Anna Wetherholt 1
The Catalyst as an Instrument for Environmental Change
Current research related to topic: This is based off of current research by Professor Shannon
Stahl at the University of Wisconsin. Stahl’s research group is trying to develop effective
catalysts to be used in environmentally friendly reactions. Currently, both the pharmaceutical and
chemical industries are using catalysts which can be hazardous to the environment.
Learning objectives:
Students will be able to define a catalyst from the scientific perspective.
Students will illustrate and analyze the effects of the catalyst by performing scientific
experiments.
Students will employ their new knowledge to critically analyze the use of catalysts in large scale
factory productions.
Assessment criteria:
Students define catalyst as a substance that increases the rate of a reaction without being used up
during the reaction.
Students demonstrate proper lab technique during laboratory experiments.
Students utilize the lab results to develop an argument about which catalyst works best for a
given reaction.
Students analyze the results from the lab experiment to see how catalyzed reactions are similar
and different.
Students defend their opinion about the use of catalysts in large scale factory productions. They
utilize scientific language appropriately to express their thoughts and opinions.
Benchmark/Standard:
National Science Content Standard: Catalysts, such as metal surfaces, accelerate chemical
reactions. (NRC, 1996. Content Standard B: 3E, p 179.)
National Science Content Standard: Materials from human societies affect both physical and
chemical cycles of the earth. (NRC, 1996. Content Standard F: 4B, p 198.)
National Science Content Standard: Individuals and society must decide on proposals involving
new research and the introduction of new technologies into society. Decisions involve
assessment of alternatives, risks, costs, and benefits and consideration of who benefits and who
suffers, who pays and gains, and what the risks are and who bears them. Students should
understand the appropriateness and value of basic questions—"What can happen?"—"What are
the odds?"—and ''How do scientists and engineers know what will happen?" (NRC, 1996.
Content Standard F: 6D, p. 199)
National Science Content Standard: Human activities can enhance potential for hazards.
Acquisition of resources, urban growth, and waste disposal can accelerate rates of natural
change. (NRC, 1996. Content Standard F: 5B, p. 199)
National Science Content Standard: Designing and conducting a scientific investigation requires
introduction to the major concepts in the area being investigated, proper equipment, safety
precautions, assistance with methodological problems, recommendations for use of technologies,
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clarification of ideas that guide the inquiry, and scientific knowledge obtained from sources other
than the actual investigation. The investigation may also require student clarification of the
question, method, controls, and variables; student organization and display of data; student
revision of methods and explanations; and a public presentation of the results with a critical
response from peers. Regardless of the scientific investigation performed, students must use
evidence, apply logic, and construct an argument for their proposed explanations. (NRC, 1996.
Content Standard A2, p. 175)
Prior Knowledge/Prior Conceptions:
Students should have a basic understanding of chemical reactions.
Students should be able to calculate how much product should be formed in a chemical reaction.
Students should recognize the different types of chemical reactions (combination,
decomposition, single-replacement, double-replacement, and combustion) and be able to write
the missing product or reactants if given the other chemicals used in the reaction.
Students should understand that different chemical reactions proceed at different rates.
Students should recall that there are factors which affect reaction rates and should recall that
these factors are temperature, concentration, and particle size.
Students may have misconceptions about the definition of a catalyst. They may be most familiar
with the definition of a person or thing that causes an event or a change. Students may think that
some reactions could only happen with a catalyst and that the catalyst itself causes
Instructional strategies:
This lesson will consist of a mixture of instructional techniques. The lesson will first consist of a
demonstration of what catalysts can do. There will be a small interactive lecture portion in which
students learn exactly why a catalyst works. Following the lecture portion, there will be two days
of laboratory experiments. On the third day, there will be interactive instruction in which
students will discuss and then role play.
