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The Green Computer Decision
ACTIVITY OVERVIEW
T
TA L K I N G I
Students use their understanding of the chemistry of materials and product life cycles
to evaluate computer proposals for a school district. In the role of materials scientists,
students consider four proposals and, based on the advantages and disadvantages of
each, choose which plan a school district should accept as it purchases computers
with money from a “Green Computer Grant.”
KEY CONCEPTS AND PROCESS SKILLS
(with correlation to NSE 5–8 Content Standards)
1.
The progression from the manufacture, to the use, and through to the disposal of
a product is referred to as a product’s life cycle. The waste generated during a
product’s life cycle may change form (e.g., through incineration), but it cannot
disappear. (PhysSci: 1)
2.
Disposing of consumer products can create toxic-waste problems. (Perspectives: 1)
3.
Making decisions about complex issues often involves trade-offs. (Perspectives: 4)
KEY VOCABULARY
evidence
life cycle
raw materials
manufacturing
useful life
end of life
trade-off
B-205
Activity 29 • The Green Computer Decision
MATERIALS AND ADVANCE PREPARATION
For the teacher
*
1
transparency of Student Sheet 29.3, “Comparing Computer
Proposals”
1
Scoring Guide: GROUP INTERACTION (GI) and/or
1
Scoring Guide: COMMUNICATION SKILLS (CS) and/or
1
Scoring Guide: EVIDENCE AND TRADE-OFFS (ET) and/or
1
overhead projector
For each group of four students
*
1
transparency of Student Sheet 29.1, “Life Cycle of a Computer”
1
poster board or chart paper
*
assorted colored poster pens
*
tape
*
paper towels for cleaning transparencies
For each student
1
Student Sheet 29.1, “Life Cycle of a Computer”
1
Student Sheet 29.2, “Analyzing a Computer Proposal”
1
Student Sheet 29.3, ”Comparing Computer Proposals”
1
Student Sheet 13.1, “Principles of Green Chemistry,” from Activity
13, “Product Life Cycle”
1
copy of Scoring Guide: GROUP INTERACTION (GI) (optional) and/or
1
copy of Scoring Guide: COMMUNICATION SKILLS (CS) (optional) and/or
1
copy of Scoring Guide: EVIDENCE AND TRADE-OFFS (ET) (optional)
*Not supplied in kit
Masters for Scoring Guides are in Teacher Resources III: Assessment.
Make eight transparencies of Student Sheet 29.1, “Life Cycle of a Computer.”
Assign groups one of four proposals: A, B, C, or D. You may wish to do this in advance.
Note that while groups will analyze one proposal in depth, after the class presentations, students will make an individual choice as they complete Analysis Question 2.
TEACHING SUMMARY
Getting Started
1.
Introduce the “Green Computer” decision.
2.
Students summarize the stages in the life cycle of a computer.
Doing the Activity
3.
(GI ASSESSMENT) Student groups analyze one computer proposal.
Follow-Up
B-206
4.
(CS ASSESSMENT) Groups prepare and present their proposal analysis to the class.
5.
(ET ASSESSMENT) Students consider evidence and trade-offs as they make a decision
about which computer proposal to recommend.if this works)
The Green Computer Decision • Activity 29
TEACHING SUGGESTIONS
GETTING STARTED
1.
Introduce the “Green Computer” decision.
To relate the challenge of this activity to students
lives, begin the class by asking students, How do you
or your family decide on which products, such as a
TV, stereo, cell phone, or computer, to buy? Students’
responses may include price, reliability, quality,
appearance, and features, as well as recommendations from friends or consumer-research groups.
Encourage students to elaborate on their responses
by identifying specific criteria for selecting a product. List these criteria on the board.
Then relate this decision to the context posed in this
activity by asking the class, If you were purchasing
computers for a school or an entire school district,
how would you decide which computers to buy?
Would your criteria change? List they suggest on the
board. Their responses might include criteria suggested, along with criteria specific to a school such
as reduced prices for purchasing computers in bulk,
computers that come with programs that schools
can use, and student-friendly computers.
Ask students, Consider what you’ve learned in this
unit about the toxic waste produced during a computer’s life cycle. How might this knowledge affect
your decision to purchase a computer? Students may
mention that they will take more time to do
research about the life cycle of a product, including
the amount and types of waste produced in its manufacturing and at the end of its life before purchasing a product. Some students may say that their
decision-making process won’t change because it
would be inconvenient to do things differently, or
take too much time or be difficult to find substantial
information.
