Senior Form Chemistry
– How do scientists do science?
How do scientists do science?
Teacher’s Version (with video exemplars)
1.
2.
3.
4.
5.
6.
7.
8.
NOS/STSE Features
Scientists publish their work. The quality of the
publications is often safeguarded by peer review.
Peer review aims to be objective but social or
personal values may sometimes affect scientific
judgement.
Scientists should not submit to authority.
Experimental and non-experimental studies are
both valuable in science.
All cultures can contribute to science.
Collaboration is common in science.
Both females and males can contribute to science.
Most scientific research is multi-disciplinary.
You can click an icon like this
to access the activities in this package.
You can click an icon like this
to access the PowerPoint files in this package.
You can click an icon like this
to access the exemplar videos in this package.
If the links do not
work, try again by
pressing the “Ctrl”
key and clicking
the icon at the same
time.
Table of Contents
Introduction
(i)
Activity 1: How do scientists tell other scientists what they are doing?
P.1
Activity 2: Is vitamin C a cure for colds?
P.8
Activity 3: Are experiments the only way to develop scientific
knowledge?
P.11
Extension activity: Investigations about vitamin C
P.14
Appendix 1: A list of papers for the extension activity
P.18
Appendix 2: Lesson Plan
P.19
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Introduction
Rationale
“How is scientific knowledge established?” is a question not addressed by many
science textbooks. In this set of materials, students have the chance to experience the
process of reviewing and evaluating scientific papers. How scientists solve some
problems in research will be investigated by looking into some studies on vitamin C.
This package also emphasizes the value of non-experimental research in science.
Students will be able to analyze the benefits and drawbacks of experimental and
non-experimental approaches to research. This will broaden their scope when they
design scientific investigations.
Level of study
Number of lessons
Form 6
4 lessons (each lesson 35-40 minutes)
Contents
1. Peer review among scientists
2. Evaluating scientific study
3. The use of experimental and non-experimental approaches to investigation in
science
4. Myths about science and scientists
Teaching package includes
1. Worksheets (Teacher’s Version and Student’s Version)
2. A Teaching PowerPoint
(i)
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Activity 1
How do scientists tell other scientists what they are
doing?
Hello! Oh, Sorry! I have got a cold! My mum just told me to take
some vitamin C to get rid of the ……..!!! I never heard of that!
Let me search for information concerning vitamin C. Hey! I have
found a famous person who believed vitamin C can cure colds.
Below are the notes I jotted down…
Notes: The PowerPoint contains a more detailed description of Linus Pauling.
Teacher may ask students to discover more about the life of Linus Pauling.
Linus Pauling
 He systematically developed our understanding about chemical bonding.
His work not only influenced modern research in chemistry but also
molecular biology.
 He was competing with the competition with Watson & Crick to discover
DNA structure in 1950s.



He is one of the few people who have been awarded two Nobel Prizes: one
in Chemistry (1954) and one for Peace (1962)
He believed that taking a high dose of vitamin C regularly could prevent
colds
He wrote a book Vitamin C and the Common Cold in 1970