Instructional resources used:
Adapted from Middle School Chemistry by American Chemical Society, Lesson 6.5
(http://www.middleschoolchemistry.com/lessonplans/chapter6/lesson5)
Materials and set-up needed:
For demonstration:
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Hydrogen peroxide (30%)
Potassium iodide solution, 2 M
Liquid soap
Food coloring
Graduated cylinder (500 mL)
Safety glasses
Rubber gloves for clean-up
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For day one of laboratory experiments:
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Graduated cylinder (50 mL or 100 mL)
Hydrogen peroxide (3%)
Yeast
2 Popsicle sticks
Detergent solution
Dropper
For day two of laboratory experiments:
 Hydrogen Peroxide
 Detergent solution (this is best watered down or it just sits on top of the H2O2)
 Potassium Iodide (KI)
 Potato and celery pieces
 2 x 100 ml Measuring cylinders
 2 x Plastic Pipettes
 Spatula
 Tray
 Water
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Copper II sulfate solution (in cup)
Clear plastic cup (empty)
Salt
Piece of aluminum foil
Thermometer
Popsicle stick
Lab worksheets
For day 3: desks positioned into groups to promote active discussion
Time required: 3 class periods
Cautions:
When performing demonstration, teacher must wear safety goggles and lab coat. Students must
stay back because the hydrogen peroxide used in demonstration is severely corrosive, and the
catalyst used can also be hazardous if ingested. When performing laboratory experiments, all
students should wear long pants, close-toed shoes, safety goggles, and a lab apron. For the lab,
because the percent hydrogen peroxide is less, students should still be cautious but can actively
use the liquid for the experiment. On day 2, after the students complete the lab, the contents of
the cup should be allowed to evaporate. The solid is to be disposed of using local regulations
rather than just put into the trash or dumped down the sink.
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Instructional sequence:
Day One:
1. Introducing the Lesson
Begin with a demonstration of elephant’s toothpaste. This demonstration requires the teacher to
perform the following steps. (The following is adapted from Steve Spangler’s instructions for the
demonstration.) Ask nonsensical question: “If we wanted to brush an elephant’s teeth, where
could we get the toothpaste for it? Let’s make it!”
1.) The teacher puts on safety goggles and lab coat.
2.) Measure 20 mL of the 30% hydrogen peroxide into the graduated cylinder. It's best to
place the cylinder in a large tray to make the clean-up as easy as possible.
3.) Add a squirt of dish soap to the graduated cylinder containing the 30% hydrogen
peroxide.
4.) Add a few drops of food coloring
5.) The last step is to add 5 mL of the 2M potassium iodide solution (2M refers to the
molarity of the solution). The reaction takes place quickly, so it's important to stand back.
Because this is an actual demonstration, it is essential to ask students questions while preparing
the material as well as describe to students what exactly you are adding to the graduated cylinder.
Ask questions such as: “What do you guys think is going to happen?” “Why is this going to
happen?”
Anticipated answers include: An explosion. The two substances react together and form
an explosion.
Nothing is going to happen. I have used hydrogen peroxide before on a cut, and all it did
was bubble a little bit. Nothing is going to change this time.
Once the demonstration is complete, the following question will first be asked: “How do you
know that this was a chemical reaction?”
Anticipated student answers include:
Foam was produced. Foam is a type of gas. Gas is produced in chemical reactions.
Foam is not a type of gas! It’s a solid. But solids can be produced in chemical reactions.
There were bubbles in the foam. Bubbles are gas. Gas was produced.
There was a color change, wasn’t there? Color changes happen in chemical reactions.
After this, teacher will ask the question: “Why did this reaction work?”
Anticipated student answers include:
You used a stronger amount of hydrogen peroxide than we can get at the store. That’s
why it happened.
The extra chemical you added, that’s what changed it.
Does this have something to do with reaction rates that we talked about yesterday?
-Transition into body of the lesson (sample dialogue): So now we know that this is a chemical
reaction because a gas was produced. You can buy hydrogen peroxide that isn’t as strong as this
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was at the store. We have made hypotheses why this reaction worked, but we still don’t know
exactly how it worked. Let’s explore together why the reaction worked.
2. Body of the Lesson
-Write down the chemical formula for hydrogen peroxide on the board. H2O2. Ask students if
this chemical formula looks like one that they have seen before. Students should respond that it
is similar to H2O which is the chemical formula for water.