To set the context for the decision students will
make in this Activity, explain that many organizations are beginning to alter their purchasing decisions to factor in a product’s production process, the
raw materials needed to make it, and its end-of-life
options. In this activity, it is exactly this information
that they will use as evidence to make a decision
about purchasing computers.
Read the introduction and Challenge with the class.
In this activity, students will play the role of materials scientists and evaluate one of four proposals to
purchase computers. The money that will be used to
buy the computers is from a “Green Computer
Grant,” meaning that the proposal chosen must
minimize the negative environmental impact of the
computer. Taking on the role of a materials scientist, the students’ task will be to identify how a computer proposal meets green criteria and improves
on the typical computer life cycle.
Review with students Student Sheet 13.1, “Principles
of Green Chemistry,” from Activity 13, “Product Life
Cycle,” because students will be asked to show how
each proposal meets these guidelines and incorporates the science principles that they’ve observed in
the activities in this unit.
2.
Students summarize the stages in the life
cycle of a computer.
Procedure Step 1 introduces the life cycle of a computer. Distribute a transparency of Student Sheet
29.1, “Life Cycle of a Computer” to each group. Students will use it in Procedure Step 1 to identify and
label the stages in the life cycle of a computer.
Understanding the stages involved and their relationship to each other ensures students have the
background information they will need to analyze a
computer proposal in Procedure Step 4 and will use
it again in Procedure Step 6 when they present
information to the class. Project a transparency of
Student Sheet 29.1, “Life Cycle of a Computer,” to
review the correct placement of each term.
DOING THE ACTIVIT Y
3.
(GI ASSESSMENT) Student groups analyze one
computer proposal.
Ask the class, What should the school board members consider when deciding which proposal they will
select to purchase computers? Students’ responses
are likely to include the number of computers
needed, how well the computers work in the class-
B-207
Activity 29 • The Green Computer Decision
room, how easily the students can use the computers, the computers’ operating systems (including
memory and processing speed), and the peripherals included with the system.
Direct students back to the criteria they listed in
Teaching Step 1. Tell students that in this activity
they will perform a life-cycle analysis of one of four
proposals. This means that they will explain how
each feature of the computer proposal will reduce
the environmental impact of the computer.
Procedure Step 2 takes students through the steps
involved in conducting a life cycle analysis with a
hypothetical new polymer. This is an opportunity
for student groups to practice the cause and effect
thinking that they use to explain how one proposal
feature might affect several stages in the life cycle of
the computer. Based on the needs of yours students,
you might model this thinking. Show students how
to refer at Student Sheet 29.1, “Life Cycle of a Computer,” and ask how the life cycle might change if
the new plastic is used. They might say, “If the
plant-based polymer is used, when the computer is
recycled it is likely that there will be less toxic waste
produced. It is also likely that less oil will be needed
as a raw material.” Emphasize that this is the type
of thinking they will perform as they analyze their
assigned computer proposal.
minimizes possible harm to the environment from
its products. Assign groups one of the four proposals, A, B, C, or D. Review with students the concepts
contained in the proposals and any vocabulary that
they are not accustomed to. Discuss the meaning of
words that might impede their analyses or suggest
how they can find definitions, such as looking up
the words in a dictionary or on the Internet.
Distribute Student Sheet 29.2, “Analyzing a Computer Proposal.” This sheet provides a place for student groups to record the features of their assigned
proposal and how it affects the life cycle of the computer. Note that each line should be used for one
feature of the proposal, but will result in multiple
affects on the life cycle of the computer. You may
choose to assess students’ ability to work in groups
using the GROUP INTERACTION (GI) Scoring Guide. For
more information on this assessment variable, see
Teacher Resources III: Assessment.
Sample student responses to Student Sheet 29.2 follow. Students will likely come up with many more
ways that the life cycle will be affected than are
shown on the next page.
FOLLOW-UP
4.
(CS ASSESSMENT) Groups prepare and present
their assigned proposal analysis to the class.
Explain the specifics of the school district’s plan.
The district has two middle schools, and it wants to
purchase two sets of 30 computers (60 computers
per school) for each of the schools. This will allow
them to set up two computer labs in each school. Be
sure that students understand that the proposals do
not include specifications such as memory, processing speed, or price—factors that are commonly the
top three when individuals are considering purchasing a computer. This is because these factors
are assumed the same for the computers in all four
proposals. The materials scientists will only evaluate the ways in which each proposal meets the
green requirements.
Before students begin working on Procedure Step 4,
let them know that each group will give an oral
presentation about its assigned computer proposal.
