea loses thermal energy by conduction, convection and radiation at the same time. Identify where each process occurs.

Explain why fibreglass loft insulation reduces the rate at which a house loses thermal energy.

What does it mean for a cooling drink to reach thermal equilibrium with its surroundings?

Trapping air between the fibres of loft insulation prevents it from circulating, which stops heat loss by ______.

True or False? In real situations, thermal energy is usually transferred by only one process (conduction, convection or radiation) at a time.

Give three everyday examples of thermal energy transfer by radiation.

Define convection.

Explain, in terms of density, why a heated fluid rises (for example above a radiator near the floor).

Explain, in terms of density, what happens when a fluid is cooled (for example by an air conditioning unit high on a wall).

How is potassium permanganate (purple dye) used to demonstrate a convection current in a beaker of water?

A convection current forms because heated fluid becomes ______ dense and rises, while cooler fluid sinks to take its place.

True or False? Convection can occur in solids.

What is wrong with the statement "heat rises" when describing convection?

What is meant by a good thermal conductor?

Define a thermal insulator.

Almost all ______ are good thermal conductors.

Give two examples of materials that are bad thermal conductors.

Why does a bare foot placed on a tile feel colder than a foot placed on a rug, even though both are at the same temperature?

A rod, half wood and half metal, is wrapped in paper and heated at the joint. Why does the paper touching the metal stay undamaged, while the paper touching the wood chars?

Ball bearings are stuck with wax to four different metal strips at equal distances from a centrally heated point. How does this apparatus allow the relative thermal conductivities of the strips to be compared?

In the experiment investigating thermal radiation from flasks of different colours, what is the independent variable and what is the dependent variable?

Give three variables that must be controlled in the experiment investigating how surface colour affects radiation of heat.

How does this experiment show that any difference in cooling rate between the flasks is due to thermal radiation, rather than conduction or convection?

In this experiment, what determines the wavelength of the thermal radiation emitted by each flask, and what determines the amount (intensity) emitted?

Give two ways of reducing error when carrying out this experiment.

Why is a heatproof mat placed under each flask in this experiment?

In this experiment, four identical flasks are painted ______, dull grey, white and silver to compare how their surface affects radiation of heat.

True or False? In this experiment, the thermometer used has a resolution of 0.1 °C.

Define thermal radiation.

Define thermal equilibrium.

What three factors affect the amount of thermal radiation emitted by a surface?

Why are black, matt surfaces good absorbers and good emitters of thermal radiation?

Why do shiny surfaces make poor absorbers and poor emitters of thermal radiation?

A body will heat up if it absorbs thermal radiation at a ______ rate than it emits it.

True or False? Thermal radiation is the only method of thermal energy transfer that can occur through a vacuum.

Define conduction.

Define free electrons.

Describe how atomic vibrations transfer thermal energy through a solid (a process that occurs in both metals and non-metals).

Why do metals conduct thermal energy faster than non-metals?

When two solids of different temperatures are in contact, thermal energy is transferred from the ______ object to the cooler object.

True or False? Conduction is the main method of thermal energy transfer in liquids and gases.