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Lesson Plan Three

ENERGY FOR CARS AND BUSES: WHAT WILL WE USE IN 50 YEARS?

GRADES: Nine to twelve

TIME: 120-150 minutes

PURPOSE: To help students gain an understanding of alternative energy sources for cars and school buses.

OBJECTIVE: to discover the advantages and disadvantages of types of fuel currently used to operative vehicles. To explore the changes in vehicle technology in the last 90 years. To explore the reasons why attitudes toward fossil fuel use and alternative energy sources may change over the next 50 years. To explore how changing attitudes toward fossil fuel use and alternative energy sources may affect vehicle technology in the future.

to discover the types of alternative energy sources that are currently under research, particularly for use in cars and buses.

MATERIALS:

  • poster board or construction paper (for group presentations)
  • markers or crayons
  • computers with Internet access (optional for research)

PROCEDURE:

  1. Ask students to discuss what they already know about fuel efficiency and environmental impact of those fuels in cars and/or buses. Pose the following questions:

    1. Identify the four most common fossil fuels that are currently used to operate cars, trucks and school buses in Saskatchewan.
    2. Rank these fuels from best to worst by the emissions that they contribute to the environment.
    3. Which types of cars/buses are the most fuel-efficient and why? What factors might contribute to a desire for increased fuel efficiency in cars/buses?
    4. How fuel-efficient are cars/buses today compared to 50 years ago?
    5. (Optional depending on grade level and curriculum links) What are the chemical properties of those fuels? (you may have to provide them some time to research this answer)

    See the Teacher Answer Sheet at the end of this activity.

  2. Divide the class into small groups of approximately four students each. Read the following scenario to the class:

    Pretend that you live in the year 3000. Your group is a team of archaeologists who have been studying the very interesting time period of A.D. 1910-2000. You've just excavated a site that reveals a great deal about transportation during this time period. At this site, you've found dozens of old cars and car pieces as well as school buses of numerous vintages. You've also found an old sign that says "Joe's Junkyard, Established 1975, Specializing in Antique Car Parts." Therefore, you assume the oldest cars in this junkyard are from about the year 1910, about the time cars began to be mass-produced. You know that in 2000, a catastrophic earthquake leveled this part of town and all businesses ceased to operate. You can assume that vehicles in this junkyard are models from about 1910 to 2000. Your assignment is to present a report to the country's leading archaeologists explaining the following things:

    • The ways in which attitudes toward fossil fuel use and the use of alternative energy sources changed between 1910 and 2000, and the reasons for these changes.
    • Changes to vehicle technology and fuel or energy sources between 1910 and 2000, and the ways in which these changes reflected changing attitudes toward fossil fuel use and alternative energy sources. (Depending on the context, teachers could have their students consider engine design, exhaust systems, overall weight of the vehicle, aerodynamics, etc. when considering the changes.)

    This scenario is also described on the Future Scenario Worksheet at the end this activity. It can be copied and handed out to the small groups, if desired.

  3. When students take themselves out of this futuristic scenario and into the present time, they will need to make predictions about the following things:

    • Is it likely that attitudes toward fossil fuel use will change over the next 50 years? If so, how and why?
    • What are the reasons why we might see changes in the way cars are powered? (Cost and supply of fuel, environmental impact).
    • What changes might occur in car technology in order to accommodate changing attitudes toward fuel efficiency, energy sources and environmental impact?
    • What barriers might deter technological change to improve fuel efficiency?

  4. Optional for higher grades or technically oriented classes: Ask groups to use the Internet, the library, and any other relevant resources they can find to answer the following questions:

    • How do present-day internal-combustion car engines work? How is fuel processed in the engine in order to make the car operate?
    • What can be done to increase a car's fuel efficiency?
    • What types of alternative energy sources are being developed for future cars? How do these energy sources power the car? What is the difference in environmental impact of each of the energy sources from production to end use in a vehicle? What are the advantages and disadvantages of each type of energy source? Which energy sources seem most likely to be commonly used in cars of the future?
    • What environmental, political, and cultural factors might contribute to a desire for cars with higher fuel efficiency or cars that use alternative energy sources?
    • What factors might detract from creating cars with higher fuel efficiency or cars that use alternative energy sources?

    One option might be to have one group look exclusively at school buses. Some interesting comparisons could be made to the automobile industry. The group could collect specific information showing emission reductions and financial savings realized by a school division that has changed their bus fleet to natural gas fuel rather than gasoline. The class could then discuss what would happen if all the cars in a city changed to natural gas.

