 Fossil fuel: the remains of ancient organisms that changed into coal, oil, or natural gas  Most of the energy that we use comes from fossil fuels  Issues with using fossil fuels: ◦ Supply is limited ◦ Getting and using them has environmental consequences

 Four main purposes: ◦ Transportation ◦ Manufacturing ◦ Heating and cooling buildings ◦ Generating electricity to run machines and appliances

 Suitability of a fuel for each purpose depends on: ◦ Fuel’s energy content  how much power can it produce ◦ Cost ◦ Availability ◦ Safety ◦ Byproducts of a fuel’s use

 Energy in fuels is often converted into electrical energy in order to power machines  Electricity is more convenient to use ◦ Can be transported quickly across great distances  Disadvantages: ◦ Difficult to store  Can’t keep it in a storage tank ◦ Other energy sources need to be used to generate it

 Electric generator: a machine the converts mechanical energy (motion) into electrical energy ◦ Produce electrical energy by moving an electrically conductive material within a magnetic field ◦ Commercial electric generators convert the movement of a turbine into electrical energy  Turbine: a wheel that changes the force of a moving gas or liquid into energy that can do work

 Process: ◦ Burning fossil fuels release energy in the form of heat  Used to boil water and produce high-pressure steam ◦ Steam directed against blades of a turbine  makes turbine move ◦ Turbine is connected to an electric generator  turbine sets the generator in motion  generate electricity ◦ Steam from turbine directed to a condenser  cools and becomes liquid water to be cycled again

 Everything we use requires energy to produce it  People in developed countries use more energy than developing countries ◦ Developed county- a county with a lot of industrial and economic activity and where people have a steady income  Ex. United States and England ◦ Developing county- a county with little industrial and economic activity and little income  Ex. Ecuador and Kenya

 39% Electric power  28% Transportation  22% Industrial  11% Commercial and Residential

 Coal formation: ◦ Remains for plants that lived in swamps hundreds of millions of years ago ◦ Layers of sediment build on top of remains ◦ Heat and pressure from Earth’s mantle transform plants into coal

 Oil and natural gas formation: ◦ Decay of tiny marine organisms accumulate on bottom of ocean hundreds of millions of years ago ◦ Decaying organisms get buried by sediment ◦ Become heated by mantle to form complex carbon molecules ◦ Molecules break down and get trapped in porous rocks

 Asia and North America rich in coal deposits  Advantages: ◦ Inexpensive ◦ Needs little refining after it has been mined  Underground mines have little environmental effects at the surface  Surface mining can remove the top of an entire mountain

 If waste rock not properly contained  chemicals can leak out into nearby streams ◦ Ex. River in Colorado  All coals produce sulfur  joins with precipitation to produce acid rain  High quality coal= less air pollution  Low quality coal= more air pollution

 Petroleum: oil that is pumped from the ground ◦ Also know as crude oil  Make up fuels, plastics, chemicals  Accounts for 45% of world’s commercial energy use  Found in impermeable layers of rock

 Environmental effects of petroleum: ◦ Burning releases sulfur  produces smog and acid rain  Smog: fog combined with smoke and other atmospheric pollutants ◦ Burning releases carbon dioxide  contributes to global warming ◦ Oil spills