Q1 Was Linus Pauling a chemist or a biologist?
He was both a chemist and a biochemist. (He worked across disciplines.)
Homework (Optional): Look for more information about Linus Pauling! Why was Pauling
given the Nobel Peace Prize in 1962? What does this tell you about the participation of
scientists in society?
Scientists also participate actively in society. They may join social campaigns or be active in
affecting political decisions.
Reference:
Nobel Prize official website: http://nobelprize.org/ (Last visited: 1/6/2006)
Biography of Linus Pauling: http://nobelprize.org/peace/laureates/1962/pauling-bio.html (Last
visited: 1/6/2006) (English version only)
P. 1
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Look at the cartoon showing the conversation between two scientists and discuss the
questions with your classmates.
I am finding if there is any
research about the effect of
vitamin C on the common
cold.
What are you doing?
S
Didn’t Linus
Pauling write a
book claiming that
vitamin C can treat
colds?
c
i
pa
pe
rs
e
Yes. But his claim is not
yet accepted by most
scientists.
Results must be reviewed by other
scientists. Oh! I’ve found them. There are
lots of studies investigating his idea.
n
cWhy?
e
Q1 Why do scientists have to spend time searching out and reading other scientists’ work?
They can avoid repeating the work that was done by other scientists.
They can base their own ideas on the work of others and also develop others’ work.
Scientists publish their work. This is one way that
scientific knowledge is disseminated.
Q2 Why have scientists conducted so many studies about the effects of vitamin C rather than
simply believing in what Pauling said?
Although Pauling was a renowned figure, his idea was not consistent with what other scientists
had shown. People might not believe that vitamin C can treat the common cold.
In order that Pauling’s idea may be accepted, extensive investigations have to be conducted to
demonstrate the effectiveness of vitamin C.
Notes: Students will take the role of scientists / journal reviewers to evaluate the quality of
scientific papers in next part.
Scientists do not believe any statement made by other
scientists without strong evidence.
P. 2
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
As stated in the cartoon, scientists have to publish their
work in print or on the internet, in “scientific journals” to
let other scientists know about their results. There are
thousands of scientific journals in the world. You can find
some in the public libraries.
When a scientist submits a study to a particular journal the work will be
reviewed by the editorial board. The board is composed of a group of
scientists. They will review the quality of the papers and determine
whether the papers are good enough to be published.
Additional information: In an editorial board, there is a chief editor who will receive
manuscripts from scientists. The board meets to decide which manuscripts might be suitable for
publication. Then each one is sent to a number of reviewers for further comment before making
a final decision.
The job of a reviewer (who is an expert in the field of the study) is to evaluate the quality
of a scientific paper. Factors such as (i) the significance and originality of the research (ii)
the validity of the investigation (iii) the trustworthiness of the results and findings (iv)
the quality of the writing and overall presentation will be considered. A significant piece
of research may open up new directions or areas for further investigation. A reviewer
will not repeat the research to check reliability. They will use their professional
knowledge to judge whether the paper is worthy of publication.
Notes: The reading of the manuscripts can be assigned as homework while the discussion should
take place in the class. This activity is also suitable for Form 6 students for report writing.
Instead of using the manuscripts given, students may comment on their own reports.
Remarks: Students are expected to experience the review process with emphasis on the nature of
science:
1.
The fame of the institution might bias the process of review (Therefore, in the activity, the
names and institutions of the authors are removed before the review process.)
2.
Conflict of interest of reviewers (Reviewer 4 in this activity) might bias their decision. But
the peer review system tries to minimize this effect and guards fairness.
Peer review aims to be objective but social or personal values may sometimes
affect scientific judgement.
P. 3
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Let’s try the reviewing process! Divide into groups of four. Each of you will be a
reviewer of the Journal of Nutrition. Choose your role first!
Remarks: The papers are on p.7 and 8.
Reviewer 1 (Dr. Kelvin King)
You are Dr. Kelvin King, a senior scientist at The China Nutrition Institute, also a reviewer for
the Journal of Nutrition. You have just received two papers from the chief editor. Every
journal has limited space. You have to decide which paper can be published in the journal.
You may also reject both papers.
Reviewer 2 (Dr. Louise Lee)
You are Dr. Louise Lee, a senior scientist at The University of Hong Kong, and a reviewer for
the Journal of Nutrition. You have just received two papers from the chief editor. Every
journal has limited space. You have to decide which paper can be published in the journal.
You may also reject both papers.
Reviewer 3 (Dr. Mary Wong)
You are Dr. Mary Wong, a senior scientist at England University, also a reviewer for the
Journal of Nutrition. You have just received two papers from the chief editor. Every journal
has limited space. You have to decide which paper can be published in the journal. You may
also reject both papers.
Reviewer 4 (Dr. John Talaka)
You are Dr. John Talaka, a senior scientist at The University of Paris, also a reviewer for the
