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Car of the Future
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Classroom Activity
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Activity Summary
Student teams research and develop
a proposal to decrease the carbon footprint of their city's public
transportation system through the use of various new technologies and/or
alternative fuels. Students prepare a report that explains why their
transportation plan is the best one for their community.
Learning Objectives
Students will be able to:
Suggested Time
Four class periods
Multimedia Resources
Additional Materials
Background
The United States consumes 25
percent of worldwide oil production, with passenger vehicles accounting for
about 40 percent of that. Those same vehicles emit an estimated 400 metric tons
of greenhouse gases each year that pollute the air and the environment, and
that affect human health. Concerns about air pollution, carbon-dioxide
emission, and U.S. dependence on imported oil, along with record-high gasoline
prices, are driving research into non-petroleum-based fuels and technology.
Currently, some of the most promising alternatives include hydrogen fuel cells,
ethanol fuel, and electricity from batteries. In addition, car manufacturers
are investigating modifications to existing gasoline-powered cars that can
increase energy efficiency and reduce gasoline use.
A hydrogen fuel cell is a device
that turns the chemical energy in a fuel directly into electricity. The waste
product is water. A single cell consists of a sandwich of two metallic plates
with a plastic membrane between them. Hydrogen-rich fuel (derived from
gasoline, natural gas, propane, or methanol) is fed to one side of the cell,
where it combines with atmospheric oxygen to produce electricity and water.
Numerous cells are packed together into a "stack" that can generate
enough voltage to power a vehicle or some other electric device. Hydrogen fuel
cell vehicles are more efficient than conventional internal combustion engine
vehicles and produce no harmful tailpipe exhaust. However, extremely high
manufacturing costs, fuel-supply problems, fuel storage problems, limited
mileage ability, and cold-temperature sensitivity mean that a mass-market fuel
cell vehicle probably won't be available for at least 10–20
years—perhaps much longer.
Ethanol fuel is an alcohol (ethyl
alcohol) fuel that can be made from very common renewable materials, such as
sugar cane, corn, and cellulose, and is currently the most widely used
alternative to gasoline. Ethanol has long been used in motor fuel, usually as
an oxygenate additive or blended with gasoline, because ethanol emits less
harmful air pollutants than gasoline does. The standard ethanol fuel is called
E85, which is a blend of 85 percent ethanol and 15 percent gasoline. However,
ethanol contains less energy per gallon than gasoline, so E85-powered vehicles
get roughly 30 percent fewer miles per tankful than equivalent gasoline-powered
vehicles. In addition, ethanol's lower fuel economy results in more carbon
dioxide (CO2) emissions than a similar gasoline vehicle gives off.
Electricity can be used to power
electric and hybrid electric vehicles. Vehicles that run solely on electricity
produce no tailpipe emissions. (The only emissions that can be attributed to
electricity are those generated in the production process at the power plant.)
Electric vehicles operate with electricity that is stored in a battery that
must be recharged. They can be plugged into an electricity source wherever
there is a suitable outlet. One of the disadvantages of an all-electric vehicle
is that it has limited range (about 40–80 miles between charges). Hybrid
electric vehicles typically combine the internal combustion engine of a
conventional vehicle with the battery and electric motor of an electric
vehicle. The combination offers low emissions, with the power, range, and
convenient fueling of conventional (gasoline and diesel) vehicles. Unlike
electric vehicles, hybrids don't need to be plugged in. Instead, the
engine charges the battery while the vehicle is in use.
Energy-efficient technologies
include such innovations as new engine technologies, new transmission
technologies, and using new materials to create lighter vehicles, all of which
increase efficiency and reduce fuel consumption.
Before The Lesson
Bookmark the page that includes
the four NOVA Program Clips.
They focus on new technologies and alternative fuels
designed to lessen dependency on fossil fuels. A set of video focus questions
is included with each clip.
Bookmark the HTML pages with
each team's Web resources on class computers (Team
1: Hydrogen Fuel, Team 2: Ethanol Fuel,
Team 3: Vehicle Engineering,
and Team 4: Hybrid and Electric Cars).
Copy enough of the Your City's Car
of the Future handout and obtain enough posterboard so that each team will
have one handout and one piece of posterboard to work with.
The Lesson
Ask students what they think the term "going
green" means. What have students or their family members done at home,
work, or school to help sustain the planet's natural resources?
Brainstorm with students some things they could do to achieve this goal. Ask if
any of their family members currently drives an alternative-fuel-powered
vehicle. If so, how does it work?
Provide each team with the Your City's Car of the Future handout
and a piece of posterboard. Tell students they have
been hired to help the city go green by decreasing the amount of CO2
emissions from public transportation in the community. The community's
objectives are to:
- conserve natural resources
- reduce the release of CO2 into the atmosphere
- introduce a new technology or alternative fuel that is reliable, safe, and practical
Organize students into
four teams to study and work on the objectives and options. Each team will
investigate the benefits and drawbacks of a different new technology or an
alternative fuel option. After each team has presented its findings, the class
will decide as a full committee which option to choose for the city's
public transportation system.
