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Fuel Cells
Grade Level:
11th
Subject:
Chemistry
Teacher:
Dr. Lee-Alvarez
Prepared By:
Safa Herfat
Analyze Learners
Overview & Purpose
Education Standards Addressed
This lesson is designed to allow students to explore fuel cell
cars. Fuel cell car kits provide the students with a hands-on
experience with various lessons designed to explore the
different components of the fuel cell car. This lesson
focuses on the chemistry behind the powering the hydrogen
fuel cell car. Before working with the car kits, the first
activity requires the students to perform a laboratory
experiment with the objective of finding a favorable material,
electrolyte concentration that conducts electricity efficiently,
so hydrogen could be produced in a homemade electrolysis
apparatus thereby using fuel cell technology to generate
energy. In the second laboratory experiment, students will
implement the fuel cell car kits to investigate the power
output of their fuel cells and variations in its power output.
Science Standards:
1. Conclude that Earth has finite resources and explain that humans deplete some resources
faster than they can be renewed.
2. Predict how decisions regarding the implementation of technologies involve the weighing
of trade-offs between predicted positive and negative effects on the environment and/or
humans.
3. Compare the conductivity of different materials and explain the role of electrons in the
ability to conduct electricity.
4. Describe how ions are formed when an atom or a group of atoms acquire an unbalanced
charge by gaining or losing one or more electrons.
5. Investigate that all fuels (e.g., fossil, solar, nuclear) have advantages and disadvantages;
therefore society must consider the trade-offs among them (e.g., economic costs and
environmental impact).
6. Research sources of energy beyond traditional fuels and the advantages, disadvantages
and trade-offs society must consider when using alternative sources (e.g., biomass, solar,
hybrid engines, wind, fuel cells).
7. Describe advances and issues in physical science that have important, long-lasting effects
on science and society (e.g., atomic theory, quantum theory, Newtonian mechanics,
nuclear energy, nanotechnology, plastics and ceramics and communication technology).
Scientific Inquiry
1. Formulate testable hypotheses. Develop and explain the appropriate procedures, controls
and variables (dependent and independent) in scientific experimentation.
2. Evaluate assumptions that have been used in reaching scientific conclusions.
3. Design and carry out scientific inquiry (investigation), communicate and critique results
through peer review.
4. Explain why the methods of an investigation are based on the questions being asked.
5. Summarize data and construct a reasonable argument based on those data and other
known information.
6. Apply scientific inquiry to evaluate results of scientific investigations, observations,
theoretical models and the explanations proposed by other scientists.
Select Goals and
Teacher Guide
Student Guide
Objectives
Objectives
(Specify
skills/information that
will be learned.)
1. At the end of the 11th grade unit, students will be able to
develop fuel cells to power small vehicles.
2. At the end of the 11th grade unit, students will be able to create
an alternative fuel source using hydrogen electrolysis.
3. At the end of the 11th grade unit, students will gather and
discuss empirical results regarding electrolyte concentrations,
power output, and efficiency.
Materials Needed
 Fuel cell car kits
 Distilled water
 Voltage source
 Insulated wires
 Graduated
cylinders
STEM Objectives:
 Cincinnati needs a cheap alternative fuel source
Select
Instructional
Strategies –
This lesson includes a direct activity and an inquiry based activity
that students will have to figure out for themselves.
Information
(Give and/or
demonstrate necessary
information)
Utilize Technology
Fuel cell car kits will be purchased and assembled.
Other Resources
US Dept of Energy
http://www.eere.energy.gov
Require Learner
Participation
Catch: Show the fuel cell video from the TV show NOVA. Questions will be asked before and after.
http://www.pbs.org/wgbh/nova/teachers/viewing/3210_01_nsn.html
Informing of objectives:
Students will be informed of the objectives listed above. The main objective of this lesson is to understand hydrogen fuel cell
technology.
Prerequisite Learning:
Students should be exposed to the topics of alternative fuel sources and electrolysis.
Presenting Material:
The instructor should review electrolysis and discuss the need for an alternative fuel source and the many current events involving the
fuel crisis.
Require Learner
Participation
(Cont.)
Activity
(Describe the
independent activity to
reinforce this lesson)
Activity #1:
Objective: Find a favorable material, electrolyte concentration that conducts electricity
efficiently, so hydrogen could be produced in a homemade electrolysis apparatus
thereby using fuel cell technology to generate energy.
Hydrogen and oxygen will be produced by electrolysis of water using a basic
homemade electrolysis circuit using a variable voltage source. Electricity will be run
through water by attaching insulated wires to the voltage source and putting these
leads in the solution. Bubbles of hydrogen gas will form at the cathode and oxygen
bubbles will be formed at the anode. The gases will be collected in inverted
graduated cylinders placed over the leads. Recorded data will include time to
displace 5 mL of water and replace with hydrogen gas. The amount of displaced
water by oxygen gas will also be recorded. The type of material used for the
electrodes, the salt concentration of the solution, and the voltage will be varied to find
the optimum energy producing condition.