Journal of Nutrition. You have just received two papers from the chief editor. Every journal
has limited space. You have to decide which paper can be published in the journal. You may
also reject both papers.
After you have received the papers, you find that the study is very similar to the research that
you have been doing. You are also about to publish your results. If you allow the paper you
are reviewing to be published before yours, the impact of your study will become less
significant. In the science community, those who publish new finding will gain more credit.
P. 4
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Justify your decision in the following boxes.
Manuscript 1
Accept / reject (Please circle your decision)
Reasons:
Reviewers work independently.
Don’t discuss with each other
before you have made your own
decision.
Manuscript 2
Accept / reject (Please circle your decision)
Reasons:
Vote for the papers! Which paper did your group accept, or did your group reject both?
Now summarize the reasons for the group’s decision and present them to classmates.
A comparison of the manuscripts:
Manuscript 1 (M1)
Manuscript 2 (M2)
Materials and 1g of vit C powder is
1g of vit C powder is
methods
dissolved in 200ml water dissolved in 500ml
water
20oC, 40 oC…
25oC, 40 oC…
Solutions were kept at
Solutions were kept at
constant temperature for constant temperature
30 minutes.
for 15 minutes.
Experiment was repeated Experiment was done in
until consistent results
triplicate.
were obtained. 
Results and No description on the use It described the
discussion of statistical analysis
program used in
program.
statistical analysis.
Comment
The differences are unlikely
to affect the result.
The effect of heating on
vitamin C might be better
shown by M1.
The method in M1 ensured
more reliable results.
More details were given in
M2. But the difference in the
choice of statistical program
might not affect the results.
(It is the method of analysis
which might affect the
results.)
Summary It stated that food
It described other
The summary of M1 was not
processing would not
factors that may affect supported by its results. For
affect vitamin C content. the stability of vitamin M2, it opened new areas for
C. 
further studies.
Remarks: Teachers may develop the consequences of rejection further if students seem
interested.
P. 5
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Manuscript 1
Vitamin C is not destroyed by heat
Notes: Name of authors and institutes are removed for the review process.
Introduction
Vitamin C is believed to be lost during cooking. People always believed that we could not
take in enough vitamin C from cooked food. The purpose of the study is to investigate
whether heat can destroy vitamin C.
Materials and Methods
Vitamin C powder was purchased from ChemTech Ltd. A solution was prepared by dissolving
1 g of powder into 200 ml distilled water. 10 ml of vitamin C solution was kept at 20℃, 40℃,
60℃ , 80℃ or 100℃ for 30 minutes. The vitamin C content was then measured by titrating
the vitamin C solution against 1 ml DCPIP solution. The experiment was repeated until
consistent results were obtained.
Results and Discussion
The results are illustrated in the diagram below. There was no significant difference in
Amount of vitamin C
used in titration / ml
vitamin C content remaining after treatment at different temperatures.
3000
2500
2000
1500
1000
500
0
The graph shows the vitamin C
content of the solutions in different
temperature. The error bar shows
the standard deviation of each trial.
20
40
60
80
100
Temperature / C
o
Summary
The results indicated that heat did not destroy vitamin C. Thus, food processing will not affect
the vitamin C content of a particular food.
P. 6
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Manuscript 2
Vitamin C Destruction during Heating
Notes: Name of authors and institutes are removed for the review process.
Introduction
Vitamin C is a vital substance for health. Heating is believed to destroy vitamin C thus
lowering the vitamin C content in food during cooking. The purpose of this experiment was to
determine whether increasing temperatures decompose Vitamin C.
Materials and Methods
Vitamin C solution was obtained by dissolving 1g of vitamin C in 500 ml distilled water
(vitamin C tablets were purchased from BioChem Technology Ltd.). For each temperature, 50
ml of vitamin C solution was used. The solutions were heated to 40℃, 60℃ 80℃ or 100℃
and maintained at a constant temperature for 15 minutes. A control solution was maintained at
room temperature (25℃).
After 15 minutes, vitamin C concentration was measured by titrating the vitamin C solution
against 1 ml DCPIP solution. The amount of vitamin C solution used was recorded. The
procedure was repeated three times at each temperature.
Amount of vitamin C used in
titration (ml)
Results and Discussion
The correlation between temperature and vitamin C concentration was determined using the
Statistical Analysis Computer Program version 1.0. There was no significant difference in
vitamin C content at different temperatures. The results are shown in fig.1.
0.3
0.25
0.2
0.15
Fig. 1. The graph shows the amount
of vitamin C used for the titrating
the DCPIP. The error bars show the
standard deviation in each trial.
0.1
0.05
0
25
40
60
80
100
o
Temperature ( C)
Summary
Vitamin C is not destroyed by heating. This is especially important for the food processing
industries. However, other factors such as oxidation and the decomposition of vitamin C in
different solutions (e.g. salt solution), which have not been considered in this study, may also
affect the availability of this micronutrient to consumers. Further study is needed.
P. 7
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Activity 2
Is vitamin C a cure for colds?
Unlike humans, most mammals are able to synthesize their own vitamin C. They are able to
produce vitamin C from glucose in the following steps:
W
X
Y
Z
Glucose Enzyme