  5. Once they've finished their research, have groups prepare their reports. The reports should have two components:

    • Oral presentation: Have groups make oral presentations to a panel of archaeologists (i.e., the rest of the class) describing the things that their team has found in Joe's Junkyard and the conclusions it has reached concerning the questions they investigated in steps 1 to 3 (and 4 if applicable) of this lesson. Students should include visual aids when appropriate.
    • Written paper: Have each student individually write a two- to three-page paper describing the conclusions his or her group has drawn from Joe's Junkyard and summarizing the group's predictions for the ways in which energy sources and attitudes toward energy sources will change over the next 50 years (2000-2050).

    Note: It's entirely possible that students will conclude that the public is not likely to change its attitudes toward fossil fuel use, that car companies will not follow through with plans to create cars powered by alternative energy sources, and that things won't be all that different 50 years from now. It's fine for them to draw this conclusion, but they must support their argument with evidence from their research.

TEACHER ANSWER SHEET

ENERGY FOR CARS AND BUSES: WHAT WILL WE USE IN 50 YEARS?

  1. Identify the four most common fossil fuels that are currently used to operate cars, trucks and school buses in Saskatchewan

    The four most common fossil fuel used to operate care are gasoline, diesel fuel, natural gas and propane.

    Other predictable answers include:

    • Electric

      An electric car has a battery and a charger for replenishing the battery's power from an electrical outlet. The motor of an electric car harnesses the battery's electrical energy by converting it to kinetic energy, or energy that makes the car move.

      Electric cars are a cleaner way to convert fossil fuels to automotive power. The fossil fuels are burned at a power plant to make electricity to recharge the battery rather than in an internal-combustion engine. Substances that pollute the air can be controlled more easily at a power plant than at the tailpipes of millions of cars.

      Nevertheless, the source of the electricity has to be considered in evaluating whether or not electric cars are a good option. For example, in some jurisdictions, like California, there are systems in place that allow the cars to be charged on photovoltaic systems (solar systems that generate electricity). In contrast, in Saskatchewan, electrical cars would have to rely on our existing electrical system, 85 per cent of which is currently fossil fuel generated.

    • Alcohol or ethanol

      Fuel ethanol is not a fossil fuel, but an alcohol from the fermentation of sugar or converted starch (usually from grains or other renewable agricultural and agroforestry feedstocks). In Saskatchewan, it is commonly made from grain. It is blended with gasoline to produce a fuel that is more environmentally friendly than gasoline. In Saskatchewan, the most common blend is 15 per cent ethanol to 85 per cent gasoline, produced by Mohawk.

      The use of ethanol reduces greenhouse gases and other harmful vehicle emissions. In 2000, use of ethanol removed over 24 million kg of CO2 from the atmosphere and this number is expected to reach 100 million kg per year by 2005 as ethanol use increases.

    • Canola oil, used cooking oil, hemp oil

      These are all experimental replacements for diesel fuel.

  2. Rank these fuels from best to worst by the emissions that they contribute to the environment.

    Heavier hydrocarbon molecules have more significant emissions from combustion than lighter hydrocarbon molecules. Natural gas (methane), which is chemically the lightest fossil fuel, has the lowest emissions harmful to the environment of any fossil fuel. Next is propane, then gasoline, then diesel.

    Fossil fuel emissions include the following:

    • Carbon monoxide - a poisonous gas. Not healthy in any concentration.
    • Carbon dioxide - a "greenhouse" gas. Too much CO2 in the atmosphere is cited as one of the causes of "global warming".
    • Volatile organic compounds - when combined with CO2 and reacted by sunlight, causes a ground-level ozone commonly known as "smog". Not including Natural gas (methane) since it is the only fossil fuel that does not react to cause smog.
    • Diesel emissions also include carcinogenic (cancer causing) particulate matter, seen as soot from the tailpipe.

    Vehicle engine emissions are often confused by the media as having something to do with depletion of the upper atmospheric ozone layer. They do not. The only contribution that vehicles make to this problem comes from their air conditioners.

  3. Which types of cars/buses are the most fuel-efficient and why?

    Mile for mile, diesel engines are more fuel-efficient than spark-ignition engines (which burn either gasoline, or propane or natural gas). This is why diesel engines have been preferred for larger trucks, buses, farm machinery, and other heavy equipment. Diesel engines work best in applications where the engine is running long hours since they are the worst polluting engines when they are cold.

