Physics GCSE Revision

ENERGY

topic 1

Name the 8 energy stores

Kinetic

Elastic Potential

Gravitational Potential

Chemical

Nuclear

Magnetic

Electrostatic

Thermal

Name the 4 energy transfer pathways and describe them.

Mechanical - by a force moving an object

Electrically - by an electrical current flowing

Heating - from a hotter object to colder

Radiation - by light or sound waves

What is the Conservation of Energy?

Energy cannot be created nor destroyed. Instead, it is carried along a pathway from 1 energy store to another.

Define Internal Energy

The energy stored by the particles that make up an object

What is Power?

Power is the rate of energy transfer (or work done).

Power = Work Done / Time Taken

Power is measured in Watts

Define 'Wasted Energy'.

When 1 store of energy is transferred to another, some energy is wasted (transferred into unwanted stores of energy). This dissipates (spreads out) to anything nearby.

Describe ways in which we can reduce energy loss.

Lubrication - reduces frictional forces. A moving object normally has at least 1 frictional force acting against it, causing some energy to be dissipated.

Thermal Insulation - heat will be lost in many ways. To reduce this, we: use double glazing (windows) and fit carpets (floors).

Walls in homes - we can have thicker walls

What is the aim of the RP Investigating Insulation?

To identify which material is the most effective thermal insulator.

Name the 7 apparatus needed in the Insulation RP.

2 beakers (one large, one small)

Kettle

Stopwatch

Thermometer

Measuring Cylinder

Cardboard lid with a hole for the thermometer

Various insulating material (e.g. bubble wrap and foil)

Identify the Variables in the Insulation RP.

Independent Variable - Type of insulating material

Dependent Variable - Temperature change over time

Control Variable - Volume of beakers and Type of beakers

Describe the METHOD of Insulating RP

1. Place a smaller beaker in a larger beaker.

2. Measure a fixed volume of hot water and pour it into a smaller beaker.

3. Cover the beaker with the cardboard lid and insert a thermometer through the hole so it rests in the hot water.

4. Record the starting temperature of the water.

5. Start the stopwatch every 2 minutes for a total of 20 minutes.

6. Repeat the experiment using different insulating materials in the space between the 2 beakers.

What are energy resources used for?

To generate electricity and other useful forms of energy.

Advantages and Disadvantages of fossil fuels

Advantages:

• reliable

• on-demand electricity

Disadvantages:

• NON-RENEWABLE

• Inefficient

• Contributes to global warming.

Geothermal Energy Advantages and Disadvantages

Advantages: RENEWABLE and reliable

Disadvantages: it is most efficient in areas with VOLCANIC activity close to the surface.

Wind Energy Advantages and Disadvantages.

Advantages: RENEWABLE as it comes from the wind. They don't take up much land cost. Relatively low cost.

Disadvantages: Unreliable, only produces power when wind blows. Can cause noise pollution.

Water Energy Advantages and Disadvantages (hydroelectric dams)

Advantages: RENEWABLE, more reliable than wind AND solar. Capable of producing lots of energy.

Disadvantages: Hydroelectric dams often change paths or rivers, which can force people to move houses and harm wildlife. There are fewer places to build dams.

What is the Original Source of Energy?

The sun.

• Solar power comes directly from the sun

• Fossil fuels are made up of decayed plants and animals. which originally get their energy from the sun

Define renewable and non-renewable

Renewable - IS REPLENISHED, will never run out; e.g. wind and water waves

Non-Renewable - NOT REPLENISHED, will run out; e.g. fossil fuels

What are the 2 main uses of energy resources?

Transport and Heating

Name the limits of renewable energy resources.

• Reliability - wind may not be as reliable as fossil fuels

• Cost - can be expensive; e.g. hybrid cars

• Politics - politicians may be less keen on renewable sources