 Chemical A Enzyme


 Chemical B Enzyme


 ChemicalC Enzyme


 Ascorbic Acid
Most of the above biochemical pathway also happens in our body. However, our body does
not have Enzyme Z. As a result, when glucose has been converted to chemical C, the reaction
stops and humans cannot synthesize vitamin C. We need it from our diet.
It has been found that when some animals are sick, the amount of
vitamin C in their body will increase tremendously. Therefore, Linus
Pauling suggested that the missing enzyme is due to a genetic
deficiency in our evolution and that when we are sick, we would, like
other mammals, need more vitamin C.
Pauling caused controversy about using vitamin C for treating or preventing disease. His
hypothesis is not easy to prove or disprove, but he has triggered extensive research on the use
of vitamin C for the treatment of colds. This famous experiment was conducted by Karlowski
and his colleagues in 1975. Details are on the next page:
Remarks: This is the pathway by which glucose is converted to ascorbic acid in mammals.
Source: Le Couteur, P. & Burreson, J. (2003) Napoleon's buttons: how 17 molecules changed
history. New York: J.P. Tarcher/Putnam, pp.46-47
P. 8
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Notes: Teachers might like to ask students to devise a plan to test the hypotheses.
Aims:
To determine whether taking vitamin C can prevent or cure colds.
Hypothesis:
1. Taking high doses of vitamin C helps prevent colds
2.
Taking high doses of vitamin C at the first signs of a cold reduces its length and
severity
Remarks: The use of a placebo is explained in the PowerPoint.
Methods:
To investigate whether vitamin C can prevent colds, all subjects were asked either to take
the ‘maintenance capsules’ containing vitamin C or a placebo (安慰劑) daily (see table
below).This tests for hypothesis 1. Meanwhile, to test the second hypothesis, when they
felt the symptoms of a cold developing, they were asked to see the researchers and get a
supplementary capsule – which contained either vitamin C or the placebo – within 12
hours. When the cold was over, the subjects were asked to report the duration and severity
of the symptoms to the researchers.
311 subjects volunteered for the experiment. They were randomly assigned to four groups
as summarized in the table below. They did not know which group they belonged to.
Group
Maintenance capsule
Supplementary capsule
1
Placebo
Placebo
2
Placebo
3 g Vitamin C
3
3 g Vitamin C
Placebo
4
3 g Vitamin C
3 g Vitamin C
(N.B. A placebo is given to subjects in the control groups so that no subject can guess
whether or not they receive treatment. In this study, the placebos contained lactose.)
Notes: Vitamin C tablets and lactose (glucose can be used instead of lactose) must be given to
students to taste. This can guide students to answer the questions on the next page.
P. 9
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Q1 Can you find any problems in the experimental design? What are they?
-
Some participants tasted the capsule and identified which group they belonged to. There
would be some psychological effects on participants that might affect the results.
-
It is the subjects themselves who (i) reported the number of colds and (ii) decided whether
they had caught a cold. Their decisions could be very subjective and may vary from person
to person.
Q2 If you were the researchers, what would you do when you discover the same problem?
(Notes: Students should be encouraged to give their own opinion)
Q3 After this study, scientists have continued to argue about the effect of vitamin C in curing
the common cold. Why? (Note: Pauling recommended 6 g to 18 g vitamin C daily.)
In Karlowski’s study, the dosage of vitamin C used may not have been high enough to prevent or
cure colds.
Q4 What can you observe about the attitude of scientists and the nature of science from this
study of vitamin C?
Scientists criticize each other’s work.
Scientists are flexible in how they work. (See PowerPoint) They often re-evaluate and modify
their methods in order to answer their questions.
They do not strictly follow a planned way of doing research.
Scientific knowledge is sometimes inconclusive.
P. 10
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Activity 3
Are experiments essential in developing scientific
knowledge?
The study in Activity 2 is called an experiment. In your view, what is an experiment?
(Students can brainstorm what they have learnt about experiments.)
An experiment is a test conducted in controlled situation to verify a hypothesis.