Assign each student to one of the following teams:
- Team 1: hydrogen fuel
- Team 2: ethanol fuel
- Team 3: vehicle engineering
- Team 4: hybrid and electric cars
Direct students to watch the video clips
for their assigned topic. After each team has watched its video clip,
have team members answer their team's focus questions, listed with their video clip
(find answers in Assessment). Then address any questions students have
about their topic and allow them a sufficient amount of time to do their
research.
Ask teams research their topics using the list of Web sites you provided them, supplemented
by any resources they find on their own. Remind students to provide a list of
references for the facts they use in their presentations, including the Web
sites they use, the name of the person or organization sponsoring the Web site,
and (if available) the last time the Web site content was
Updated.
After student teams are finished preparing their
presentation, hold a mock town meeting. If possible, invite another class to
view the presentations. They can act as townspeople and can help decide which
transportation plan is best for the community. Have students debate the pros
and cons of each plan. Encourage them to consider both short-term and long-term
solutions, how each plan might be financed, and whether a combination of one or
more of the new technologies or alternative fuels might make the most sense for
the city.
Conclude the activity by voting on which plan (or
combination of plans) to adopt based on the evidence presented in the four team
proposals.
Video Clip Focus Questions
Team 1: hydrogen fuel
What type of emissions do
hydrogen fuel cells create? (Water vapor is the only emission.)
What are the dangers of using
hydrogen as a fuel? (Hydrogen is an extremely volatile element.)
What would be the challenge for
the United States if it were to convert to hydrogen-fueled vehicles? (Developing
an infrastructure for hydrogen fuel.)
Team 2: ethanol fuel
Why do critics claim it takes
more energy to make ethanol than the amount of energy you get out of it? (While
ethanol is a cleaner fuel to burn than gasoline, critics claim that fossil
fuels are used not only to produce the fertilizer and pesticides used in
cultivating the corn, but also to ferment the corn sugar needed to make the
ethanol.)
What is cellulosic biomass, and
why is it important in the quest to use ethanol as an alternative fuel? (Cellulosic
biomass is the woody structure that supports plants. It is important because it
could someday be harvested and manufactured without any burning of fossil
fuel.)
How are bacteria involved in the
production of ethanol? (One species of bacteria tears the cellulose apart to
release the sugar; another turns the sugar into ethanol.)
Team 3: vehicle engineering
How much of the energy stored in
gasoline is lost through friction? (Almost half the energy of an
engine's combustion chamber is lost to friction as pistons rub against
the walls of the cylinder.)
Does a car have to be heavy in
order to be safe? Explain. (No. Carbon-fiber composite cars can be
lightweight while still being strong.)
Why would it be difficult for
large automakers to produce cars with carbon-fiber bodies? (Carbon fiber is
expensive, and molding it into car parts is labor intensive.)
Team 4: hybrid and electric cars
How does a hybrid car work? (A
hybrid relies on both gasoline and electricity. When the car idles, it uses
electricity. At speeds where it is most efficient, the car switches to
gasoline. The batteries are being charged while the car is using gasoline.)
How can solar energy help fuel
hybrid cars? (Energy from the sun can be collected by solar cells and stored
in batteries.)
Name one drawback of all-electric
vehicles. (All-electric vehicles require a lot of batteries to go long
distances on a single charge.)
Use the following rubric to assess each team's work.
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Excellent
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Satisfactory
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Needs Improvement
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Research
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Students use resources
effectively to answer the focus questions and develop their presentation.
They include detailed descriptions of the new technology or alternative fuel,
as well the benefits and drawbacks.
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Students need assistance
while viewing the clips and/or using additional resources. They are able to
develop their presentation but may provide less detailed descriptions and/or
arguments.
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Students have difficulties
viewing the clips and using the additional resources. They cannot provide
detailed descriptions of their assigned topic.
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Presentation
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Students develop a complete
and persuasive presentation that accurately presents information about their
new technology or alternative fuel. They are able to answer additional
questions about their fuel source during the presentation.
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Students create a
presentation, but it is only partly complete or not totally accurate. They
may not be able to answer additional questions about their fuel source during
the presentation.
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Students make little effort
to create an effective presentation. They cannot answer additional questions
about their new technology or alternative fuel during the presentation.
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The "Your City's Car of
the Future" activity aligns with the following National Science Education
Standards (books.nap.edu/html/nses).
Grades 5-8
Physical Science
• Properties of matter
Science and Technology
• Understandings about
science and technology
Classroom Activity Author
Jeff Lockwood taught high school astronomy, physics, and Earth science for 28 years. He has authored numerous curriculum projects and has provided instruction on curriculum development and science teaching methods for more than a decade.
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Carbon-Fiber Car of the Future
See in this Teachers' Domain video segment (5m 03s) how the use of carbon fiber to create more efficient cars can reduce weight without reducing size or durability.
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