Presentation on theme: "I. ENERGY Common: Heat, light, and electricity Other forms: mechanical energy, chemical energy, and nuclear energy. These forms of energy meet the energy."— Presentation transcript:
I. ENERGY Common: Heat, light, and electricity Other forms: mechanical energy, chemical energy, and nuclear energy. These forms of energy meet the energy needs of the people on Earth.
ENERGY Energy cannot be created or destroyed Energy can, however, be changed The storage, transfer, and conversion of energy is the driving forces behind all life on Earth
A. THE NEED FOR ENERGY 1. A fuel is any substance from which energy can be obtained 2. Electricity is generated by the conversion of other forms of energy 3. This conversion is not 100 percent efficient. Some energy is converted to heat, light, or sound
THE NEED FOR ENERGY 4. Non-renewable resource – a resource that is used faster than it is replaced in nature Ex. Fossil Fuels, Sand, Metals 5. Renewable Resource – a resource that is replaced in nature faster than it is used. Ex. Oxygen, Carbon Dioxide, Water
B. Changing Energy Needs 1. Hunter-gatherer societies ○ Light, heat, and cooking ○ Wood met needs
Changing Energy Needs 2. Agricultural societies Domesticated animals ○ energy sources for plows and other farm equipment
Changing Energy Needs 3. Industrial Revolution Machines take over tasks ○ Farm equipment: horse-drawn plow gave way to tractors and harvesters Fuel consumption increases due to manufacturing and use of machines
a. Peat Found on Earth’s surface Compressed plant material High water concentration Low energy production Burns smoky Brittle and brown Low carbon concentration Resembles decaying wood
b. Lignite Compressed peat Lower water concentration Soft brown coal (40% carbon) Releases little smoke and burns quick Found below surface - Mined
c. Sub-bituminous coal Type of coal whose properties range from those of lignite to those of bituminous coal Used primarily as fuel for steam-electric power generation
d. Bituminous coal Soft black coal Most abundant in USA Forms deep below surface – Mined Less water & fewer impurities than lignite Higher carbon concentration (85%) Releases little smoke and burns hotter than lignite Widely used in industries - power plants
d. Anthracite coal Metamorphic rock Shiny black color Least water, fewest impurities Highest carbon concentration (95%) Located deeper in the ground than any of the other forms of coal Burns the hottest with the least amount of smoke Most expensive
Homework Review - Homework The use of corn to make alcohol is an example of (a) bioconversion; (b) fossil fuels; (c) hydrocarbon; (d) refining.
Homework Review - Homework Of the following the only example of a biomass fuel is (a) coal; (b) petroleum; (c) wood; (d) natural gas.
Homework Review - Homework The process by which alcohol is made by yeast is called (a) fermentation; (b) bioconversion; (c) purification; (d) distillation.
Homework Review - Homework Unlike fossil fuels, biomass fuels (a) do not release carbon dioxide; (b) are renewable resources; (c) are buried beneath the surface; (d) are not products of living things.
OTHER ORGANIC FUELS OBJECTIVES: Describe some of the problems associated with the use of fossil fuels Compare biomass fuels to fossil fuels, and give an example of a bioconversion technique
1. availability & pollution ○ The availability problem fossil fuels are not renewable All available - have already formed F. Problems associated with the use of fossil fuels
Problems with Fossil Fuels cont’ Coastal states and offshore drilling risk of environmental damage oil spills widespread habitat alteration
Problems with Fossil Fuels An alternative - depend on the oil that are already known to exist Location, Location, Location… Operation Desert Storm - supply and demand
Problems with Fossil Fuels 3. Pollution various kinds, especially air pollution a. release carbon dioxide 4. Increased use of fossil fuels since the Industrial Revolution – increased carbon dioxide in the atmosphere by more than 20% – 5. Greenhouse Effect
G. Biomass Fuels 1. A fuel formed from the products of living organisms. 2. Ex. wood, garbage, methane, and alcohol 3. Renewable Resource – Can be produced
4. Wood a. Cheap, used mostly in developing nations Cost and availability 1. Large amounts of time spent searching b. Smoke and high carbon dioxide c. Can be damaging to natural forests
5. Garbage a. Much is largely organic materials b. About two-thirds can be burned c. Heat water d. Produce steam Turn turbines Bingo… electric
6. Methane a. Swamp gas: produced in swamps from decaying plants naturally produced form of methane b. Decaying garbage in dumps also produces methane c. Methane removed from swamps and garbage dumps is used as a fuel
7. Alcohol a. Bioconversion : the conversion of organic materials into fuels Ex. Sugar cane or corn to make alcohol b. Ethanol Yeast – Fermentation i. Liquid biomass fuel Burns cleanly & Renewable
Alcohol Brazil - 2 million cars fueled by ethanol ii. Gasohol is a mixture of 90 percent gasoline to I0 percent ethanol Future: Engines that run on alcohol made from sunflower or peanut
Objective Revisited Describe some of the problems associated with the use of fossil fuels and what you think should be done to overcome these problems
Objective Revisited Compare biomass fuels to fossil fuels, and give an example of a bioconversion technique
B. Atoms and Isotopes 1. AII atoms of the same element have the same number of protons in their nuclei. a. Atomic Number - # of p+ Ex. O = 8 protons /atomic number is 8 b. Atomic Mass/ Mass # = # of protons & neutrons in the nucleus of an atom
Atoms and Isotopes c. Individuals atoms of the same element may have different mass #’s because the # of neutrons in the nucleus can vary. d. Isotope : same element but different mass number – different number of neutron.