-Explain that hydrogen peroxide is not a very stable compound which means that it will break
down on its own if given time. Have bottle of store-bought hydrogen peroxide. Have students
notice the color of the bottle. Ask students why the bottle is like color.
Anticipated answers include: It’s more decorative.
Does it stop the chemical from breaking down?
-Tell students that hydrogen peroxide is so unstable that even the energy that comes from light
can cause the hydrogen peroxide to decompose faster than normal. Ask students: “Remember
what we learned previously about rates of reactions. What would explain this?”
Anticipated answers include: Heat is a form of energy. If temperature is increased, the
rate of reaction happens faster.
-Explain that the container is opaque to prevent most light from coming through. Otherwise, the
hydrogen peroxide would decompose over time.
-Write down the chemical reaction on the board. 2 H2O2  2 H2O + O2
Explain that the hydrogen peroxide decomposes into water and oxygen according to this
chemical reaction equation.
-At this point, explain that you added something called potassium iodide to the solution in the
demonstration. Go into explanation that a catalyst is a substance that speeds up the rate of the
reaction but doesn’t change in the reaction. Explain that potassium iodide is a catalyst. Ask
students: if potassium iodide was used in the chemical reaction, why isn’t it written in the
chemical reaction?
Anticipated answers include: Because a catalyst doesn’t change in the reaction.
It would be included in both the products and reactants side. It is not used up in the
reaction.
Affirm answers that are correct. The substance increases the rate of the reaction, but it isn’t used
up in the reaction so it’s not included.
-Ask students “Can other substance catalyze the decomposition of hydrogen peroxide?” Expect
students to answer yes or no. Ask students: “how can we see if other substances work as a
catalyst?” Students should answer with experiment.
Explain that students will be doing an experiment to see if other substances speed up the
reaction. Tell students that they are going to try catalyze the decomposition of hydrogen peroxide
with a different substance. Go over the basic steps with the students before the students work
with lab partners.
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-Students should work with lab partners (groups of 2, maximum 3). Students receive activity
worksheet and materials required for activity should be already set out on the lab tables.
Students follow the following steps:
1. Add 10 mL of hydrogen peroxide to a graduated cylinder. Add 1 drop of detergent
solution. Swirl gently and watch the solution for any bubbling.
2. Use the end of the Popsicle stick to add a small amount of yeast to the hydrogen
peroxide and swirl cylinder.
3. Place cylinder on the table and watch for any bubbling.
4. Feel the cylinder to see if there is any temperature change.
Notes for teacher: It is important that students realize that detergent is only added so that if a gas
is produced, students can easily observe bubbles which show that a gas is present. Before the
yeast is added, there should be no observable bubbling. Once the yeast is added, the solution
should bubble up the graduated cylinder. The graduated cylinder should also feel slightly
warmer.
Activity sheet will include following questions:
1.) Is this a chemical or a physical reaction? How could you tell? Describe what you saw.
2.) What was the catalyst in this reaction? What proof do you have for this?
3.) Write the equation for this reaction. Where would you put the catalyst in the
equation?
For full points, the answers should include the following:
1.) Chemical reaction, gas was produced, bubbles were formed
2.) Yeast, bubbles formed after yeast was added
3.) H2O2  H2O + O2 . Yeast shouldn’t be put on either side of the reaction. Students
will still be rewarded points if they put yeast on both sides of the chemical equation
although this will need to be addressed as a whole class. (From instructions, students
should realize that yeast shouldn’t be included on either side. If they did not gather
this, teacher must clarify this the next day.)
Partial points will be awarded for well thought out explanations that may not necessarily be
correct.
-If there is more time, students can try other substances to use a catalyst such as water to
demonstrate that not all substances work as catalysts.
-Students clean up. All products are safe to dump down the sink.
3. Wrapping Up the Lesson
-Regroup students and ask the question again: “Earlier in the class period, we wanted to know if
other substances can catalyze the decomposition of hydrogen peroxide. After this investigation,
do we know the answer to this? How do we know?”
-Anticipate students describing the lab results that they saw. If students had time to use
other substances, anticipate that students will respond with “some substances can but not
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all work as a catalyst.”