Only one factor can be tested in each experimental procedure. All other variables should be kept
constant. A control is usually set up which differs only in the test factor, to rule out the influence
of other factors.
This is a brief summary of a piece of research reported in Japan in the year 2000.
The study was started in 1977 in a Japanese rural community. The researchers invited a
group of 880 men and 1241 women aged 40 years for investigation. These people were
followed by researchers for the subsequent 20 years. During the period, the researchers
recorded the number of strokes (中風) occurring in the sample. Meanwhile, the vitamin
C level in their blood and their diet were also recorded.
At the end of the study, there were 196 incidents of stroke. The number of strokes was
inversely related to the blood vitamin C level (i.e. the chance of getting a stroke was
lower in a person who had a high vitamin C level.)
Source: Yokoyama et al. (2000) Serum vitamin C concentration was inversely associated
with subsequent 20-year incidence of stroke in a Japanese rural community: The Shibata
study. Stroke 31: 2287-2294
Q1 Comment on whether or not this study is an experiment, give your reasons.
No. There is neither a treatment group nor a control group. The variables are not
controlled in the study. The researchers only generalize the relationship between
vitamin C level and the chance of suffering a stroke in a population.
(Notes: This kind of study is known as a prospective study. It is an observational study in which
a group of people are tested for risk factors (e.g. nutrition), and then followed up at subsequent
times to determine their status with respect to a health outcome.)
P. 11
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Q2 Suggest why the researchers use such approach for the investigation?
The researchers (1) cannot control the diet of people or their blood vitamin C level for 20
years, (2) cannot control all other factors that may affect the chance of suffering a stroke such
as smoking, doing exercise, genetic makeup of the subjects, etc. The researchers can
only deduce the relationship between the blood vitamin C level and the chance of
getting strokes from a sample of population.
Experimental or non-experimental method, which one is better?
You are a group of scientists who are planning some medical
investigations. Decide whether you will use an experimental or
non-experimental approach. You have to prepare a 5-minute
presentation (i) to explain the aim of your study and (ii) to justify
your approach to the investigation.
Notes: Divide students into groups with each group responsible for one case. The suggested
solutions are only possible answers. Students are encouraged to work out their own research
methods.
Case 1
The harmful effects of passive smoking on foetuses have raised concern in recent years. You
and your colleagues want to know whether passive smoking may cause miscarriage (natural
abortion).
Is it possible to use an experimental approach in this case?
It is unethical to use an experimental approach. A possible method is to recruit pregnant
women volunteers to participate in the study. A survey can be used to check whether the
volunteers are subjected to passive smoking at home or in the workplace and the status of
their growing foetuses is recorded regularly by researchers.
Also many natural abortions
occur even before a woman knows she is pregnant, this may affect the outcome.
Case 2
A new drug has been produced for the treatment of HIV/AIDS. If the drug is effective, it
will save millions of lives. You have to investigate the effect of the new drug for treating
HIV/AIDS.
How can the effectiveness of the drug be determined?
An experimental approach may be used. Volunteer patients are divided into two groups: one
P. 12
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
group receives the new drug while the control group receives a placebo. The symptoms of HIV/
AIDS infection are recorded so as to determine the effectiveness of the drug.
Case 3
You suspect that a chemical present in a certain species of fish causes diarrhoea. If it is
really the case, there will be a dramatic decrease in cases of diarrhoea just by asking people
not to eat that species of fish.
How can you gather information to support your hypothesis?
It is unethical to test the chemical on human. But scientists can collect indirect evidence to
support the hypothesis. The structure of the chemical can be investigated to see whether there
are potential diarrhoea-causing properties. A survey can be done to see whether there is direct
