Triple Science case study
Biology
Name of centre
Wadebridge School: a Business Enterprise College
Name of teacher
Mel Coombes
Subject
Biology
Specification
AQA
Brief description of case study
Students learn about making decisions about the environment in the context of biofuels.
Disclaimer
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Signed: Mel Coombes
Date: 20 October 2008
Page 1 of 9
Topic
Range and content
The use of ethanol-based biofuels
How Science Works
1.4 Applications and implications of science
Pupils should be taught:
a about the use of contemporary scientific and technological developments and their
benefits, drawbacks and risks
b to consider how and why decisions about science and technology are made, including
those that raise ethical issues, and about the social, economic and environmental effects
of such decisions
Extract from Key stage 4 programme of study: http://curriculum.qca.org.uk/key-stages-3-and4/subjects/science/keystage4/index.aspx
Context of the lesson within scheme of learning
Students have studied microbes and how these are used in industry. They have learnt
about biogas and now are moving on to biofuels. Within How Science Works, this lesson
encourages students to improve their skills at working critically with secondary evidence.
Learning objectives
•
Describe the uses of biofuels that are produced by the fermentation of plant material.
•
Use secondary data to make a justified decision about how technology should be
used.
•
Explain that scientific controversies can arise from interpreting data in different ways.
Learning outcomes
Students will be able to:
•
explain how biofuels can be produced by the fermentation of plant material
•
use secondary data to make a justified decision about how biofuels should be used
•
explain, using data, why scientists disagree about how useful biofuels are in slowing
climate change.
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Key concepts/knowledge/skills/understanding addressed by this lesson
The production and use of biofuels.
How evidence can be used to make decisions
Curriculum opportunities
a Research, experiment, discuss and develop arguments.
b Pursue an independent enquiry into an aspect of science of personal interest.
c Use real-life examples as a basis for finding out about science.
X
d Study science in local, national and global contexts, and appreciate the
connections between these.
e Experience science outside the school environment, including in the workplace,
where possible.
f Use creativity and innovation in science, and appreciate their importance in
enterprise.
X
g Recognise the importance of sustainability in scientific and technological
developments.
X
h Explore contemporary and historical scientific developments and how they
have been communicated.
Other curriculum opportunity from specification (give details):
Extract from Key stage 3 programme of study: http://curriculum.qca.org.uk/key-stages-3-and4/subjects/science/keystage3/index.aspx?return=/key-stages-3-and-4/subjects/science/index.aspx
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How Science Works progression in this lesson
The aspect of How Science Works being developed is:
• Developing explanations and understanding how the scientific community works
together
How are students making progress?
• Students will use evidence about biofuels to illustrate their understanding of how the
scientific community works together and how this can influence the acceptance or
rejection of a theory or idea.
Assessment opportunities in this lesson
Students will vote on their point of view through the lesson, and will justify their
decisions. This enables the teacher to see what the class are currently thinking, and also
gives individual accountability.
The new page for the textbook that is written in the subsequent lesson will be peerassessed.
How ICT is used to support learning
An Excel spreadsheet is used and a graph displayed that shows the number of votes
that support or disagree with the statement:
‘Hydrocarbon fuels should be replaced with biofuels because they are better for the
environment’.
As the lesson progresses, the students are able to see what the class as a whole thinks.
The graph changes over the course of the lesson as more evidence is discussed.
Overview of lesson
Lesson title: Biofuels – good or bad?
Approximate length of lesson: 60 minutes
Starter
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Students discuss and vote on the following statement:
‘Hydrocarbon fuels should be replaced with biofuels because they are better
for the environment’
Main
Introduce evidence and information about biofuels and take a series of class
votes during the lesson to see whether opinions change as more information
is revealed
1 Carbon-neutral biofuels
2 Carbon dioxide emissions from biofuels
3 Carbon dioxide, rising global temperatures and biofuels
4 The impact of biofuels on food prices and the environment
Plenary
Ask the students:
•
What happened in the lesson to make them change their minds?
•
How can we make sure we are making the right decisions about things
like this?
•
What should we do if decisions about science aren’t black and white?
Lesson in detail
Lesson title
Biofuels – good or bad?
Lesson structure
Learning
episode and
timing
Detail
Starter
(10 minutes)
Discuss the statement on a PowerPoint slide:
‘Hydrocarbon fuels should be replaced with biofuels because they
are better for the environment’.
Ask students to list the evidence they would need, or the questions
they would need to ask, to find out whether that statement was true
or not. Discuss in groups and then take feedback from the class.
Make a list of the questions on the board.
Ask students to vote on whether they agree with the statement.
Enter this into a spreadsheet.
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Main 1
(10 minutes)
Start to give out information about biofuels. The first piece of
information is that biofuels are claimed to be ‘carbon-neutral’. Ask
students to define what that means, and then ask them to explain
whether they think biofuels are carbon-neutral.
Ask students to vote again. Has anyone changed their view?