Ions vs. Isotopes Change in Number of Electrons - No change in mass - Change in charge - Formation of an ion Change in the Number of Neutrons - Change in mass - No change in charge - Formation of an isotope
Radioactivity Alpha decay process changes one element into another 3) Half-life : the amount of time it takes for half of the atoms in a sample of a radioactive element to decay
Objective Revisited Describe the structure of the atom and the atomic nucleus. Draw an image of a planetary model of an atom and a electron cloud model. Make sure to label the three subatomic particles and give the charge and mass for each.
D. REACTIONS AND REACTORS 1. Energy holds protons and neutrons together 2. Nuclear Fission- splitting the atom; releases energy a. Can be used to Generate electricity
Nuclear Fission b. Uranium-235 most used i. Splits when struck by a neutron ii. When U-235 splits, it releases energy & forms new nuclei, called Daughter nuclei Often barium or krypton Often radioactive
E. Nuclear Reactors 1. Nuclear reactors function very similarly to fossil fuel power plants. 2. Energy is released by nuclear reaction Energy is heat Heat boils water Steam Rises Steam Turns Turbines Generates Electricty
Nuclear Reactors c. control rods regulate the speed of the chain reaction i. made of cadmium, boron, or other materials ○ absorb neutrons ○ regulate heat production coolant water may reach temperatures above 275 °C
RADIOACTIVE WASTE OBJECTIVES – Define radioactive waste, and explain the dangers that arise from it. – State the problems involved in the safe disposal of radioactive wastes.
F. RADIOACTIVE WASTE 1. Produced by Nuclear power plants ~32 metric tons typical nuclear/year ○ Reprossessed into 1.5 tons of extremely radioactive – Dangerous Large amounts of low-level waste
RADIOACTIVE WASTE Radiation is unhealthy for living things Actively dividing cells blood-cell producing bone marrow skin cells
RADIOACTIVE WASTE Radiation Exposure Large doses ○ including skin burns ○ anemia ○ death Changes in DNA ○ long-term effects ○ cancer ○ genetic mutations
RADIOACTIVE WASTE 4. Radiation exposure measured in rems Average ○ 0.2-0.5 rems / year
RADIOACTIVE WASTE Background radiation mostly comes from naturally occurring elements in our surroundings Radiation exposure varies widely, depending on where a person lives and where he or she works
G. Types of Waste 1. High-level waste Radioactive wastes that emit large amounts of radiation used uranium fuel rods control rods water used to cool and control the chain reactions a. Very Dangerous – May Also Be Poisonous b. May be radioactive for tens of thousands of yrs
Types of Waste 2. Medium-level and low-level wastes: Not as radioactive as high-level wastes larger volume of these wastes is generated Ex. mine wastes scattered around a uranium mine contaminated protective clothes of a power plant worker
Types of Waste Low-level radioactive wastes Also produced by hospitals & laboratories Less obvious damage to health than high- level wastes More common than high level wastes May pose a greater health risk to human health
H. Waste Disposal The contaminants may have long half-lives, taking thousands of years to decay Low-level wastes can be dangerous for 300 years or more
Waste Disposal 2. Long half-lives = serious disposal problem 3. Must be sealed in containers that will not corrode for thousands of years 4. U.S. government seal the wastes in glass a. must be geologically stable b. Earthquake or Volcanoes could cause spill c. Must be stored deep under the ground (costly)
Waste Disposal Almost all the high-level radioactive wastes in the world have not been disposed of permanently They sit in storage tanks outside nuclear power and weapons plants
Waste Disposal In many cases, these tanks have begun to leak, contaminating the groundwater and releasing radioactive wastes into the environment
Waste Disposal These wastes must be permanently removed before the contamination gets worse The government predicts that the cleanup of 20 of the most contaminated nuclear weapons sites in the United States could cost $600 billion
Waste Disposal Low-level wastes pose disposal problems often buried enclosed in concrete and dropped into the ocean Exposes environment to contamination Medium-level wastes have not been disposed of permanently presents many of the same problems as high-level wastes
I. Safety and Cost If the cooling and control systems in a reactor core fail, the chain reaction can no longer be controlled The core will grow hotter, causing the fuel rods and even the reactor vessel to melt Meltdown
Safety and Cost Full meltdown release huge amounts of radiation plants are built to avoid meltdowns or contain them if they occur In April I986, however, one core of the Chernobyl nuclear power plant in Ukraine did melt down
The Chernobyl plant was old and lacked many of the safety features built into newer plants The accident itself was caused by human error
The severity of this accident and the problems with radioactive waste disposal has led many people to question the wisdom of using nuclear power Nuclear power plants are also very expensive because the required safety measures are very costly
Homework Review Protons and neutrons are found together in the part of the atom called the (a) alpha particle; (b) electron; (c) nucleus; (d) isotope.
