Water is H2O

    Water is H2O
    Transfer of Energy
    Electrolysis
    Series vs. parallel power
    Building a fuel cell car
    Building a hydrogen        highway

    Characteristics curve of       fuel cells
    Avagadro's rule
    Transfer of energy
    Siting wind, solar,       hydrogen systems

    Evaluating the power of        fuel cells
    Hydrogen production
    Fuel Cells as part of an        electric car system

    Characteristics curve of
       fuel cells
    Avagadro's Rule

 

Stopwatch

A complete fuel cell kit that includes:

   A hydrogen/oxygen fuel cell. Some fuel cell kits include fuel cells that do not use direct oxygen,    but air.

   Power supply (battery pack, solar panel or electric power supply). It is important to have the    correct voltage going into the fuel cell. Too much voltage will destroy the fuel cell.

   Hydrogen and oxygen gas storage - usually in cylinders, but some kits might include syringes for    storage. Do not choose a kit that uses balloons for storage as students will not be able to measure    the amount of gas stored.

There are a number of fuel cell kits you can use for this experiment.

Tutorial RFC Set | $250.00 This is our recommendation kit for this lesson plan. The kit includes very robust components. The components can be used in a wide variety of experiments. To prevent spilling, each component has a magnetic bottom and a metal experiment tray is included. The experiment manual is really more for high school or technical school level, but can be adapted for lower grades.

Dr. Fuel Cell Model Car Demo | $250.00 This kit is very robust. The wiring is strong and the chassis of the car provides a strong base for students. It is perfect for this experiment. Students can easily see the hydrogen and oxygen in the storage cylinders. The biggest drawback to this kit is that it does not allow for much flexibility because the storage cylinders are attached to the fuel cell. If you want a fuel cell kit that is robust, will allow for electrolysis and will make a car go, this is a good kit. This kit includes a solar panel and an experiment manual.

Fuel Cell Car Science Kit | $72.00 This is an inexpensive kit that allows students to perform a variety of experiments. It is the best kit for the value. One problem with this kit is that the storage can be easily spilled and students need to be especially careful about this. If water is spilled, students will need to begin all over again. You might want to put a flat magnet on the bottom and have students use cookie sheets to prevent spillage. This kit does not include a solar panel, but does include a battery pack.

 

Introduction

Hydrogen fuel cells were first demonstrated when Robert Grove, an Oxford attorney, was experimenting with electrolysis. In the electrolysis process, an electric charge is applied to water with an electrolyte, resulting in hydrogen bubbles forming on a negatively charged cathode and oxygen bubbles forming on a positively charged anode. Grove wondered what would happen if he tried to operate electrolysis in reverse. In other words, if you present hydrogen and oxygen to an anode and cathode and an electrolyte, would you get electricity and water as the products? Fuel cells operate as electrolysis in reverse. Fuel cells using hydrogen as the fuel and oxygen as a reactant produce electricity, heat and water.

There are many ways to demonstrate electrolysis. In many science classes, students use pencil lead in salt water. In this basic experiment students will use a hydrogen fuel cell in reverse, as an electrolyser, to easily separate water into hydrogen and oxygen molecules. Students will be able to observe the two to one ratio of hydrogen to oxygen in water.

Objectives

   Students will know that different materials can be physically combined to produce different    substances.

   Students will know...

   - Materials made by chemically combining two or more substances have    properties that differ      from the original materials.
   - Materials may be made of parts too small to be seen without magnification.
   - The Periodic Table of Elements represents elements and that hydrogen and    oxygen are two of      those elements.
   - H is the symbol for hydrogen and O is the symbol for Oxygen.
   - Elements have electrons, protons, and neutrons. 
   - Atoms are basic units of matter.
   - A molecule is an electrically neutral group of at least two atoms.
   - One water molecule consists of two hydrogen atoms and one oxygen atom.
   - Students will use the scientific process to make discoveries.