    To explain why diesel engines are more fuel-efficient would require a lesson in thermodynamics. Suffice to say that the higher compression ratio utilized in the diesel-cycle compression-ignition engine generates more power for the same amount of fuel.

    Thus the conundrum: Is it better for the environment to burn cleaner, or burn less? The difficult answer is to try to do both.

    What factors might contribute to a desire for increased fuel efficiency in cars/buses?

    • Reductions in emissions that contribute to global warming may become the most important factor. Next is cleaner air, but this is more important in cities, especially coastal cities that have the temperature inversions that cause emissions to accumulate close to the ground, such as Los Angeles, Vancouver and Toronto (with Lake Ontario acting like an ocean).

    • Economics (fuel costs) is another critical factor, including reliable domestic fuel supply (as opposed to foreign oil dependency) and sustainable fuel supply (depletion of non-renewable resources).

  4. How fuel-efficient are cars/buses today compared to 50 years ago?

    Many old vehicles (before 1950) used less fuel per kilometre than modern vehicles, however they were much lighter, much less crash worthy, and had little or no conveniences such as air conditioning.

    The main focus of the majority of automobiles built in the 1950's and 1960's was horsepower, not fuel economy. It has been said that a 1997 Chevrolet engine will run on the unburned gasoline coming out of the tailpipe of a 1957 Chevrolet.

    The emphasis shifted dramatically toward fuel efficiency during the "oil crisis" in the 1970's when Middle East oil shipments to the United States were interrupted. Vehicles sizes and weights were reduced, engine sizes reduced and the vehicles bodies became much more streamlined for less drag. Safety standards also increased dramatically including the introduction of air bags. Almost every component of the vehicles was made with materials that could and were being recycled.

    At the turn of the century, automakers are really just starting to produce cars that protect the environment in earnest. Innovations include: factory-built natural gas cars and trucks, electric vehicles, and hybrid vehicles that have a combination of electric motors and gasoline engines.

    There are now even the first signs of experimental hydrogen fuel-cell vehicles.

  5. What are the chemical properties of those fuels?

    • Natural gas is mainly methane, which is chemically the lightest fossil fuel. The methane molecule is CH3, one carbon atom bonded to 3 hydrogen atoms. Natural gas remains as a gas even when compressed to high pressures to be used on vehicles. It only becomes a liquid if chilled to minus 170 degrees Celsius.

    • Propane is the third lightest fossil fuel. The propane molecule is C3H8, three carbon atoms bonded to 8 hydrogen atoms. Propane is stored as a liquid at pressure of 300 psi and becomes a gas when expanded to lower pressure.

    • Gasoline is a mixture of a number of reactive hydrocarbons, often ranked by its octane rating. Octane molecules (C8H16) consist of 8 carbon atoms bonded to 18 hydrogen atoms. Gasoline is stored as a liquid at atmospheric temperatures and pressure.

    • Diesel fuel is a heavy liquid fuel, and is often referred to as diesel oil. It is ranked according to its cetane rating. Cetane molecules (C16H34) consists of 16 carbon atoms bonded to 34 hydrogen atoms. Diesel fuel is so heavy a liquid that proper additives are required to keep it flowing in extreme winter cold.

FUTURE SCENARIO WORKSHEET

ENERGY FOR CARS AND BUSES: CHANGES IN THE 21ST CENTURY

Pretend that you live in the year 3000. Your group is a team of archaeologists who have been studying the very interesting time period of A.D. 1910-2000. You've just excavated a site that reveals a great deal about transportation during this time period. At this site, you've found dozens of old cars and car pieces as well as school buses of numerous vintages. You've also found an old sign that says "Joe's Junkyard, Established 1975, Specializing in Antique Car Parts." Therefore, you assume the oldest cars in this junkyard are from about the year 1910, about the time cars began to be mass-produced. You know that in 2000, a catastrophic earthquake leveled this part of town and all businesses ceased to operate. You can assume that vehicles in this junkyard are models from about 1910 to 2000. Your assignment is to present a report to the country's leading archaeologists explaining the following things:

  • The ways in which attitudes toward fossil fuel use and the use of alternative energy sources changed between 1910 and 2000, and the reasons for these changes.

  • Changes to vehicle technology and fuel or energy sources between 1910 and 2000, and the ways in which these changes reflected changing attitudes toward fossil fuel use and alternative energy sources.