They will need to decide on the format of their presentation and how they will use a transparency of
Student Sheet 29.1, “Life Cycle of a Computer,” to
illustrate how the proposal modifies the life cycle of
the computer. Prompt them to look at the image on
Student Sheet 29.1, and then point to areas of the
image as they talk about how each feature of the
proposal would change part of the life cycle. They
should highlight the key features from the information they have recorded on Student Sheet 29.2,
“Evaluating a Computer Proposal.”
Remind students that when buying the computers,
the district will have to identify how the proposal
(company) they select is “green,” that is, how it
To offer guidelines on oral presentations, see
Teacher Resources II: Diverse Learners. You may
score groups’ presentations using the COMMUNICA-
B-208
The Green Computer Decision • Activity 29
Sample Responses to Student Sheet 29.2. “Analyzing a Computer Proposal”
Proposal A
Proposal feature
How it affects the life cycle of a computer
Reuse of copper from
circuit-board production
• Fewer raw materials are needed because some of the copper will be reused.
Recycled glass used for
monitor
• Reduces need for raw materials to make new glass.
Reduced packaging for
computers bought in
bulk
• Fewer materials need to be manufactured to package the computer.
• There will be less copper chloride waste to dispose of.
• Reduces amount of glass material that will end up in landfills.
• Fewer raw materials are needed to make the packing materials.
• Fewer packing materials end up in landfills.
Proposal B
Proposal feature
How it affects the life cycle of a computer
Old computers shipped
back to company
• Materials like wires and metal pieces can be reused for new computers.
• Fewer raw materials are needed to make new computers.
• Reduces the materials in landfills from people throwing out their computers in the
garbage.
Hazardous materials sent
to hazardous-waste facilities
• Fewer hazardous wastes are put into landfills.
Plant-based-plastic
monitor casing
• Reduces the amount of petroleum-based plastic materials needed to make the
computer case.
• Much less toxic to throw out a plant-based plastic than a petroleum-based plastic.
Proposal C
Proposal feature
How it affects the life cycle of a computer
Liquid crystal display
(LCD) monitor
• Uses 50% less electricity.
Metals reclaimed from
waste solutions
• Fewer raw materials are needed because some of the copper will be reused.
15% of plastic
components made of
recycled plastic
• Fewer raw materials from the earth were needed to make the new computer.
• There will be less used copper chloride waste to dispose of.
• Less garbage was dumped because some of it was recycled to make the plastic
components of this computer.
• Materials like metal wires and metal pieces can be reused for new computers.
Company takes back
computers
• Fewer raw materials needed to make new computers.
• Reduces the materials in landfills from people throwing out their computers in the
garbage.
B-209
Activity 29 • The Green Computer Decision
Proposal D
Proposal feature
How it affects the life cycle of a computer
Liquid crystal display
(LCD) monitor
• Uses 50% less electricity.
• Fewer materials need to be manufactured to package the computer.
Computers shipped in
bulk.
• Fewer raw materials are needed to make the packing materials.
• Fewer packing materials end up in landfills.
Recycled metal used
50% coupon if computer
is kept for at least 8 years
• Less metal as raw materials taken from earth’s surface.
• Reduces the amount of metal that is in landfills when the computer is thrown away.
• This encourages the district to upgrade and keep using the current computer, which
reduces the need to buy a new computer, which reduces the amount of materials
needed to make the new computer.
SKILLS (CS) Scoring Guide. Note that in this format the scoring will apply to the group. Distribute
and review the scoring guide as needed. Encourage
groups to make posters or find or create illustrations
to accompany their presentations. Stress that the
evidence and ideas they discuss are crucial to a
good presentation. It is more important that students choose illustrations that highlight their evidence than ones that just enhance the
attractiveness of their presentations. For information on facilitating group work, see the Facilitating
Group Interaction section of Teacher Resources II:
Diverse Learners.
TION
Distribute Student Sheet 29.3, “Comparing Computer Proposals.” As students listen to each group’s
presentation about their assigned proposal, they
should record the ways the proposal alters the life
cycle of a computer. Stress the importance of this
information in that students will use the evidence
they individually record on this sheet at the end of
the activity to make a decision about which proposal to recommend to the school district. Student
responses on Student Sheet 29.3 should incorporate
information from each computer proposal. The
information for individual proposals A, B, C, and D
can be found on pages 209 and 210.
B-210
5.
(ET ASSESSMENT) Students consider evidence
and trade-offs as they make a final
decision about which computer proposal
to recommend.
Review with the class the advantages of each of the
four computer proposals. You may wish to display a
transparency of Student Sheet 29.3, ”Comparing
Computer Proposals,” and summarize students’
ideas on the advantages of each of the four proposals. Stress that when they answer Analysis Question
1 they will include evidence from this sheet to support their decision. This is similar to the process
they undertook when selecting a glass cleaner in
Unit A, Activity 11, “Choosing a Cleaner.”