Main 2
(10 minutes)
Share the following data about carbon dioxide (CO2) emissions from
biofuels:
There are two main blends of biofuels used today. These two blends
are E10 (10% Ethanol and 90% Gasoline) and E85 (85% Ethanol
and 15% Gasoline). By looking at some data on emissions, it can
be concluded that the primary greenhouse gas, carbon dioxide, is
reduced by approximately 72% per kilometre through the usage of
E85 and by 7% per kilometre through the usage of E10, compared
to 100% gasoline.
(Kim and Dale 2006)
Ask students to vote again. Has anyone changed their view?
Main 3
(10 minutes)
Show students the graph that shows the level of CO2 and the global
temperature rising, available at
http://upload.wikimedia.org/wikipedia/commons/9/90/CO2Temp.png (see Resources).
In the light of this, are biofuels useful?
Main 4
(10 minutes)
Distribute the news articles about the impact of biofuels on food
prices and the environment (see Resources).
Take another vote on whether students agree with the statement
about the use of biofuels.
Plenary
(10 minutes)
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Ask the students:
• What happened in the lesson to make them change their minds?
• How can we make sure we are making the right decisions about
things like this?
• What should we do if decisions about science aren’t black and
white?
Reflection and evaluation
Starter
Discuss the statement:
‘Hydrocarbon fuels should be replaced with biofuels because they are better for the
environment.’
The students first needed to make sure that they all agreed what the terms in the
statement meant. So the class agreed what they meant by ‘better for the environment’,
but also agreed that this might have different meanings depending on how the terms
were defined.
When the students voted this time, they were mostly in agreement with the statement.
Main
Main 1: Carbon-neutral biofuels.
This section was interesting, as it revealed a number of misconceptions about
photosynthesis and provided an opportunity to revisit the photosynthesis equation. Many
students at first identified biofuels as carbon-neutral (ie the CO2 that they released on
burning was not a net gain to the atmosphere, because the plants used to produce the
fuels had originally taken the CO2 in from the atmosphere). Other students then pointed
out that energy was used to harvest and transport the crops – usually energy in the form
of fossil fuels. The general consensus was that, although biofuels might not be entirely
carbon-neutral, they were better than fossil fuels.
When the students voted again, a couple of students had changed their view because
they no longer agreed strongly with the statement.
Main 2: Carbon dioxide emissions from biofuels.
Students were impressed by the data here on the reduction in CO2 emissions by the use
of biofuels. They were also surprised that the ethanol was blended with petrol.
The number of votes for and against the statement did not change.
Main 3: Graph showing the level of CO2 and the global temperature rising. In the light of
this, are biofuels useful?
Some students immediately identified the graph as one they had seen before and took it
as further evidence that suggested they should support biofuels, as they were ‘better for
the environment’. Other students stated that the graph did not change their opinion
because biofuels might not just have an impact on carbon dioxide – there might be other
things to consider too.
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Main 4: The impact of biofuels on food prices and the environment.
The news articles I used here really caused some cognitive conflict for the students, as I
had intended. Some of the students who had felt strongly that biofuels were ‘better for the
environment’ found the idea that the plantations for biofuels were damaging the
environment difficult. Several students noted that they weren’t only damaging to the
environment, but that rising food prices were having an impact on human society,
particularly the poorest members of society.
The debate at this point became quite noisy so I split the class into groups of four to
discuss how this new information impacted on their response to the statement.
In the final vote, a number of students chose to disagree with the statement, which was a
big swing against the overall support for biofuels that existed at the start of the lesson.
Plenary
The students found the lesson difficult – particularly at the end, when their views were
being challenged and they felt that they had been given contradictory evidence. They felt
uncomfortable with the uncertainty that sometimes accompanies the decisions that have
to be made about science and new technologies.
Risk assessment
Not applicable.
Opportunities to take this further
Ask students to look at their science textbook at the page on biofuels. The information
there is likely to be out of date. Ask students to rewrite the page in the textbook in the
light of current knowledge about biofuels.
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Resources
Article about biofuels
www.guardian.co.uk/environment/2007/aug/17/climatechange.energy
Royal Society report on biofuels
http://royalsociety.org/document.asp?id=7366
Site discussing biofuels from the University of Michigan
http://sitemaker.umich.edu/section7group6/introduction
Kim, S, Dale, BE (2006). Ethanol Fuels: E10 or E85 – Life Cycle Perspectives.
International Journal of Life Cycle Assessment, 11(2), 117–121.
Graph of global temperature and atmospheric CO2
http://upload.wikimedia.org/wikipedia/commons/9/90/CO2-Temp.png
Impact of biofuels on environment and food prices
http://news.bbc.co.uk/2/hi/science/nature/6650743.stm
Impact of biofuels on food prices
www.guardian.co.uk/business/2007/jul/05/energy.environment
Bibliography
National Strategies Framework for Teaching Secondary Science: Overview and Learning
Objectives (2008) www.standards.dcsf.gov.uk/secondary/frameworks
Science Programme of Study for KS3 (Extract from National Curriculum) (QCA 2008)
http://curriculum.qca.org.uk/key-stages-3-and4/subjects/science/keystage3/index.aspx?return=/key-stages-3-and4/subjects/science/index.aspx
Science Programme of Study for KS4 (QCA 2008) http://curriculum.qca.org.uk/keystages-3-and-4/subjects/science/keystage4/index.aspx
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