-Students complete exit slip. Students write down two things they learned from that day.
4. Evaluating Learning
-By the end of day 1, the students should be able to define a catalyst from the scientific
perspective. This will be double checked on day 2 with the opening question.
Anticipated answers to “what is the definition of a catalyst?”
-A substance that is used to increase reaction rate without being used up in the reaction.
-A catalyst changes the rate of the reaction.
-Something that causes a reaction to go forward.
Students should have similar answers to these. The first answer is the most preferable definition
for a catalyst. Students should also acknowledge that while these reactions could take place
without a catalyst, it would take a much longer time to proceed forward if this was the case.
Day Two:
1. Introducing the Lesson
Play the video “Genie in the Bottle” located here:
http://www.middleschoolchemistry.com/multimedia/chapter6/lesson5#genie_in_a_bottle (the
video will have been downloaded onto flashdrive). Ask students how this is similar to what they
saw yesterday. Anticipated answers include: “it’s another reaction that uses a catalyst; this also
decomposes hydrogen peroxide.” Because the students turned in exit slips the previous day, the
teacher will clarify any misconceptions the students identified from the lab and demonstration
the previous day. Teacher will also ask student questions: “What is the definition of a catalyst?”
and “How was the video today similar to the elephant’s toothpaste demonstration we saw
yesterday?” This will allow for students to refocus and remember what was done the previous
day.
Anticipated answers to “what is the definition of a catalyst?”
-A substance that is used to increase reaction rate without being used up in the reaction.
-A catalyst changes the rate of the reaction.
-Something that causes a reaction to go forward.
Anticipated answers to “How was the laboratory experiment yesterday similar to the
elephant’s toothpaste demonstration we saw yesterday?”
-In both, we used hydrogen peroxide. We used a catalyst in each reaction to allow the
hydrogen peroxide to decompose faster than it normally would.
-Both used a catalyst to speed up the reaction. Both used hydrogen peroxide.
-Both were examples of chemical reactions. In both, hydrogen peroxide decomposed to
oxygen and hydrogen molecules. Because these substances are different than hydrogen
peroxide, a chemical reaction took place.
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2. Body of the Lesson
-Sample transition: now that we have seen a few different substances that are used as a catalyst
in the decomposition of hydrogen peroxide, this leads us to a different question. Which one of
these substances is the best catalyst? How do you judge which one is the best catalyst? We’ll be
investigating that today in the lab.
-Introduce lab. Explain to students that they will be experimenting to see which substance works
the best for decomposing hydrogen peroxide. Explain that they will be using a number of
different catalysts: potatoes, celery, potassium iodide, and yeast.
-Day continues with laboratory experiments. Students first experiment with different catalysts for
the same reaction. Potatoes and celery contain the catalyst known as catalase (which is also
found in humans). Students will also use yeast and potassium iodide as catalysts. The students
will investigate to see which is the best catalyst. Suggest to students they can judge which one is
best by how fast the reaction goes (have stop watches set up for this) or by how much gas was
produced in the reaction (students can measure by volume with number or by using sight)
Students use potato, celery, potassium iodide, and yeast in separate graduated cylinders.
1. Pipette 10 ml of hydrogen peroxide into each measuring cylinder on the tray.
2. Add a few drops of detergent solution to each measuring cylinder.
3. Drop a piece of potato into the first measuring cylinder and record what happened
4. Add a piece of celery into the second graduated cylinder and record what happened.
4. Add a spatula of potassium iodide to the third measuring cylinder and record what happened.
5. Add yeast to the 4th measuring cylinder and record what happened.
6. Wash everything up (solutions can go down the sink.)
Students should answer the following questions.
1.) Compare each of the reactions to each other. How were they similar? How were they
different? (All of the reactions were a chemical reaction of hydrogen peroxide
breaking down. Each reaction, however, had a different catalyst.)
2.) Which catalyst was best? How do you know? (The potassium iodide should have
been the best [the reaction preceded most quickly]. However, any answer which
provides a reasonable explanation of what happened should be accepted.)