Analysis question 2 is crucial in that it compels students into making a connection between the science concepts they have worked with in this unit to
the green computer decision. Encourage them to
look back to their Analysis Question answers in
prior activities.
Analysis Question 3 asks students to consider additional consumer information, namely cost. At this
point, it will become apparent that purchasing the
computers according to the proposal with the most
environmental protections will cost the most. This is
often a reality when considering the purchase of
“green” products. Ask the class to discuss how this
would change the decision they wrote down for
Analysis Question 1. Guide the discussion to considerations of short-term increases in cost to con-
The Green Computer Decision • Activity 29
sumers versus a product’s long-term environmental
cost. Consider starting a discussion by asking, If
green products are better for us and the environment,
what do we do if they are more expensive?
Current methods of treating waste including
dilution, incineration and reclamation can
change waste, but does not “get rid of” potentially toxic heavy metals.
In today’s society, products that are greener tend to
cost more, discouraging most consumers from buying them. Even though green products seem like a
good idea, they have not yet been embraced, partly
because of their high price. Use Analysis Question 4
to help the class explore what they think about this
obstacle and brainstorm what might possibly be
done to change the situation.
3. The proposals your group analyzed did not include
the cost of each computer. The school board members did not provide this information earlier because
they wanted you to evaluate the plans based only on
the chemistry of materials and the products’ life
cycles.
SUGGESTED ANSWERS TO QUESTIONS
1.
(ET ASSESSMENT) Which proposal would you recommend the district choose for its Green Computer
Grant? State your opinion, citing evidence from Student Sheet 29.3, “Comparing Computer Proposals,”
and previous activities. Include a discussion of the
trade-offs involved in your decision.
Student answers will vary. Their choice of either
Proposal A, B, C, or D should be backed with evidence from the proposals and group presentations in the form of features from the chosen
proposal and an explanation of why that feature is beneficial. Since students are comparing
the impact of the proposal on the computer life
cycle, the trade-offs discussed should include an
explanation of the different stages in this computer life cycle and how they are affected.
2.
With your group, explain how the science
you learned in this unit helped you analyze
your proposal. To do this, choose one feature of your
proposal and explain which concept you learned
helped you to understand that this feature would
improve the life cycle of a computer.
Read the list price for each computer proposal below
(In Student Book).
Knowing the price of each computer, does your
answer to Analysis Question 1 change?
Students’ answers will vary. Answers are likely to
indicate that students’ decision to buy a greener
computer will be influenced by price, meaning a
lower price is more desirable than an green
option.
4. Reflection: Do you think that there should be green
guidelines for families and individuals when they
buy electronic products such as computers?
Student’s answers will vary. They are likely to
mention cost, personal choice, and access to
information in stating their opinions. A sample
answer follows:
I do not think there should be green guidelines
as laws. But it is important that we all consider
how each purchase we make might damage the
product might do to the environment. For this
reason, maybe there should be a reward or
coupons for buying green products that will
make families and individuals want to consider
green guidelines when they buy electronic
products.
Answers will vary by proposal and by feature.
The important factor is to look for science concepts that support students thinking. Answers
may reference the law of conservation of mass
which tells us that the inputs of a life cycle stage
will become products —wanted or unwanted—
so the disposal of the outputs need to be considered as well.
B-211
Issues and Physical Science • Student Sheet 29.1
2461 LabAids SEPUP IAPS TG
Figure: PhysTG B 29.02Trans
LegacySansMedium 10/11.5
12/14 Trans
Landfill waste
Old computer
Reclaim and recycle materials
such as metals, plastic, glass by
disassembling old computer
Materials made from
substances found in
natural resources
©2007 The Regents of the University of California
Computer is used
for entertainment
and/or work
Repair or upgrade
older or damaged
computer
Parts
manufactured
from materials
Computers are
packaged and shipped to
warehouses and stores
Computer
made by
assembling parts
Name
Date
Life Cycle of a Computer
B-213
Name
Date
Analyzing a Computer Proposal
Proposal Letter
Directions: List each of the features of this computer proposal
on a separate line. For each feature, explain in detail how it
affects the life cycle of a computer.
How it affects the life cycle of a computer
©2007 The Regents of the University of California
Proposal feature
Issues and Physical Science • Student Sheet 29.2
B-215
Name
Date
Comparing Computer Proposals
Computer
Proposal
Green Proposal Features
A
B
©2007 The Regents of the University of California
C
D
Issues and Physical Science • Student Sheet 29.3
B-217