correlation between the consumption of the fish species and diarrhoea. Furthermore, an
animal test can be carried out to test whether the chemical causes diarrhoea in animals. (This
animal test may also have ethical concerns.)
After your presentation, summarize the benefits and drawbacks of different approaches in the
table below.
Notes: Students should be encouraged to give their own answers.
The pros and cons of using experimental and non-experimental approaches
Experimental approach
Benefits
 It is more likely to rule out other
factors which may affect the
results.
Drawbacks
Non-experimental approach
 Little ethical consideration.
 More suitable for long-term
studies such as nutrition research
 Not ethical when the trial may put
the subject at risk (e.g. the long
term effect of using mobile phone
 Difficult to control different
variables.
 The researchers may not be able
or doing LASIK; finding the cause
to take charge of the number of
of diseases).
subjects.
 It is not very helpful in the
discovery of new planets or new
biological species on Earth.
Are experiments essential in developing scientific knowledge?
P. 13
No.
Experiments are not the only way to do science.
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Extension activity: Investigations about vitamin C
Here are some typical images of science and scientists that people have.
(4) Scientists work
in universities.
(1) Science is done
in western
countries.
(5) Science is done
only within a subject
discipline.
(2) Scientists work
alone.
(3) Scientists are
male.
Notes: Teacher may guide students to get information from the extracts by using PowerPoint
slide 38. The extracts are from real papers but the titles are modified for secondary school
students.
There are thousands of studies concerning various aspect of vitamin C. The next page
shows extracts of some real scientific papers about vitamin C. Find out whether the
images above are accurate or not. Do your observations of the papers agree with the
images of scientists /science suggested in the media?
1.
2.
3.
4.
All cultures can contribute to science.
Scientists often collaborate.
Both females and males can contribute to science.
Most scientific research is multi-disciplinary.
Notes: Some guiding questions:
(1) What countries do these pieces of research come from?
(2) Other than universities, what other organizations have taken part in the research?
(3) Which papers give you the idea that scientists work across disciplines?
(4) Look at papers 1 and 6, how do they demonstrate that scientists build on others’ work?
Remarks: The titles of the papers are simplified. A list of the papers is presented in Appendix 1.
P. 14
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
1.
2.
P. 15
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
3.
4.
5.
P. 16
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
6.
7.
8.
P. 17
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Appendix 1: A list of papers for extension activity
1. Pe´rez, A. G., Olı´as, R., Espada, J., Olı´as, J. M. and Sanz, C. (1997) Rapid
Determination of Sugars, Nonvolatile Acids, and Ascorbic Acid in Strawberry and
Other Fruits. Journal of Agriculture and Food Chemistry 45: 3545-3549
2. Del Caro, A., Piga, A., Pinna, I., Fenu, P. A. and Agabbio, M. (2004)Effect of Drying
Conditions and Storage Period on Polyphenolic Content, Antioxidant Capacity, and
Ascorbic Acid of Prunes. Journal of Agriculture and Food Chemistry 52: 4780-4784
3. Block, G. (2002) Ascorbic Acid, Blood Pressure, and the American Diet. Annuals of
New York Academy of Science 959: 180-187
4. Han, J. S., Kozukue, N., Young, K. S., Lee, K. R. and Friedman, M. (2004)
Distribution of Ascorbic Acid in Potato Tubers and in Home-Processed and
Commercial Potato Foods. Journal of Agriculture and Food Chemistry52: 6516-6521
5. Xu, J. and Jordan, R. B. (1990) Kinetics and Mechanism of the Reaction of Aqueous
Iron(Ii1) with Ascorbic Acid. Inorganic Chemistry 29: 4180-4184
6. Carr, R. S., Bally, M. B., Thomas, P. and Neff, J. M. (1983) Comparison of Methods
for Determination of Ascorbic Acid in Animal Tissues. Analytical Chemistry 55,
1229-1232
7. Yuan, J. P. and Chen, F. (1998) Degradation of Ascorbic Acid in Aqueous Solution.
Journal of Agriculture and Food Chemistry 46: 5078-5082
8. Harel, S. (1994) Oxidation of Ascorbic Acid and Metal Ions As Affected by NaCl.
Journal of Agriculture and Food Chemistry 42: 2402-2406
P. 18
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Appendix 2: Lesson Plan
Activity 1: How scientists publish their work?
Time
35 min
Intended Learning Outcomes
Students should be able to state and
appreciate that

