2019 Science Extension Sample Paper

NSW Education Standards Authority

HIGHER SCHOOL CERTIFICATE EXAMINATION

SampleQuestions

Science Extension

• Readingtime–10minutes• Workingtime–2hours• NESAapprovedcalculatorsmaybeused• Headphonesaretobeused

Section I – 20 marks(pages3–4)• AttemptQuestions1–xx• Allowabout45minutesforthissection

Section II – 30 marks(pages5–9)Thissectionhastwoparts,PartAandPartBPartA–15marks• AttemptQuestionsxx–xxPartB–15marks• AttemptQuestionxx• Allowabout1hour15minutesforthissection

General Instructions

Total marks: 50

This document is NOT a complete sample examination. It provides some sample questions for the two sections of the examination. The questions will be formatted for a computer-based examination.

This cover page illustrates the examination specifications for a complete Science Extension examination.

The first HSC examination for the new Science Extension Stage 6 syllabus will be held in 2019.

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The first HSC examination for the new Science Extension Stage 6 syllabus will be held in 2019.

The Science Extension examination specifications can be found in the Assessment and Reporting in Science Extension Stage 6 document.

Questions may require candidates to integrate knowledge, understanding and skills developed through studying the course.

The examination will be undertaken by students using a computer. Prior to the commencement of the HSC written examination period, schools will be required to upload each student’s Scientific Research Report so that students may refer to their report if required, in responding to questions during the examination.

There is no expectation that all of the Year 12 content will be examined each year. The examination will test a representative sample of Year 12 content in any given year.

The following sample questions provide examples of some questions that may be found in HSC examinations for Science Extension. Each question has been mapped to show how the sample question relates to syllabus outcomes and content. The marking guidelines indicate the criteria associated with each mark or mark range.

The sample questions, annotations and marking guidelines provide teachers and students with guidance as to the types of questions to expect and how they may be marked. They are not meant to be prescriptive. Each year the structure of the examination may differ in the number and type of questions, or focus on different syllabus outcomes and content.

Note:

• Commentsincolouredboxesareannotationsforthepurposeofprovidingguidanceforfuture examinations.

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Section I

20 marksAttempt Questions 1–xxAllow about 45 minutes for this section

Question 1 (6 marks)

Concrete can be treated to vary its strength for particular purposes. A team of scientists conducted an experiment with two treatments to determine whether either could be used to strengthen concrete to the minimum requirement of 22 MPa for footpaths.

In the experiment, two identical concrete mixtures were treated, one with Treatment 1 and the other with Treatment 2. Each of the treated mixtures was used to construct thirty cylinders that met industry standards. The cylinders were tested and measurements of concrete strength in MPa were taken.

The scientists compared the mean strengths of the two treated concrete mixtures using a t-test. First, they checked the assumptions and then they conducted a two-sample t-test with a significance level of p < 0.001. The t-test analysis is shown.

Treatment 1 Treatment 2

Mean 21.93 23.40

Standard deviation 0.31 0.28

Null Hypothesis: Mean Difference = 0

Alternative Hypothesis: Mean Difference ≠ 0

t Stat: 19.48

P(T < = t) two-tail: 4.00 × 10–27

t Critical two-tail: 3.45

What conclusions can be drawn about the relative strengths of the two types of treated concrete and the suitability of each for the intended purpose? Justify your answer.

This is NOT a complete sample examination. Two sample questions are included in this section.

Questions may require interpretation of the results of statistical analyses. They will not require students to carry out the statistical test(s).

Items in this section may have a range of values up to and including 7. In these sample questions the item value is 6.

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It is thought that Australian fur seals lower their heart rate during a dive under water. A dive is defined as the total time the seal spends submerged under water. Dives can last for up to 20 minutes. A lower heart rate may assist seals to conserve oxygen while under water and therefore extend dive time. Resting heart rate when seals are above water is 100 beats per minute (bpm). Devices that record a range of variables, including heart rate, can be attached to seal skin. The devices can send data back to researchers. A researcher wants to investigate the following two questions:

i) Does the heart rate of Australian fur seals change when they dive under water?

ii) Are the dive times of Australian fur seals extended by having a lowered heart rate under water?

