Investigating Science 2020 HSC exam pack

Students should:

• read the question carefully to ensure that they do not miss important components of the question
• have a clear understanding of key words in the question and recognise the intent of the question and its requirements
• plan the response to assist in the logical sequencing of information
• integrate relevant scientific terms into their responses
• engage with any stimulus material provided and refer to it in their response(s)
• show all working in calculations and include correct units
• present a logical and succinct response that addresses the question
• review their response(s) to ensure that it addresses the question requirements.

Question 21

In better responses, students were able to:

• outline TWO experiments and provide correct qualitative data for both
• use the term “dephlogisticated air” in the correct context
• provide TWO different experiments conducted by Priestly, for example, a closed container with Mercury Oxide as well as his works with rats, candle and jar
• give a correct outline of Priestley's experiments with examples of quantitative data collected
• explicitly identify data and compare them.

Areas for students to improve include:

• referring to data
• providing a succinct answer
• demonstrating a clear understanding of Priestley’s work.

Question 22

In better responses, students were able to:

• successfully plot the points given accurately and draw an acceptable line of best fit
• show awareness of the outlier (last data point) into their line of best fit trajectory
• use an extrapolation technique to correctly give an accurate estimate
• identify the potential for a non-linear trend based on the apparent outlier
• show an understanding of the validity of extrapolating a graph over large intervals to prove that 300kPa was an accurate prediction
• show an understanding of validity by describing controlled variables in the experiment
• make a judgement about the validity of the technique
• either acknowledge and/or ignore the outlier
• use the inverse relationship shown on the x-axis to correctly perform the required calculation to enable the value to be interpolated.

Areas for students to improve include:

• drawing a correctly determined line of best fit using a ruler
• selecting an appropriate graph to plot
• differentiating between validity and reliability
• recognising the inverse scale of the axis
• processing and analysing data from a graph
• expressing units in calculated data
• performing calculations by applying correct formulae.

Question 23

In better responses, students were able to:

• identify peer-review as the required response and explain with a specific example how fraud was uncovered
• make correct reference to scientists' names
• relate the cause and consequence.

Areas for students to improve include:

• providing specific examples
• explaining how peer-review can identify scientific flaws in research
• giving a clear description of the process
• providing the context of ‘publish or perish’ in the question.

Question 24

In better responses, students were able to:

• identify that the two axes had different scales
• explicitly link the presentation of data to misrepresentation of information
• engage with the graph to explain the data
• demonstrate their understanding of statistics and data representation and how it influences individuals and the wider population.

Areas for students to improve include:

• using all information presented in graphical form to read data correctly from a graph.

Question 25

In better responses, students were able to:

• identify that the original sample size only contained one test subject and that further repetitions are needed to increase reliability through the consistency of results
• clearly identify that consent should be granted in order to meet ethics guidelines for patient safety OR privacy protection
• identify an unethical practice
• identify that testing in an agar plate is the preferable first step to ensure efficacy of antibiotics in order to reduce risk of harm to humans and animals
• suggest animal testing following ethical guidelines to identify any potential risks.

Areas for students to improve include:

• addressing the initial sample size
• identifying why repetitions are needed to improve reliability
• explaining the role of the ethics committee.

Question 26

In better responses, students were able to:

• show knowledge related to atomic theory and link this to a technological development
• use relevant examples such as, linking the Large Hadron Collider to the discovery of the Higgs Boson or linking Rutherfords’ gold foil experiment to the discovery of the nucleus
• identify relevant technology
• describe features of radioactivity, for example, gamma radiation and link more than one feature of radioactivity to radiotherapy
• outline that radiation can kill cells and link this to cancer treatment
• outline how radiotherapy has improved, for example, by becoming more accurate in targeting tumours to avoid healthy tissue
• provide examples of isotopes, for example, iodine, cobalt-60 and technicium that are used to treat cancer
• outline historical examples such as, Marie Curie or Chernobyl to show how the dangers of radioactivity have been discovered.

Areas for students to improve include:

• linking specific technology to developments in atomic theory
• outlining the relevance of certain technologies which are not clearly linked to the development of atomic theory, for example, identifying microscopes
• providing scientific detail about radioactivity.

Question 27

In better responses, students were able to:

• outline how pseudo-sciences use scientific language
• apply experimental design principles from Modules 5 and 7
• outline how to change the independent variable, measure the dependent variable and compare data to test correlation claim
• design valid experiments to produce accurate and reliable data.

Areas for students to improve include:

• using relevant terms rather than providing generalised information
• designing a valid experiment to test an observation.

Question 28

In better responses, students were able to:

• identify the double helix structure and link it to the method that the shape was determined by x-ray
• identify components of the structure of DNA using clear understanding of bases and nucleotides
• name TWO DNA technologies and link knowledge of the structure to technology
• provide an in-depth knowledge of the processes.

Areas for students to improve include:

• describing new information, for example, about the structure, that was gained about DNA
• linking X-ray imaging to the understanding of DNA structure
• providing a clear description of how the technology chosen works.

Question 29

In better responses, students were able to:

• provide a relevant, testable statement
• provide correct labels and units on the correct axes
• draw a graph with the correct shape to represent the Doppler Effect
• relate the experimental results to the relevant scientific phenomenon
• accurately explain changes in wave frequency or pitch of the sound
• explain the link between the change in wave frequency according to Doppler shift.

Areas for students to improve include:

• applying the key provided correctly for each of the trumpeters
• sketching a line to show a change in pitch
• referring to relevant scientific phenomena such as, the Doppler effect in their answer
• referring to the experiment data when explaining results.

Question 30

In better responses, students were able to:

• demonstrate a detailed knowledge of TWO different water treatment methods
• provide a detailed explanation of the common water treatment methods including filtration and disinfection to remove sediment and microbes
• link their judgement to relevant scientific research, including examples such as, the development of safe drinking straws, desalination and reverse osmosis.

Areas for students to improve include:

• communicating using relevant terminology rather than providing generalised information about water treatment methods and scientific research
• demonstrating a clear understanding and judgement of developments gained through scientific research that have improved the health and wellbeing of people around the world such as, the use of purification tablets.

Question 31

In better responses, students were able to:

• identify conflict of interest, bias and/or evidence-based science as reasons for different statements
• identify the scientific and societal pressures
• integrate information in the stimulus with content studied in the course.

Areas for students to improve include:

• discussing issues supported by points for and against
• using specific scientific terms and definitions
• demonstrating a clear understanding of science and society.

Question 32

In better responses, students were able to:

• make a clear judgement
• correctly identify that the summary was unreliable
• demonstrate a thorough understanding of reliability relating to secondary sources
• demonstrate a sound understanding of reliability of primary data/first-hand investigations, for example, requiring repetition and/or peer review.

Areas for students to improve include:

• assessing the reliability of the presented data with supported reasons
• distinguishing between reliability of primary and secondary sources.