-After the experiment is cleaned up, the students will do a second activity with a completely
different reaction which also uses a catalyst.
-The students follow the following procedure:
1.) Place the piece of aluminum foil in an empty cup. Use your fingers or a Popsicle stick to
push the foil firmly down so that it lays flat and covers the bottom of the cup.
2.) Add all of the copper II sulfate solution to the cup with the aluminum foil.
3.) Gently swirl the solution for a few seconds and let it stand still. Watch the aluminum for
any bubbling or color change.
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4.) Use your Popsicle stick to place a small amount of salt in the copper II sulfate solution.
Gently swirl the solution for a few seconds and let it stand still. Watch for any bubbling
or color change.
5.) Carefully place a thermometer in the solution to see if there is any temperature change.
[Expected Results: Before the salt is added, nothing should be happening. After the salt is added,
the color turns greenish and bubbles begin to form on the aluminum. Copper (brown) begins to
form on the aluminum. The solution gets warmer.]
-Students will answer the following questions:
1.) How do you know that a chemical reaction took place? Give at least two ways.
(A gas was produced, there was a color change, there was an increase in
temperature, and a solid was formed.)
2.) What is the catalyst in this activity?
(Salt)
3.) How was this similar to the experiment we did earlier today? How is that different?
(This was a different reaction completely. The reaction, however, still required the
use of a catalyst. In this case, a solid was produced as well as a gas.)
-At the end of day 2, students come back together. As a class, we discuss the last question
together. Students turn in worksheet for activity 2. Students are assigned homework for the lab
report for the investigation of which catalyst worked best. The lab report presents the
investigated question, cautions used, the procedure used, the observations seen, a conclusion, and
the questions answered.
3. Wrapping up the Lesson
Students come back together, and we discuss the activity questions together. We first talk about
how we knew a chemical reaction took place, what the catalyst was, and then finally how was
the second experiment similar to the first experiment we did today? How is it different? Students
should recognize that the two reactions were completely different reactions, but both of them
used a catalyst. This allows students to see that different reactions can use catalysts as well, and
the use of a catalyst is not always to speed up the decomposition of a reactant.
4. Evaluating Student Learning
-By the end of day 2, students will illustrate and analyze the effects of the catalyst by performing
scientific experiments. This will be evaluated by the turned in lab report and worksheet for the
experiments/activities performed on day 2.
For lab report, the following questions must be answered:
1.) Compare each of the reactions to each other. How were they similar? How were they
different? (All of the reactions were a chemical reaction of hydrogen peroxide
breaking down. Each reaction, however, had a different catalyst.)
2.) Which catalyst was best? How do you know? (The potassium iodide should have
been the best [the reaction preceded most quickly]. However, any answer which
provides a reasonable explanation of what happened should be accepted.)
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For the activity:
1.) How do you know that a chemical reaction took place? Give at least two ways.
(A gas was produced, there was a color change, there was an increase in
temperature, and a solid was formed.)
2.) What is the catalyst in this activity?
(Salt)
3.) How was this similar to the experiment we did earlier today? How is that different?
(This was a different reaction completely. The reaction, however, still required the
use of a catalyst. In this case, a solid was produced as well as a gas.)
The activity answers will be discussed in class which allows for students to check their
understanding. The lab report questions along with the lab report must be completed outside of
the classroom. The lab report is a summative assessment while the activity is a formative
assessment.
Day Three:
1. Introducing the Lesson
Because day 3 is structured a little bit differently from the other two days, day 3 will begin with
this youtube video which is an introduction to the concept of green chemistry.
http://www.youtube.com/watch?v=JD9FgLOTPE0 This video allows for a basic introduction
into the idea of green chemistry and will allow for students to make connections to the
importance of green chemistry when using catalysts. The teacher will ask the following question:
“Why is it important that catalysts be considered green?”
Anticipated answers include:
Catalysts are not used up in the reaction. So if there is a hazardous material, it will
remain rather than be made into something else.
But if catalysts aren’t used up in the production, why can’t we just reuse them again and
again? Wouldn’t that still be environmentally friendly?