Construct a plan for an investigation that could be used to test these questions. In your response, include a plan for analysis.

This is an example of a question that requires students to use the Working Scientifically outcomes in planning investigations, including the method(s) of data collection, expected types of data and the relevant statistical tests used to verify the significance of results obtained.

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Section IIAllow about 1 hour and 15 minutes for this section

Part A – 15 marksAttempt Questions xx–xx


Read the following stimulus and answer the questions below.

Inhaling from an isopropanol pad may be a good cure for nausea

Millions of people suffer from nausea and vomiting yearly. Sufferers who attend hospital for treatment are often provided with the oral drug Zofran. Inhaling isopropanol is also known to assist in reducing nausea.

In a study, researchers investigated the use of isopropanol in hospital emergency rooms. 122 patients were selected from those presenting with nausea and assigned randomly to the following treatments:

• 40treatedwithsmellinganisopropanolpadandtakingoralZofran

• 41treatedwithsmellinganisopropanolpadandtakinganoralplacebo

• 41treatedwithsmellingasalinesolutionpadandtakingoralZofran.

Note: a placebo is a substance that has no medicinal effect on the human body. Patients are not told whether they have been given the placebo or not.

Question 3 continues on page 6

This section has two parts, Part A and Part B.

This is NOT a complete sample examination. Three sample questions are included in this section.

Questions in this section may contain one or more pieces of extended stimulus material in a range of forms such as journal articles, audio and video. However, stimulus material will only be included when it is essential for answering the question.

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Question 3 (continued)

The severity of nausea is measured on a scale based on observation, with 0 (zero) being no observed nausea and 100 being the worst. The researchers used established protocols for measuring nausea severity. The results after half an hour of each treatment appear below:

Isopropanol and Zofran

Isopropanol and placebo

Saline and Zofran

Severity of nausea symptomsobserved on 0–100 scale

Average nausea severity

0 20 40 60 80 100

Before treatment

After treatment

Data adapted from the Annals of Emergency Medicine, Vol. 72, No.2, Michael D. April, MD, DPhil; Joshua J. Oliver, MD; William T. Davis, MD; David Ong, MD; Erica M. Simon, DO,

MHA; Patrick C. Ng, MD and Curtis J. Hunter, MD. Aromatherapy Versus Oral Ondansetron for Antiemetic Therapy among Adult Emergency Department Patients: A Randomized Controlled

Trial, Page 184, © 2018, with permission from Elsevier.

(a) Justify the ethical protocols that should be considered in planning and conducting this study.

(b) Develop a research question and an appropriate conclusion for this study. Justify your conclusion.

(c) Evaluate the validity of this study. In your answer suggest ways that the study could be improved.

End of Question 3

5

4

6

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In this question TWO sources are provided that examine the use of fuel created during waste plastic pyrolysis as an alternative to diesel fuel. Pyrolysis is the process of decomposing materials using high temperatures in an inert atmosphere.

Source 1 is a summary of a student report and Source 2 is a video.

Refer to these TWO sources in your response.

Source 1

Waste Plastic Pyrolysis Fuels versus Conventional Diesel Fuel

Plastic pollution and energy shortages are pressing issues in today’s world. Waste plastic pyrolysis attempts to solve these problems by eliminating waste from the environment while creating a viable alternative fuel to replace conventional fuels. This research examined whether waste plastic pyrolysis fuels are similar to conventional diesel and, thus, a plausible alternative fuel. We created three distinct waste plastic pyrolysis fuels.

We conducted tests on each of the three waste plastic pyrolysis fuels and the same tests on diesel fuel. We tested the efficiency of each fuel, how much energy it produced, and how long it burned.

Overall, we found that diesel fuel burns much longer than all other tested fuels. This fact, combined with its high calorific (energy) value and efficiency scores, suggests that among those tested, diesel is the highest-quality fuel. Our results differ from other published research, which found that waste plastic pyrolysis fuels mixed with diesel performed similarly to pure diesel. The researchers tested these fuels for fuel efficiency and thermal energy production. Their results supported the equality of alternative fuels to diesel and were also consistent with several other pieces of published research that we have read. Our research was limited in comparison to other published research in this area, as we did not have access to very advanced materials and technology.

