P1 - energy stores

Give examples of energy stores

• Kinetic energy

• Thermal energy

• Chemical energy

• Elastic potential energy

• Gravitational potential energy

• Electrostatic energy

• Magnetic energy

• Nuclear energy

What are the 3 ways energy can be transferred?

• Mechanically - when work is done

• Electrically - when moving charge does work

• Heating - When energy is transferred from a hotter object to a colder object

What does the conservation of energy state?

Energy can never be created or destroyed, just transferred from one form to another

What is power?

rate of transfer of energy - amount of work done in a given time

What is conduction?

When thermal energy transfers through a solid material

What is thermal conductivity?

Measure of how fast thermal energy transfers through a material

Why do materials used in houses have low thermal conductivity?

So heat is not lost which then reduces energy bills (and save energy resources)

How do you know if an energy transfer is efficient?

If there is less energy wasted during transfer

What are the 2 equations for efficiency?

Useful energy transfer output ÷ Total energy transfer input = efficiency

Useful power output ÷ Total power input = efficiency

How to reduce heat loss for friction?

Lubricants, such as oil can be placed between the surfaces, reducing the friction

How to reduce heat loss from a house?

• Double glazed windows - poor thermal conductor of air within the 2 panes of glass

• Thick walls - greater distance so slower rate of thermal energy transfer through wall

• Wall cavity insulation - have layers of insulation that have low thermal conductivity

• Roof insulation - made of materials that have a low thermal conductivity, as well as having a thick layer of insulation