Chapter 8 Vocabulary
Fossil Fuel Renewable Resource
Petroleum Photovoltaic Cell
Nonrenewable Resource Hydroelectricity
Fusion Geothermal Energy
Fission Biomass
Nuclear Reactor Population
Nuclear Waste Carrying Capacity
Pollutant Hazardous Waste
Photochemical Smog Acid Precipitation
Section 1: Fossil Fuels
Energy Resources
We use all types of energy almost every day. From furnaces and stoves to cars and phones. We are surrounded by energy.
According to the Law of Conservation of Energy, Energy cannot be created or destroyed. This means that all of the energy used is just being transformed from one form to another!
In the United States we use more energy than in any other country in the world!
22% of the energy was used in homes (heating/cooling/appliances)
28% was used for transportation
19% was used in businesses
and about 31% was used in industry and agriculture for manufacturing/food production
85% of the total energy used here came from burning fossil fuels, 8% from nuclear power plants and 7% from alternative sources.
Fossil Fuel Formation
We use fossil fuels all of the time, we use them in our cars, to make electricity, and to heat our homes.
Coal, Natural Gas, and Petroleum are all fossil fuels.
Fossil Fuels form from the remains of ancient plants and animals that were buried and altered over millions of years.
When fossil fuels are burned, a combustion reaction occurs. During this reaction carbon and hydrogen combines with oxygen to form carbon dioxide and water.
This reaction converts chemical potential energy into thermal energy and light.
The energy stored in fossil fuels is much more concentrated than other resources, like wood.
Burning coal produces 2-3x more energy than wood, and natural gas and petrolium are about 4x as much!
Lets explore some of the fossil fuels:
Petroleum
Petroleum is a flammable liquid formed from the decay of ancient organisms like plankton and algae.
It is a mixture of thousands of chemical compounds, mostly hydrocarbons(made from carbon and hydrogen)
Hydrocarbon compounds found in petroleum are different based on how the atoms are arranged. this determines the physical properties of the compounds.
The different hydrocarbons found in petroleum can be separated through Fractional Distillation.
this separation occurs in distillation towers
at oil refineries.
This is where they separate out asphalt
from gasoline and diesel fuel.
We don't just use petroleum for fuel though- it is also used to make plastics, synthetic fabrics, cosmetics and medicines.
Natural Gas
Natural gas is formed by the same processes as petroleum, but because they are a different density, the gases are found trapped on top of the petroleum deposits.
Natural gas is formed mainly from methane, but has other hydrocarbons in it as well (like propane and butane)
It contains more potential energy per kg than petroleum or coal, and burns cleaner than they do.
Coal
Coal is a solid fossil fuel found in mines.
It is formed where swamps were, the swamps were buried beneath sediment and decayed and compacted under pressure to create coal.
It was the main source of heat in homes in the US for most of the last century, now only about 1/4 of energy used in the US comes from coal.
Most of the coal burned in the US (90%) is to produce electricity.
The Cost of Fossil Fuels
Although fossil fuels are common energy resources, their uses have undesirable effects.
Burning fossil fuels:
-releases small particulates into the air that can cause breathing problems.
-releases carbon dioxide
Nonrenewable Resources
All Fossil Fuels are nonrenewable resources.
Nonrenewable Resources are resources that cannot be replaced by natural processes as quickly as they are used.
because they are nonrenewable, fossil fuel supply is running out and soon it will be very hard to get access to them.
What do you thinks this means for fuel prices? What do you think will happen because of this?
(answer on a half sheet, turn in on your way out)
Section 2: Nuclear Energy
Nuclear power plants transform nuclear energy into electrical energy
The sun is a nuclear reactor that transforms energy through the process of fusion.
Fusion occurs when atomic nuclei combine at very high temperatures. (they Fuse together)
Fusion transforms a small amount of mass into a tremendous amount of thermal energy.
it is not practical though, because the reactions happen at millions of degrees C, which uses a great deal of energy.
During Fission energy is released when the nucleus of an atom splits apart.
Fission transforms a small amount of mass into a tremendous amount of thermal energy.
These plants are practical, there are 65 plants in the US performing fission reactions, they produce 8% of the energy used in the US.
Nuclear Reactors
A Nuclear reactor uses energy from controlled nuclear reactions to generate electricity.