Another consideration in this area of research is whether waste plastic pyrolysis fuels result in a net gain of energy. Alternative fuels such as those described in this experiment take a large input of energy to create, so this requirement must be weighed against the energy output these alternative fuels can provide and could be a potential drawback to their use.

Adapted from:Differentiation of Waste Plastic Pyrolysis Fuels to Conventional Diesel Fuel,

Zachary Jewison (1), owen rokita (1), Joe rasmus (1) (1) Williamston High School, Williamston, MI May 25, 2018

https://www.emerginginvestigators.org/articles/differentiation-of-waste-plastic-pyrolysis-fuels-to-conventional-diesel-fuel

Question 4 continues on page 8

This is an example of a question with more than one stimulus.

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Question 4 (continued)

Source 2

Now watch the video ‘Waste not, want not: a home-grown plan to turn plastic and tyres into fuel’ about a scientific investigation.

https://www.youtube.com/watch?v=Psg9jz7LVNA

Reproduced with the permission of Professor Sankar Bhattacharya

(a) Compare the information in the two sources and discuss the possible influence of current economic issues and the political climate on this type of scientific research.

(b) Propose a relevant question for future research in this area and a methodology that could be used to address the problem of conflicting results.

End of Question 4

8

5

Questions in this part may have a range of values. In this example the maximum item value is 8.

In this question, students are required to watch a video.

https://www.youtube.com/watch?v=Psg9jz7LVNA

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Section II

Part B – 15 marksAttempt Question 5

Your answers will be assessed on how well you:● demonstrate knowledge and understanding relevant to the question ● communicate ideas and information using appropriate scientific language● present a logical and coherent response


Penicillin was discovered in London in September of 1928. Doctor Alexander Fleming was a bacteriologist who worked at St Mary’s Hospital, London. It is reported that after he returned from a summer vacation in Scotland he found a messy lab bench and a good deal more.

Upon examining some colonies of Staphylococcus aureus, Fleming noted that a mould called Penicillium notatum had contaminated his Petri dishes. After carefully placing the dishes under his microscope, he was amazed to find that the mould prevented the normal growth of the staphylococci.

It took Fleming a few more weeks to grow enough of the mould so that he was able to confirm his findings. His conclusions turned out to be phenomenal: there was some factor in the Penicillium mould that not only inhibited the growth of the bacteria but, more important, might be harnessed to combat infectious diseases.

Reproduced with the permission of Dr Howard Markel https://www.pbs.org/newshour/health/the-real-story-behind-the-worlds-first-antibiotic

To what extent do discoveries in science occur as a result of planned experiments? In your answer include reference to the stimulus provided and your Scientific Research Project.

This question requires students to refer to their Scientific Research Project.

Questions may require students to integrate the information in the stimulus with their experiences of their own project. Responses should demonstrate understanding from the student project as well as interpretation of the stimulus.

This extended-response question will have an expected length of approximately 600 words.

This is an example of an extended-response question. This question has a rubric that shapes the marking guidelines for this question.

©2018NSWEducationStandardsAuthority

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NSW Education Standards Authority

HSC Science Extension Sample Questions Marking Guidelines

Section I

Question 1 Criteria Marks

• Clearly justifies valid conclusions • Demonstrates comprehensive understanding of the mean, standard

deviation and t-test analysis • Clearly relates the mean, standard deviation and t-test analysis to the

conclusion

6

• Justifies conclusions • Demonstrates a sound understanding of the mean, standard deviation

and t-test analysis • Links the mean, standard deviation and t-test analysis to the conclusion

4–5

• Demonstrates some understanding of the mean and/or standard deviation and/or t-test analysis 2–3

• Provides some relevant information 1

Sample answer: The scientists set up a null hypothesis that there is no difference between the means of the two treatments. The alternative hypothesis is that there is a difference between the two means. They carried out a 2-tailed t-test which showed that the t Statistic is larger than the t Critical. The p value is 4.00 × 10–27 which is much smaller than the p value of 0.001 the scientists had decided on at the start of the experiment. Since p < 0.001, the scientists can reject the null hypothesis and accept the alternative hypothesis. They can say that there is a statistically significant difference between the means of the two treatments, and that the strength of concrete in Treatment 2 is greater than that of Treatment 1. However, the t-test on its own cannot be used to determine whether the treatments are fit for the intended purpose. The required minimum strength for the intended purpose is 22 MPa. From the data we can see that Treatment 1 would not meet the requirement, as the mean of 21.93 MPa is less than the required 22 MPa. For Treatment 2, the mean value is 23.40 MPa, which is above the