Note: Salt concentration should speed up gas production. Gas production will be
slowed by resistance from glass graduated cylinders that partially block current flow,
warm water that heated the electrode wires, and possible deposits that form on the
leads.
Work (in watt-hours) can also be calculated. Some fast electrolysis runs will waste
excessive amounts of energy. If you run many trials, you should be able to find a
sweet spot where the gases are formed reasonably quickly while energy needed
remains fairly low.
An efficient electrolysis system for making H and O gases has to balance speed with
lower energy requirements.
Procedure for circuit:
1) Connect the electrodes to the voltage source using the leads (w/ clips).
2) Place water in a dish. Sprinkle table salt to help carry the electrical current.
3) Place the electrodes opposite to each other in the solution. What happens
at each electrode?
4) Stir the solution, then add several drops of the indicator to the dish solution.
5) Place electrodes in the solution as before. Make observations again. Can
you explain what is happening?
Oxygen gas and acid should be formed at one electrode while H gas and a base are
formed at the other. When the acid and the base meet in the dish, they form water.
At one electrode:
2H20  4H+(acid) + O2 + 4e*electric current flows out of the solution and back to the battery
At the other electrode:
4 H20 + 4e-  2H2 + 4OH- (base)
*electrons are coming into the solution from the battery
Providing Feedback:
Prior to starting, the students will write a protocol and have it checked by the
instructor. The instructor will monitor each group’s progress and provide feedback.
Student Guide
Activity #1:
 Students will follow procedure given on
handout
 Students will record their data and findings
on a given worksheet
 Directions on how to find a mathematical
model for an exponential equation also
given on another handout.
 Answer the following questions:
1) What gas formed at the electrode
where electric current flows into the
solution?
2) What gas formed at the electric current
come off the solution and flows back to
the battery?
3) Why is one gas produced in twice the
volume as the other gas?
Student Guide
Activity #2:
You will be working with the fuel cell you will be using in your Hydrogen Sprint
vehicle and investigating the power output of your cell and variations in its power
output. Be careful not to foul your fuel cell. Remember:





use only deionized or distilled water in your fuel cell
do not exceed .5 amps input to your cell, whether from photovoltaics, battery
or electricity transformer
when connecting a power source to your fuel cell make sure you connect
positive (red) to positive and negative (black) to negative
make sure you are feeding the hydrogen and oxygen into the correct sides of
your fuel cell
hydrate the membrane of your fuel cell at least 10 minutes before using it.
Gas Collection
Attach a short piece of tubing and a clamp to each of the top gas ports (one on each
side) on your fuel cell. Attach a longer piece of tubing and a clamp to each of the
bottom gas ports (one on each side) of your fuel cell. Set up your tanks or gas
collection apparatus and fill with distilled water. Submerge the free end of each long
tube in a tank of water. Open all four clamps. Inject distilled water into the top tubes
(one at a time) until water saturates the membrane and fills up the long tubes. Close
the top clamps. Fill the gas collection part of your tank (or a test tube) with water and
invert over the tube ends in the tank of water. Attach your fuel cell to your power
supply–photovoltaic panel, transformer or battery pack–checking the polarity (positive
to positive, negative to negative). After a few seconds you should see gas pushing
through the longer tubes and into the tanks. Continue collecting gas until your tank is
full or to the amount specified by your teacher. Close the bottom tube clamps while
you set up for the next portion of the investigation.
Power Output
Attach a motor/propeller unit to the fuel cell using a set of wires with alligator clips.
Add a multimeter into the circuit in series (making a big circular circuit) and set it to
read current (amperage). Hint: Put the multimeter into the negative (returning) side of
the circuit. If it doesn’t work at first, you may have the connections backwards going
into and out of the multimeter. The second multimeter will be used to measure voltage
by touching the leads across the circuit–in parallel–between the two terminals of the
fuel cell. Set this multimeter to read voltage.
Activity #2:
Open the bottom clamps so that hydrogen and oxygen flow into the fuel cell. The
motor/propeller should begin to turn and you should have a reading on the current
multimeter. If not, check and correct your circuit. Answer questions on the lab
handout.
Providing Feedback:
Prior to starting, the students will write a protocol and have it checked by the
instructor. The instructor will monitor each group’s progress and provide feedback.
Evaluate
(Assessment)
(Steps to check for
student understanding)
The same assessment will be given at the beginning and end of the lesson. The
assessment should not take longer than 15 minutes to complete. The file name for
the assessment is Lesson 5 Assessment.doc. If students are still having trouble
grasping the concepts following the lesson, these concepts will be reviewed by the
instructor.