They contain fuel that can undergo fission and control rods that are used to control the nuclear reactions, as well as a cooling system that keeps the reactor from being damaged by the amount of heat produced
Only certain elements can be used as fuel-Uranium is one of them, among other radioactive elements.
The element is loaded into a fuel rod and undergoes a controlled chain reaction, releasing and absorbing neutrons as it goes.
The reactions occur at nuclear power plants.
These power plants are similar to fossil-fuel burning power plants, and there are benefits and risks to using nuclear power.
Benefits:
-no pollution
-no carbon dioxide
Risks:
-expensive to build
-radioactive waste
The biggest risk associated with these plants is the release of radioactive waste.
Nuclear waste is any radioactive material that results when radioactive materials are used.
The disposal of Nuclear waste has been controversial, one way is to seal waste in containers made of ceramic glass, inside a metal container buried hundreds of meters below ground.
Nuclear reactors have elaborate systems of safeguards, safety precautions and highly trained workers, but accidents still happen.
One of these accidents was the overheating of a reactor core at Chernobyl Nuclear Power Plant in the Ukraine. This caused a fire, and an explosion at the plant.
The radiation spread far and wide, killing 50, leaving 4000 with cancer, and exposing about 600,000 to the radiation.
Section 3: Renewable Energy Resource
Renewable energy resources help lessen human dependence on fossil fuels.
The demand for energy increases every day, as Earth's population increases.
As demand increases, our supply of nonrenewable resources decreases, and there are cons for many nonrenewable resources as well (disposal of nuclear energy waste)
However, there are some alternative energy resources-
A renewable resource is an energy resource that is replaced by natural processes faster than humans can consume the resource.
some renewable resources include:
Solar Energy- or energy from the sun.
-currently only 1% of the energy in the US is produced from solar energy
- there are several ways to produce Solar Energy, one is with a photovoltaic cell.
- A photovoltaic cell converts radient energy directly into electrical energy
Hydroelectricity-electric current produced from the energy of moving water
- about 9% of the energy in the US
- Collected in dams
Energy from the oceans
- Currents move turbines
Wind Energy
-Wind blows windmills
Geothermal Energy- thermal energy contained in and around magma
- water is fed through cracks in rock, is heated by the magma and returns to the surface as steam that runs a generator.
Alternative Fuels include:
-Hydrogen- fuel cells behave like a battery, hydrogen combines with oxygen to generate electrical energy, water, and heat
-Biomass - renewable organic matter, such as wood, soy, corn, sugarcane fibers, rice hulls, and animal manure.
- it is burned to convert chemical potential energy into thermal energy
Section 4: Environmental Impacts
Humans have an impact on land, water and air, which affects the natural resources available for use.
Population and Carrying Capacity
A population includes all the individuals of one species living in a particular area.
Every person alive today is dependent on Earth's natural resources. However, the Earth has a carrying capacity.
Carrying capacity is the largest number of individuals of a particular species that the environment can support, given the natural resources available.
If natural resources are consumed too quickly or the environment becomes threatened, then populations suffer.
Our impact on the environment comes from our use of resources-especially burning fossil fuels. The particulate that results from burning these fossil fuels is part of the pollution we create. Our plastics are made from petroleum, which produces pollutants when made. among other sources.
Pollutants include any substance that contaminates the environment.
There is also an impact on the land, from our extraction of fossil fuels and other resources (soil, water, wood).
Agriculture-
-uses fertilizers and herbicides that can pollute soil, water, and can endanger animals
Deforestation-
-clearing land for farms
- for urban development
- for logging
-the forested land decreases by 94,000 km2 each year
- animals losing homes
- CO2 not cleared from air as fast
Urban development-
- pavement won't let water soak into the soil--leads to flooding
Waste-
- 55% of garbage is disposed of in sanitary landfills, some is recycled or burned.
- waste can release harmful substances (lead)
- waste that is poisonous, cause cancer, or can catch fire are hazardous wastes.
Types of air pollution-
Photochemical smog is the pollution that results from the reaction between sunlight and vehicle or factory exhaust.
- cars, factories, power plants
CFCs are compounds that leak from old air conditioners and refrigerators that react with the ozone.
Acid precipitation occurs when acidic moisture falls from the sky as precipitation.
-can corrode metals & harm plants and animals
- sulfur, nitrogen, & carbon based compounds combining with air to form acids.
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