Procedure

1. Explain atoms and molecules to students using the Periodic Table of Elements

The key points to cover include:

   - Atoms have electrons, protons and neutrons
   - Elements are atoms that have been defined by their atomic number
   - Electrons are positive
   - Protons are negative
   - Neutrons are neutral
   - The Periodic Table groups atoms/elements in rows by the number of electrons in their outer ring
   - The letters in a square on the Table of Elements are the chemical symbol for that element
   - The number to the top left of the letter represents the number of protons, or the atomic number      in the element.
   - The number at the bottom of the letter represents the atomic mass of the element which is the      number of protons added to the neutrons
   - Hydrogen can be joined with one other atom.
   - Oxygen can be joined with two other atoms.
   - A molecule of water is two hydrogen atoms joined with one oxygen molecule.
   - The chemical symbol of water is H2O.

2. Have students complete the first part of the Student Journal

Describe the equipment and process for electrolyzing water with a reversible PEM fuel cell. You will find specific instructions with whatever fuel cell kit you are using. Generally, you add a small amounts of water to both the hydrogen and oxygen sides of the fuel cell. You attach hydrogen and oxygen gas storage. This might be a cylinder, a syringe, a balloon or other storage. You apply electricity (Be sure to add the right amount of electricity - too much can damage the cell. In general, a single cell fuel cell will require 1.4 volts or one AA battery, a two cell fuel cell will use 2.8 or two AA batteries etc.). As soon as electricity is applied, hydrogen and oxygen will begin to be produced.

The key points to cover include:

   - Always match red (positive) wire to red connectors and black (negative) to black
   - Work with clean hands
   - Wear safety goggles
   - Always use distilled water
   - Be sure that the hydrogen side of the fuel cell is connected to the hydrogen storage
   - Be sure that the oxygen side of the fuel cell is connected to the oxygen storage
   - Check to be sure that electrical connections are solid
   - Once you connect the battery pack (or solar panel) to the fuel cell the reaction will begin      immediately, be ready to begin measuring. Hydrogen and Oxygen are not visible, so you need to      look for water levels to change, or syringes to move etc. depending on the type of storage you      are using.
   - Turn the battery pack off when you are finished experimenting

Have students conduct the experiment. Teams of three students work best. That allows for one student to act as timer, one as recorder, and one as observer. If you have more students per team, one student can observe hydrogen, one oxygen, one can record hydrogen data, one can record oxygen data and one can be the timer. Have students complete the chart on the Student Journal Page.

Before your students begin the experiment, read the Student Journal Page >>

 

Before the experiment, answer the following questions:

   - What is the chemical symbol of Hydrogen?
   - What is the chemical symbol of Oxygen?
   - How many hydrogen atoms are in one molecule of water?
   - How many oxygen atoms are in one molecule of water?
   - What is the chemical symbol of water?
   - In the following experiment you will separate water molecules into hydrogen atoms and oxygen      atoms. Do you think you will make more hydrogen, more oxygen, or equal amounts of each      element? Why?

Follow the instructions for setting up your experiment to electrolyze water.

Assign one team member to be the observer. This student will pay close attention to the levels of hydrogen and oxygen and will announce the levels of hydrogen and oxygen when the timer indicates 30 seconds have passed. Assign one team member to be the recorder. This student will write the amounts of hydrogen and oxygen the observer says out loud. Assign one team member to be the timer. This student will let the observer know when 30 seconds have passed and will continue to note each 30 seconds up to three minutes.

Time	Amount of Hydrogen	Amount of Oxygen
30 sec
1 min
1 min 30 sec
2 min
2 min 30 sec
3 min
Total

Answer these questions after you conduct your experiment.

   - Did you generate more hydrogen or oxygen during the 3 minutes?
   - What is the ratio of hydrogen to oxygen you generated?
   - Did you make the hydrogen and oxygen at a faster rate at the beginning, at the
     end, or was it an even generation over the 3 minutes?
   - Based on what you know about the hydrogen and oxygen atoms in a molecule of water, do these      results seem correct to you? Why or why not?