NESA 2019 HSC Science Extension Marking Guidelines

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minimum strength. However, if the standard deviation is large than it could be possible that some concrete produced with Treatment 2 would not meet the minimum strength. Most of the concrete produced with Treatment 2 needs to be above 22 MPa. Almost all the data in a normal distribution is within 3 standard deviations from the mean.

23.40 – (3 × 0.28) = 22.56 Since 22.56 MPa is still well above the minimum strength of 22 MPa, the scientists can be confident that Treatment 2 satisfies the minimum strength requirements. In summary, the scientists checked that they could use the t-test with their data and then carried out the test. Their analysis showed that there is a statistically significant difference between the means, with Treatment 2 having the higher mean. The mean for Treatment 1 is below the required minimum strength so it is not fit for the intended purpose. The mean for Treatment 2 is higher than 22 MPa and the scientists established that almost all concrete treated with Treatment 2 would have a strength higher than 22 MPa. The scientists can recommend the use of Treatment 2 for strengthening the concrete for the intended purpose.

In Question 1, students are expected to demonstrate an understanding of several related aspects of the information in the t-test analysis. Students need to understand how to interpret the statistics in relation to the scenario presented.


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Question 2 Criteria Marks

• Provides a plan which outlines the instruments, variables and sample data collection suitable for testing both research questions

• Demonstrates an understanding of the data required to test the research questions

• Outlines the different types of analysis possible for each of the two research questions

6

• Provides a plan which lists instruments and variables • Demonstrates an understanding of some data required • Outlines analysis suitable for one or both research questions

4–5

• Provides a plan with general information about some instruments or variables

• Makes some reference to data 2–3


Answers could include: For the research plan, the researcher needs to identify variables, instruments and the sample; then they need to collect data, analyse and interpret. For question i), the two variables are: • The seal is submerged under water (YES) or the seal is above water (NO). • The heart rate of the seal. Instruments

• The researcher could use instruments that sense if there is water surrounding the instrument or not. If the instrument is attached to the seal, when the seal is submerged, the instrument is submerged.

• The instruments to measure their heart rate would be attached to the seals. Sample

Using several seals would allow the researcher to check the consistency of the data across gender, age and size of the seals. Conducting research, collecting data

The researcher will need to complete an ethics procedure. The researcher would need to plan where they will find the seals and who will help them. The researcher will need to place the instruments on the seals in a safe manner, avoid irritating the seal and securely fasten the instruments. With modern technology, the data will be collected continuously so they need to check that the signal can be received. Analysis and interpretation

The data will need to be extracted and explored. If the data satisfies the assumptions then a t-test could be carried out. The t-test would test if the mean heart rate is different when the seals are submerged compared to when the seals are not submerged. The researcher could check if other variables, like gender, age and size have an effect. For question ii), the two variables are: • The time the seal is submerged under water or the seal is above water.


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• The heart rate of the seal. For question ii), the instruments, sample and data collection will be the same as for question i) except that the instrument that collects heart rate and determines when the seal is under water will also need to record total time the seal spends under water. Analysis and interpretation

The correlation between dive time and heart rate would be investigated.


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Section II Part A

Question 3 (a) Criteria Marks

• Justifies a range of ethical protocols relevant to the scientific study 5 • Justifies some ethical protocols relevant to the scientific study 3–4 • Provides an ethical consideration in the scientific study 2 • Provides some relevant information 1

Answers could include: The researchers would need to submit an application to the relevant Human Ethics Committee to get the ethical framework approved before the study is undertaken. Modern ethical frameworks require researchers in a study like this to inform patients about the methods to be used, how the data is to be analysed, stored and reported, and any benefits and risks they might experience associated with the research. The researchers must obtain informed consent and ensure confidentiality and anonymity. Patients are highly unlikely to be in a state to comprehend the study and provide informed consent. Researchers should follow up with patients after they have recovered and confirm that they are willing to be included in the study. If the patient wants their data to be removed from the study, the researcher is ethically bound to comply with this request. Justification for the ethical protocols may include: • To reduce any adverse risks to patients • To ensure patient privacy, complying with legal privacy requirements • To ensure that the independence and freedom of the patient is not compromised • To ensure an accountable and transparent process for conducting research.