scientists spend a lot of time to read
others’ work;

scientific findings are reported to other
scientists;

scientists aim to be objective;

a peer review system can provide a
comparatively fair judgment of a
finding.
Teaching Flow
Teacher may ask students how they prevent and treat common 
colds.

Students read the story of Linus Pauling and discuss which

disciplines of science Pauling belonged to.
Homework:

Students can search for more information about Linus Pauling
at home and discuss the participation of scientists in the society.









P. 19
Materials

Students read the cartoon and discuss the reasons for scientists
to read others’ work and to publish their work.
Teacher shows some famous scientific journals to students.
Students read the process of peer review and the job of
reviewers.
Students divided into groups of four. Each student represents a
reviewer in the journal.
Students read their task sheet and the two manuscripts.
Students make an individual decision on the publication of the
manuscript.
Students in each group vote for the papers their group has.
Students present their reasons for accepting and rejecting
papers.
Teacher could emphasize that a peer review has provided a
comparatively fair judgment of a finding and science aims to be
objective.
Activity 1
worksheet
PowerPoint Slide
2 - 18
Remarks
Teacher can ask students
to find information about
Linus Pauling before the
lesson.
Teacher can show how to
search for journals in
public libraries.
In reality, the process of
publishing scientific
findings is more
complicated. It is
simplified in this package
as the aim of the package
is to raise students’
awareness on the peer
review system and the
objectiveness of science
but not the publication
process itself.
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Activity 2: Is vitamin C a cure for colds?
Time
Intended Learning Outcomes
Students should be able to

criticize scientists’ work;

point out the attitude of scientists in
doing research.
Teaching Flow





35 min



P. 20
Materials
Students read / Teacher delivers the basis of Linus Pauling
proposition (Worksheet p.9).
Teacher may ask students to devise a plan to test whether
vitamin C can cure colds.
Teacher introduces the Karlowski experiment.
Students brainstorm the problems in the experimental design.
Students discuss the methods in investigating the problems
found.
Students read the results done by Karlowski et al.
Students discuss the attitude of scientists in the study.
Students discuss the reasons for disagreement on the
colds-curing effect of vitamin C.



Remarks
Vitamin C tablets and
Activity 2
glucose (used instead of
worksheet
PowerPoint Slide lactose) to students to
taste.
19-29
Vitamin C tablets
and glucose
Vitamin C tablets (500
mg) can be obtained
from local stores (e.g.
Mannings, Watsons).
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Activity 3: Are experiments essential in developing scientific knowledge?
Time
Intended Learning Outcomes
Students should be able to

Be aware that experiment is not the
only method in developing scientific
knowledge;

state the benefits and drawbacks of
experimental and non-experimental
approaches in science.
35 min
Teaching Flow








P. 21
Materials
Students discuss their ideas about what experiment is.
Students read the study in Japan.
Students discuss whether the study is an experiment.
Students discuss the limitation of experiment in this kind of
study.
Students discuss the factors affecting the results of the study.


Remarks
Activity 3
worksheet
PowerPoint Slide
30-35
Students divided into groups, each discuss the investigation
method of a study.
Students present their choice of method in investigation.
Students discuss the benefits and drawbacks of experimental
and non-experimental approach in scientific studies.
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved
Senior Form Chemistry
– How do scientists do science?
Extension activity: Investigations about vitamin C
Time
35 min
P. 22
Intended Learning Outcomes
Students should be able to state and

appreciate that

all cultures and both male and female 
contribute to science;

collaboration among scientists is very 
common;

most scientific research is
multi-disciplinary, and that research on
Vitamin C is still undergoing across
disciplines.

Teaching Flow
Materials
Students discuss some common myths of science shown on

worksheet.
Teacher shows an extract from a paper and tells students how to 
get information about the authors, organization from the paper.
Students find evidence from the extracts to dispel the typical
myths of science.
Remarks
Extension activity
worksheet
PowerPoint Slide
36-43
© 2007 The University of Hong Kong – Faculty of Education. All rights reserved