IB Physics HL Topic 8

Simple stating of objective.

Students should understand that, in any process that involves energy transformations, the energy that is transferred to the surroundings (thermal energy) is no longer available to perform useful work.

It is expected that students will be able to construct flow diagrams for various systems including those described in sub-topics 8.3 and 8.4.

Students should know that electrical energy may be produced by rotating coils in a magnetic field.
Any force that will spin a turbine (e.g. steam from water heated by burning fossil fuels, wind, waves, etc.
Turbine causes generator to produce electricity from electromagnetic induction.

Students should be able to recognize those sources associated with CO2 emission. Students should also appreciate that, in most instances, the Sun is the prime energy source for world energy.
Different Sources:
Coal Oil Natural gas Nuclear Solar Wind Wave Tidal Hydroelectric Geothermal

1. Renewable Energy Source – source of energy that cannot be used up (eg. –hydroelectric, photovoltaic cells, active solar heaters, wind, biofuels) (NOTE: In most instances, the Sun is the primary energy source for world energy.) 2. Non-renewable Energy Source – source of energy that can be used up (eg. – coal, oil, natural gas, nuclear).

The ratio of the energy released from the fuel to the mass of the fuel consumed
Energy density is measured in J kg–1.

Greater energy density = greater energy per unit mass/volume = more energy for same mass/volume = more efficient
These factors influence choice based on energy density alone.

See image.

See image.

Students should appreciate that industrialization led to a higher rate of energy usage, leading to industry being developed near to large deposits of fossil fuels.
Industrial Revolution had large energy demands, increasing population growth
Household appliances and heavy industrial machinery require large amounts of energy, steam engine and other inventions
Geographical Fossil fuel reserves abundant in most continents Industrial developments centered around fossil fuel deposits

Students should be able to estimate the rate of fuel consumption by power stations. People demand power all the time. Used even when we sleep.

Coal Advantages -simple storage -safe Disadvantages -low energy density Oil Advantages -convenient location of rigs Disadvantages -oil spills and leaks -vulnerable to terrorist activities and natural disasters Natural gas Advantages -high energy density Disadvantages -expensive gas line setup and maintenance costs

Approximate values only.
Coal - 35Oil – 38% Natural gas – 45%

Coal Recovery -strip mining (sulfuric acid and soil erosion) -mining hazards (toxic gas and tunnel cave ins) Oil and Natural gas Recovery -extensive time to map and plan construction -expensive construction and maintenance costs -possible spill and leak risks Power Station Use -air pollution (CO₂, CO, SO₂, soot, Nitrogen oxides emissions)