Homework Review Protons and neutrons are found together in the part of the atom called the (a) (b) (c) nucleus; (d)
Homework Review Two atoms of the same element with different mass numbers are called (a) isotopes; (b) nuclei; (c) electrons; (d) neutrons.
Homework Review Two atoms of the same element with different mass numbers are called (a) isotopes; (b) (c) (d)
Homework Review One kind of radiation not released by radioactive decay is (a) alpha particles; (b) free protons; (c) beta particles; (d) gamma rays.
Homework Review One kind of radiation not released by radioactive decay is (a) (b) free protons; (c) (d)
Homework Review All isotopes of an element contain the same number of neutrons. TRUE or FALSE
Homework Review All isotopes of an element contain the same number of neutrons. FALSE, Protons
Homework Review Beta particles contain two protons and two neutrons. TRUE or FALSE
Homework Review Beta particles contain two protons and two neutrons. FALSE, Alpha
Homework Review The fuel most commonly used in fission reactions is (a) Np-239; (b) U-238; (c) U-235; (d) Pu-239.
Homework Review The fuel most commonly used in fission reactions is (a) (b) (c) U-235; (d)
Homework Review Devices that absorb neutrons and are used to control the speed of a fission reactor are called (a) reactor vessels; (b) fuel rods; (c) containment buildings; (d) control rods.
Homework Review Devices that absorb neutrons and are used to control the speed of a fission reactor are called (a) (b) (c) (d) control rods.
Homework Review A fission chain reaction begins when an atom of U-235 is struck by a neutron. TRUE or FALSE
Homework Review A fission chain reaction begins when an atom of U-235 is struck by a neutron. TRUE
Homework Review In a fission reaction, some of the mass of the original atom is converted to energy. TRUE or FALSE
Homework Review In a fission reaction, some of the mass of the original atom is converted to energy. TRUE
Homework Review Each year, an average person in the United States is exposed to a radiation level of (a) 2 rems; (b) 0.2 rems; (c) 20 rems; (d) 200 rems.
Homework Review Each year, an average person in the United States is exposed to a radiation level of (a) (b) 0.2 rems; (c) (d)
Homework Review Pu-239 has a half-life of (a) 24 years; (b) 240 years; (c) 2400 years; (d) 24 000 years.
Homework Review Pu-239 has a half-life of (a) (b) (c) (d) 24 000 years.
Homework Review Losing control of the fission reaction in a reactor core may result in a (a) cooldown; (b) meltdown; (c) draindown; (d) cooling tower.
Homework Review Losing control of the fission reaction in a reactor core may result in a (a) (b) meltdown; (c) (d)
Homework Review The number of people forced to evacuate because of the Chernobyl accident was (a) 1,160; (b) 11,600; (c) 116,000; (d) 1,160,000.
Homework Review The number of people forced to evacuate because of the Chernobyl accident was (a) (b) (c) 116,000; (d)
Homework Review Radon gas is responsible for 25 percent of the radiation in most U.S. homes. TRUE or FALSE
Homework Review Radon gas is responsible for 25 percent of the radiation in most U.S. homes. FALSE, 55 percent
Homework Review Plutonium must be stored for 192,000 years before it is safe. TRUE or FALSE
Homework Review Plutonium must be stored for 192,000 years before it is safe. TRUE
Homework Review The cleanup of the 20 most polluted nuclear weapons facilities in the United States will cost $600 billion. TRUE or FALSE
Homework Review The cleanup of the 20 most polluted nuclear weapons facilities in the United States will cost $600 billion. TRUE
Objective Revisited Visually explain how changes in human societies have changed the demand for energy
Objective Revisited In a complete sentence describe the structure of organic fuels
Objective Revisited List the stages of coal formation and describe the characteristics of each stage.
Objective Revisited Using the map of the United States provided for you in you packet describe to areas where coal deposits are found. Generalize the type of coal found and the location. Utilize the next slide to help clarify colors
PETROLEUM AND NATURAL GAS OBJECTIVES: Describe the processes of petroleum formation and extraction. List several uses for petroleum and natural gas.
Objective Revisited In your own words or using pictures describe the processes of petroleum formation and extraction.
Objective Revisited Think back on the uses for petroleum and natural gas mentioned in this chapter so far. List which uses you personally experience in an average month.
ATOMS AND RADIOACTIVITY OBJECTIVES: – Describe the structure of the atom and the atomic nucleus. – Explain how unstable nuclei become stable by releasing radiation.
REACTIONS AND REACTORS OBJECTIVES – Discuss the fission chain reactions that power nuclear reactors – Diagram the structure and function of a nuclear reactor.
Objective Revisited Diagram the structure and function of a nuclear reactor.
OBJECTIVE REVISITED Define radioactive waste, explain the dangers that arise from it and state the problems involved in the safe disposal of radioactive wastes.
OBJECTIVE REVISITED Write a personal response to your thoughts about the Chernobyl accident.