Physics Unit 3.2: Energy Resources

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Unit 3.2: Energy Resources

1. Distinguish between renewable and non-renewable sources of energy.

Renewable sources of energy are sources of energy that can replenish itself, will not run out, and does not harm the environment. Examples are solar energy and wind energy. Non-renewable sources of energy are sources of energy that are used up once used, and cannot be replaced. Examples include coal and oil.

2. Demonstrate understanding that energy is released by nuclear fusion in the Sun.

Because of nuclear fusion reactions within the Sun, it radiates energy. A small fraction of this energy reaches the Earth.

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3. Know that the Sun is the source of energy for all our energy resources except geothermal and nuclear. 

The Sun's energy can be used for solar panels and cells. It also in the food we eat, wood that we burn, biofuels from waste, plants, and fossil fuels. The Sun's energy has helped shape the end product that we come in contact with. 

Geothermal energy is due to the heat from the deep, hot layers within the Earth. Nuclear energy comes from a process called fission, which is the process of splitting uranium atoms. The energy released form fission produces steam that can turn a turbine, similar to how the steam from heating water with fossil fuels can turn a turbine.

4. Describe how electricity or other useful forms of energy may be obtained from; 

● chemical energy stored in fuel,

● water, including the energy stored in waves, in tides, and in water behind hydroelectric dams,

● geothermal resources,

● nuclear fission,

● heat and light from the Sun (solar cells and panels)

● wind.

Chemical energy can be obtained from burning fuel. When the fuel (oil, coal, wood, waste biofuels) is burnt, it releases heat energy, resulting in an exothermic reaction.

We can also obtain energy from the movement of water. Water is moved by wind, tidal energy, or being held back in a dam and then released; the movement turns generators in the water that create energy.

As mentioned above, geothermal energy comes from hot rocks deep underground. The thermal energy released heats water, which creates steam that can drive generators or heat buildings. Nuclear energy is a reaction due to fission, and this also heats up water to create steam.

Solar cells and panels suck up heat energy directly from the Sun, as they must be in contact with the Sun in order to work.

Wind energy is using the wind's movement to push turbines and turn generators.


5. Give advantages and disadvantages of each method in terms of reliability, scale, and environmental impact.

Energy source	Advantages	Disadvantages
Fuel	- ready-made - cheap	- unenvironmentally friendly - creates greenhouse gases
Wave	- renewable - does not produce greenhouse gases	- source may not always be present
Tidal	- renewable - does not produce greenhouse gases	- source may not always be present
Hydroelectic	- renewable - does not produce greenhouse gases	- hydroelectric plants affect life in the water - expensive to develop usage sites
Geothermal	- renewable - does not produce greenhouse gases	- effectiveness varies on the location - expensive to develop usage sites
Nuclear	- a small amount of radioactive material produces lots of energy - relatively cheap - no atmosphere pollutants	- creates nuclear waste - leakage of nuclear waste is very serious
Heat	- renewable - does not produce greenhouse gases	- source may not always be present - expensive to make solar panels
Light	- renewable - does not produce greenhouse gases	- source may not always be present
Wind	- renewable - does not produce greenhouse gases	- a lot of land is needed to build wind turbines - noisy - visual pollutant - energy can't be produced in large quantities - source may not always be present

6. Recall and use the equation: efficiency = energy input/useful energy output x 100%

Efficiency = energy input/useful energy output x 100%

7. Demonstrate a qualitative understanding of efficiency. 

For example, if 100J of energy goes into a lamp and 75J of light energy comes out, the efficiency of the lamp is 75%.