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Question 3 (b) Criteria Marks

• States a research question which can be answered using the stimulus • Justifies an appropriate conclusion

4

• States a relevant research question and a conclusion 2–3 • Provides some relevant information 1

Sample answer: The research question for this study can be ‘Is inhaling isopropanol more effective than Zofran in reducing the severity of nausea in emergency room patients?’ The results show that the greatest apparent reduction in severity occurred when isopropanol was administered with a placebo. The average severity of nausea dropped by approximately 30 on the severity scale. This reduction was greater than when the isopropanol was administered with Zofran, and much greater than when Zofran was administered without isopropanol. The conclusion is: The trend in the data shows that inhaling isopropanol has an effect on the reduction of nausea severity in emergency room patients. However, this is a trend only. We cannot be more firm as no statistical testing has been carried out. Question 3 (c)

Criteria Marks • Makes a judgement on the validity of this study, with specific reference to

key aspects of the research plan • Supports suggested improvements

6

• Describes aspects of the research plan that refer to its validity • Suggests ways to improve the study

4–5

• Provides an outline of aspect(s) of the study that refer to its validity • Suggests a valid way in which the study could be improved OR • Shows some understanding of validity and how to improve the study

2–3


Answers could include: To assess the validity we have to ask: Does the information provided address the research question? Is the research plan good enough to address the research question? This means we need to look at the variables, including controls, instruments, sample, data, analysis and interpretation. Variables and controls: The investigation includes appropriate variables as it tests isopropanol alone, Zofran alone and a combination of isopropanol and Zofran. The placebo performs the role of a control – allowing the researchers to directly compare the effect of isopropanol with and without Zofran. In a way, the saline also acts as a placebo allowing Zofran to be combined with a placebo inhale treatment. Instrument: We are told that the researchers used established protocols for measuring nausea severity.


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Sample: The researchers have selected a large enough group of participants, and selected them randomly from a convenience sample. The report also refers to ‘emergency rooms’ which means from more than one hospital. So it looks like the sample is reasonable. Data: The researchers have provided the average severity of nausea before and after each treatment in the form of a bar graph. The averages do not go beyond 50, so that is a worry. But we have no idea of the spread or standard deviation so maybe there were patients who were more than 50 on the scale. Also, it is likely that patients recording higher values would be taken to intensive and therefore could not be in the study. Analysis and interpretation: The report has not provided a specific research question. The information and analysis provided does not allow us to answer a specific research question. The report has not provided the spread or standard deviation of the data, so we cannot say whether there is any ‘overlap’. Additionally, it has not identified any statistical test that could be carried out with the data or presented a detailed analysis. Improvements: • Larger sample size • Demographic data • Across different sites, number of sites is presented • Reporting of statistical analysis, standard deviations and appropriate statistical tests.


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Question 4 (a) Criteria Marks

• Compares the information in the two sources • Shows a comprehensive understanding of how scientific research is

influenced by economic and political issues • Communicates ideas and information using appropriate scientific

language

7–8

• Some comparison of the sources evident • Shows a high-level understanding of how scientific research is influenced

by economic and political issues • Communicates ideas and information using mostly appropriate scientific

language

5–6

• Shows a limited understanding of how scientific research is influenced by other factors

• Communicates information using basic scientific terms 3–4

• Provides some relevant information • Communicates in general rather than scientific terms