2. Body of the Lesson
-After having two days of learning about catalysts in reactions in both the body and outside the
body, students are ready for extracting meaning and applying knowledge to scientific situations
that are currently happening.
-Begin with an introduction to Green Chemistry. The video introduces the idea of green
chemistry pretty well. Further define green chemistry as a branch of chemistry is concerned with
developing processes and products to reduce or eliminate hazardous substances. One of the goals
of green chemistry is to reduce pollution at the source rather than deal with pollution after it has
already occurred.
-If this question was not asked to response of the opening question, the teacher should ask the
following question: But if catalysts aren’t used up in the production, why can’t we just reuse
them again and again? Wouldn’t that still be environmentally friendly?
Anticipate student confusion and anticipate difficulty of understanding. Ask students to relate
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back to day 2. What was the catalyst we used yesterday? What did the reaction produce?
Anticipated answers: The catalyst was salt. The reaction produced a brownish solid.
Then ask the students: Even though the catalyst was not used up in the reaction, could you easily
separate the salt from the brown solid at the end? The answers should be a resounding “no”
throughout the class.
Then pose the question: “So if you cannot easily separate the catalyst from the reaction, what
would that mean if we were doing this on a large scale production?”
Anticipated answers include: It would be expensive to remove all of the catalyst from the
product.
We might not be able to get all of the catalyst out of the product.
If we couldn’t get all of the catalyst out of the product, if the catalyst was bad for the
environment, it would probably be bad for us too. There would be catalyst left in the
product, and we could get sick.
At this point in the lesson, students should realize why we need environmentally friendly
catalysts.
-Explain that there are several people currently researching environmentally friendly catalysts.
Most of the catalysts currently used are transition metals which have been found to be toxic to
the environment. These scientists are trying to find other catalysts which have not been found to
be hazardous to the environment. One group is trying to use molecular oxygen as a catalyst. This
is not damaging to the environment, and only a small amount of the catalyst is needed.
-At this point, students participate in dramatization of an environmental court case regarding the
use of catalysts which can be harmful to the environment. The class is split into 4 groups where 3
students in each group receive the prosecutor’s side while the other 3 receive the defendant’s
side. (*Note*- Depending on the students in the class, it may be necessary to introduce the
concept of a court case to some students.)
The prosecutor’s side receives the following:
Wetherholt Pharmaceutical Company has recently begun producing a new medication to
treat a rare type of cancer. The company, however, uses a transition metal catalyst to help
produce the medication. This transition metal has been found to be extremely hazardous
to the environment. Because of this, you have issued a class action lawsuit against them
ordering them to stop the production of this medication because of how it is being made.
You must argue your side.
The defendant’s side receives the following:
You work for Wetherholt Pharmaceutical Company and have recently began mass
producing a new medication which has been found to help treat a rare type of cancer.
You have found a catalyst which helps speed up the reaction, but the catalyst has been
found to be damaging to the environment. You have been researching other catalysts
which can speed up the reaction but have not found an environmentally friendly catalyst
yet. You are arguing that because you are currently trying to find a catalyst which meets
these requirements, you should be allowed to continue to produce the medication this
way for now. You argue that the benefits outweigh the risks.
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Each group forms a trial. The groups of students must work together in order to argue their side
of the court case. The students need to know that this is a role-playing activity, and any
disagreement is not personal. The students should also use scientific language in their
explanations. This activity should last for approximately 15-20 minutes.
-After each individual group has finished arguing the court case, the class will come back
together to present the overall sides of the court case.
-The students should come up with an overall consensus over the difficulty of the situation. The
students should feel a sense of tension recognizing that on one hand, people are getting better
form cancer, but on the other hand, the environment is being destroyed (which ultimately affects
people’s health). Students should obtain understanding of the difficulty that some pharmaceutical
companies go through in incorporating overall needs. Students will evaluate the difficulty of the
situation and discuss as a whole.
3. Wrapping up the lesson:
The overall lesson will be wrapped up on the last day with the remaining time period.
After the mock court case, we will have an overall discussion about why we would want to use
catalysts in the first place and why it is so important to use the right catalyst for the reaction.
