4.8 explain how insulation is used to reduce energy transfers from buildings and the human body

NOTE: You only need to learn a few examples, I have included quite a few so you can choose and decide which ones you find easiest to remember.

Buildings

Loft insulation - a thick layer of fibreglass wool laid out across the loft floor and ceiling reduces heat loss from the house by conduction and convection

Hot water tank jacket - Fibreglass wool reduces conduction and convection

Draught-proofing - Strips of foam and plastic around doors and windows stop draughts of cold air blowing in (therefore, they reduce the amount of heat lost due to convection)

Cavity wall insulation - foam squirted into the gap between the bricks stops convection currents and radiation in the gap, the insulating foam and air trapped also help reduce heat loss by conduction

Thick curtains - Reduce heat loss by conduction and radiation

Double glazing - Two layers of glass with a small gap of air in-between them, this reduces conduction and convection

Humans

Hairs - When it's cold, the hairs on your skin stand up to trap a 'thick' layer of air all over the body (which will insulate the entire surface area). This limits the amount of heat loss by convection.

Clothes - reduce heat transfer. Pockets of air trapped between clothes reduce heat transfer by conduction (and a little convection). Also, clothes reduce the amount of heat radiated from the body (this is because the material absorbs some of the heat as it is radiated out of our bodies).

4.6 describe how energy transfer may take place by conduction, convection and radiation

Convection is the transfer of heat by the upward movement of less dense (warmer) gas/fluid and the downward movement of denser, colder gas/liquid. NOTE: convection can not occur in solids or in vacuums

Conduction is the transfer of thermal energy through a solid (the solid doesn't actually move)

Radiation is the transfer of thermal energy in infrared waves. This is also the only method of heat/thermal energy transfer that can occur in a vacuum

4.7 explain the role of convection in everyday phenomena

In everyday phenomena, convection can be useful as it will move hot air upwards. This can be useful when heating a room - hot, less dense, air by the radiator rises, its place is filled with cool, dense air, this heats, rises etc.

4.5 describe a variety of everyday and scientific devices and situations, explaining the fate pf the input energy in terms of the above relationship, including their representation by Sankey diagrams

Of course all things aim to be 100% efficient, but  thats virtually impossible. A Sankey diagram is a good way to visualise how much energy is wasted/useful (the more useful energy that goes out, the more efficient the object is). For example...

The useful energy output for a lightbulb is light energy, because thats what we want to come out. However, some of the electrical energy is transferred into heat energy. This is an example of a very inefficient lightbulb, only 10% of the energy input comes out as useful energy, the rest comes out as heat (wasted) energy.

NOTE: Inefficiency is the same for many everyday situation, e.g. a fire (for warmth) creates light; a pepper grinder creates sound (even though you just want it to move).

NOTE NOTE: In Sankey diagrams, the 'down' arrow (s) is the wasted energy, the 'straight' arrow(s) is the useful energy

4.4 know and use the relationship: efficiency = useful energy output / total energy input

Pretty self explanatory... efficiency = useful energy output / total energy input

4.3 understand that energy is conserved

Energy can never be 'lost' or 'used up', only every transferred. For example, when you turn a light on, electrical energy transfers to light energy (and a little heat energy).

4.2 describe energy transfers involving the following forms of energy: thermal (heat), light, electrical, sound, kinetic, chemical, nuclear and potential (elastic and gravitational)

This basically means what are the types of energy...

Electrical energy > whenever a current is flowing
Light energy > from the sun, light bulbs etc (when light is 'given off')
Sound energy > noise, e.g. when you should, or from a loudspeaker
Chemical energy > in foods , fuels, batteries etc
Kinetic energy > movement (everything moving has kinetic energy)
Nuclear energy > released nuclear reactions (and nothing else)
Thermal energy > this flows from hot objects to cold ones (also known as heat energy)
Gravitational Potential Energy (GPE) > anything that has the potential to fall has GPE. E.g. if you hold a tennis ball, it has GPE.
Elastic Potential Energy (EPE) > anything that can stretch has EPE. For example an electric band or a spring

NOTE: GPE, EPE and chemical energy are forms of stored energy, because the energy is not doing anything (unlike kinetic energy, for example), its just sort of there.