1–2

Sample answer: The results from the first investigation suggest that the fuel produced from waste plastic pyrolysis is not as efficient as diesel, although the authors point out that these findings differ from those reported in the literature. In the second investigation, the waste plastic pyrolysis fuel was found to enhance the efficiency and the burn time of the diesel fuel and reduce the polluting effect of the car emissions. It is difficult to compare the results of these two investigations directly as the waste plastic pyrolysis fuel was mixed with the diesel fuel in the second investigation as opposed to being used on its own in the first investigation. In order to draw a valid scientific conclusion we need more information than is provided in these two sources. The investigations described in the two sources have a similar scientific question driving their methodologies: they are investigating the use of waste plastic pyrolysis fuel as an alternative to diesel fuel. They are both using similar waste plastic pyrolysis fuel, however, in the first investigation they use the waste plastic pyrolysis fuel on its own and compare it to diesel whereas in the second investigation the waste plastic pyrolysis fuel is added to diesel. The reliability and validity of the data from these two sources should also be questioned. One is a student report, with the authors admitting that their study was hindered by having limited access to materials and advanced technologies to test their question. The second source of information is an industrial firm that is already producing fuel from waste plastic pyrolysis and is therefore invested in showing that the waste plastic pyrolysis fuel is a viable alternative to diesel fuel. Their results for plastic waste pyrolysis fuel appear promising, both from a fuel efficiency and reduced emissions perspective, but we need more information in order to compare these results with those reported in other studies. In addition, we need to take other questions into account. First, we need to consider the question raised by the students doing the first investigation, that is, ‘whether waste plastic pyrolysis fuels result in a net gain of energy’. Second, the cost of removing plastics from the environment must also be taken into account when considering the reuse of waste plastics. The fact that the manufacturer is planning to increase the production of fuel from waste plastic pyrolysis would suggest that the technology is proven and economically viable.


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It is certainly possible that large companies that have invested large sums of money into the fossil fuel industry would not wish an alternative fuel to be readily available. Similarly, much political power might rest on the support of powerful industrialists but some political power may rest on the support of conservationists concerned with the devastating effect plastics have on sea life and the food chain. Scientists have raised the alarm and popular media outlets are increasingly publishing stories about the effects of plastics on the environment. Concern has reached such a level that governments around the world are introducing legislation to ban the sale of single use plastics. Economic and political considerations exert a significant influence on the funding of scientific research. Scientific research has for a very long time been dependent on financial support from government and wealthy private benefactors. This means that it may not be possible to conduct certain research if the funds needed to pay the scientists and build the machines, instruments and devices are not available. This means that in some instances in some countries the government may not have sufficient funds to fund even the most urgent research. Question 4 (b)

Criteria Marks • Proposes a relevant question for future research in this area • Describes an appropriate methodological approach that could be used

which addresses the problem of conflicting results 5

• Proposes a question for future research in this area • Describes a methodological approach that could be used which may

address the problem of conflicting results 4

• Proposes a question for future research in this area OR • Describes a methodological approach that could be used which may

address the problem of conflicting results

3

• Outlines either an area for future research or some method that could be used 2


Answers could include: A relevant question for future research: Is the waste plastic pyrolysis fuel, used alone, as efficient as diesel fuel? In order to answer this question and avoid conflicting results the researchers will need to define: • Variables, controls, instruments, sample, data:

– use high-quality materials and the best available technologies for testing and measuring

– test the waste plastic pyrolysis fuels and the diesel fuel on the same vehicle or engine type in similar conditions or over a range of defined conditions for each experiment

– measure the same factors for each of the fuels being tested, eg fuel efficiency, emissions, and thermal energy produced.


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• Analysis and interpretation: – they would need to carry out sophisticated testing, not just of the outcomes but multiple

outputs – since this is a sociopolitical issue, environmental, cost, manufacturing, industrial details

would need to be factored in – there are ethical issues and biases to be considered in the interpretation, such as who

should fund the research; pressures on the independence of the researcher to present results which could be counter to the funding body’s interests.