Sample dialogue includes: “Why would big companies want to use a catalyst for a reaction?”
“The reaction would go so slowly otherwise that it wouldn’t make sense for the company to make
the product at all.” “Catalysts increase the rate of the reaction which means that companies can
make more product in less time.”
“Good, that’s exactly right. Now why is it so important that we find the right catalyst for
the reaction?”
Some catalysts make the reaction go faster than other catalysts do, but certain catalysts
are harmful to the environment.
Because some catalysts are harmful to the environment and hard to remove from the
products
We have to weight the risks of using the catalyst and the rewards of using it. It could
make a reaction go very fast, but it could also really harm the environment. We need to
find a compromise.
The discussion about the importance of using environmentally friendly catalysts in the
large scale production of chemicals will primarily be a good way to end the overall lesson.
Sample teacher dialogue includes: “By this point, you have seen that many catalysts can work for
the same reaction, just at different rates. This means that environmentally friendly catalysts can
be found that work for a reaction that was previously catalyzed by a harmful catalyst. While the
catalyst is not used up in the reaction, it can be hard to obtain all of the catalyst back from the
reaction because of production of solids. As you saw in the court cases, scientists have a difficult
decision to make sometimes about their new product. While the new product could really help a
lot of people, it could also hurt a lot of people. For scientists, they have to weigh the risks and
rewards and make a decision upon that. All of you have to do the same thing when making a
decision.”
On the last day of the 3 day lesson, the students will be given an exit slip which will
require them to list 4 things that they have learned about catalysts.
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4. Evaluating learning:
-On Day 3, the students defend their opinion about the use of catalysts in large scale factory
productions. They utilize scientific language appropriately to express their thoughts and
opinions. This will be evaluated by the teacher as the teacher circulates throughout the room.
Each student should participate in the discussion at least once at the table (preferably more than
that, but this allows for differentiation for students who have a difficult time talking in class).
Each group should be on task and should be actively engaged in discussion. If students have
questions, rather than get off-task, they ask teacher for help or clarification.
Design Rationale:
The three day lesson plan is structured mostly using hands-on activities. While my
students could simply learn about a catalyst, my students are actually seeing how catalysts can be
used to increase reactions rates. The demonstration of the elephant’s toothpaste is a dramatic
example of how a chemical reaction rate will be increased by adding a catalyst to a reaction. The
demonstration allows for students to see a very clear example of a catalytic reaction.
By then explaining the example in terms of catalysts, students can gain further
understanding of how the reaction proceeds and why the reaction proceeds that way. After
learning about this, the concept will be reinforced by doing a similar reaction with yeast. The
students will be able to see as well that different substances can catalyze the same reaction with
different effects (i.e. at different rates).
By utilizing potatoes and celery on the second day, students are able to see that cells
contain a catalyst as well which will speed up the breakdown of hazardous chemicals produced
as by-products in body reactions. This concept was introduced on the first day at the end, but
reintroducing this on day 2 with clear scientific experiments of it happening, students will gain
more understanding. Because this can be a difficult concept to understand, the visualization
allows for a clearer picture of what is happening. Students learn by similarity that this reaction
occurs inside of their body to break down any hydrogen peroxide produced as a product in any
important reactions.
The use of exit slips each day allows for formative assessment. This allows for the
teacher to change the lesson plan accordingly when the students do not understand a concept.
The activity worksheets also allow for formative assessment to take place. The summative
assessment of the unit is the lab report that students must complete, and students will receive
feedback on the worksheets in class each day before the lab report is due. This allows time to
correct any misconceptions that students may have about what has been taught.
The use of the court case activity is to promote higher order thinking in the students and
promote the idea of applicability in every day life for science. This is also a form of summative
assessment. The students must take what they have learned each day of this lesson and apply it to
the situation presented. The situation presented is similar to a real life dilemma that some
companies may face (while it may not be in law suit form). The emphasis of the activity is for
students to apply what they have learned to a situation that is outside of the science classroom.
By putting students into a real life situation, the students can see that the science that they are
learning in the classroom can apply to other jobs that they may have in the future.