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Question 5

Criteria Marks • Shows a comprehensive understanding of scientific investigations and

plans • Communicates ideas and information using appropriate scientific

language • Presents a logical and coherent argument integrating understanding from

the stimulus and their scientific research project

13–15

• Shows a high-level understanding of scientific investigations • Communicates ideas and information using mostly appropriate scientific

language • Presents an argument which includes reference to the stimulus and their

scientific research project

10–12

• Shows a sound understanding of scientific investigations • Communicates ideas and information using some scientific language • Presents some logic and structure in their argument

7–9

• Shows a limited understanding of scientific investigations • Communicates information using basic scientific terms • Presents some structure in their argument

4–6

• Provides some relevant information • Communicates in general non-scientific language

1–3

Sample answer: While stories of happy accident or coincidence in science are often the most memorable, even accidental discoveries have to be validated by applying the rigour of the scientific method. Fleming may have been remembered for this ‘happy accident’ but it was consolidated in the same way I approached my own scientific research project, with careful planning and a systematic approach. Fleming’s discovery was in the first instance due to chance. On returning from holiday, he found his lab bench in a mess and the staphylococci bacteria present on some Petri dishes but not on others. Those Petri dishes with fewer bacteria also happened to contain a mould known as Penicillium notatum. Fleming did not know how the mould contaminated the Petri dishes but was curious about the link between the mould and the bacteria. He then initiated a series of experiments that confirmed the chance discovery that the mould somehow prevented the bacteria growth. Had this accident not occurred, this discovery may not have happened in the way it did. However, he did not rely on the accident but also conducted a series of planned experiments to confirm his suspicions and explore the strange occurrence further. It would have been in this period of planned experimentation that alternatives were ruled out and Fleming ensured that the experiments were valid to be certain of his conclusion that the mould can be used to combat disease. In this way, the ‘accident’ played a part in scientific progress, but it went hand-in-hand with planned experimentation. In my investigation involving rolling cylinders with rubber bands and masses hanging in them, I followed a very meticulous plan which I adhered to with little adaptation. It ultimately produced results that contributed to what we know about the topic. My project involved

The marking guidelines incorporate the specific requirements of the question and the general requirements contained in the rubric.


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analysing the motion of a rolling cylinder that had a mass attached internally using a rubber band. After careful review of the literature, including making notes and summarising, I understood that little was known about this phenomenon due to the complex way in which various factors interacted with each other (the tension in the bands, the location of the masses and the fact that the cylinders could roll or slip). I generated my final research question, focusing on the way the masses were hung in the cylinder. I developed a plan with milestones and this helped guide me through the experimental portion of my project. In particular, I scheduled all the data collection for the one day. This ensured I was able to use the same equipment in approximately the same (weather) conditions. Since the experiment involved rolling cylinders down a ramp with different masses, this was achievable. The data analysis was scheduled for the following days and weeks. I scheduled in another day in case any part of the experiment needed to be repeated, however, this was not necessary in this case. I made sure to carefully note the process in my portfolio and I communicated my results in a Scientific Research Report. My results help to provide clarity around the role of mass distribution in cylinder rolling; contributing a small part of the puzzle related to this kind of motion. Overall, this approach very much supports the view that scientific discoveries occur due to planned experiments. While science is often popularised by referring to factors such as chance, it is planned and systematic experimentation that leads to scientific progress. Fleming’s discovery was due to chance but his final results involved planned experimentation, just as the results from my own project relied on planned experiments. Happy accidents do occur, but planned experiments are at the heart of scientific progress.

This answer is approximately 600 words.


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HSC Science Extension Sample Questions Mapping Grid

Section I

Question Marks Content Syllabus outcomes Targeted performance

bands

1 6 Module 3: The Data, Evidence and Decisions SE-4 E2–E4

2 6 Module 2: The Scientific Research Proposal SE-3, SE-6, SE-7 E2–E4

Section II Part A


bands

3 (a) 5 Module 2: The Scientific Research Proposal SE-3 E2–E4

3 (b) 4 Module 3: The Data, Evidence and Decisions SE-7 E2–E3

3 (c) 6 Module 3: The Data, Evidence and Decisions SE-5, SE-7 E2–E4

4 (a) 8 Module 1: The Foundations of Scientific

Thinking Module 4: The Research Report

SE-2, SE-5, SE-7 E2–E4

4 (b) 5 Module 1: The Foundations of Scientific


SE-2, SE-5, SE-7 E2–E4

Section II Part B


bands

5 15 Module 1: The Foundations of Scientific


SE-2, SE-7 E2–E4

Documents

2019 Science Extension Sample Paper