Investigating Science 2021 HSC exam pack

Students should:

• read the question carefully to ensure that they understand its intent and 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.

Question 21

In better responses, students were able to:

• outline why scientific regulation in science is needed and give a relevant example
• identify ethics, validity or safety as a need for regulation and link to a relevant example
• use famous historical experiments or events as their example and link to regulation, for example the Warren and Marshall experiment or the Tuskegee Study.

Question 22

In better responses, students were able to:

• explicitly compare the two different types of mice and diets and provide the purpose for the comparisons
• correctly identify a structural feature of DNA and explain how the mentioned structure allows the organism to be modified genetically
• identify that there were two independent variables.

Areas for students to improve include:

• being explicit about the groups being compared and explaining the reason for the comparison
• use scientific terms that does not repeat the wording in the original question.

Question 23

In better responses, students were able to:

• clearly differentiate between validity and reliability
• outline a method that could be used to check the validity and reliability of secondary sources.

Areas for students to improve include:

• understanding the difference between primary investigations and secondary sources.

Question 24

In better responses, students were able to:

• demonstrate an understanding of Spencer’s work
• discuss how Spencer followed a linear model and how he deviated.

Areas for students to improve include:

• demonstrate a clear understanding of the linear model.

Question 25

In better responses, students were able to:

• extrapolate information from the graph and refer to it in their response
• recognise the appropriate trend.

Areas for students to improve include:

• referring to each incident in any given stimulus
• using scientific terms, for example, using the term ‘plateaued’ or ‘remained unchanged’.

Question 26

In better responses, students were able to:

• identify the units for both distance and speed
• demonstrate consistency with units, for example, distance (m) and speed (m/s)
• construct a table with appropriate headings including time-period, distance and speed
• accurately transfer the data from the graph to the table
• make clear connections with speed, distance and time
• provide a statement that recognised that an increase in time results in an increase in distance when speed is constant
• rearrange the speed formula (speed = distance/time) to make time the subject
• use data obtained from calculations to support the connection between time and distance when speed is constant.

Areas for students to improve include:

• understanding that the question requires a table, not a graph
• understanding that the question is not about experimental design but the relationship between time and distance
• identifying that speed is constant
• identifying that time is the variable that is required for calculation, not speed.

Question 27

In better responses, students were able to:

• demonstrate an understanding of Jenner’s experiment
• provide direct and detailed comparison between Jenner’s experiment and a vaccination program
• understand information that would keep the trial ethical.

Areas for students to improve include:

• using comparative terms, rather than listing/individualising the factors.

Question 28

In better responses, students were able to:

• provide clear outlines of theory and law when used scientifically (a)
• identify evidence as a key component of scientific theories in (a)
• identify quantitative data or the ability to be empirically tested as a key component of scientific laws in (a)
• provide relevant examples that were scientifically valid in (a) such as the Big Bang theory, evolution and Newton’s Laws of Motion
• reference the stimulus material in (b) rather than just give generalised information on a theory and hypothesis
• evaluate by providing more than one argument in (b)
• demonstrate the difference between a hypothesis and theory, as the quote in (b) suggests that they are the same
• clearly state that the terms were appropriate or not as part of their evaluation for (b)
• identify that the quote was deceptive, leading the reader to feel that climate change was only a hypothesis
• identify than gravity can be considered as a law rather than a theory in (b) (although both terms could be considered accurate depending on the aspect of gravity being considered; Newtonian or Einstein’s theories of relativity).

Areas for students to improve include:

• providing more detail than an overview of theory and law in (a). For example, giving evidence and the types of concepts involved
• distinguishing between scientific and non-scientific theories in (a); and providing relevant examples that are scientifically appropriate, for instance, Flat Earth theory was not relevant
• clearly differentiating between a law and a theory in (a), usually by relating them to the concepts they describe or explain
• using scientific language to describe hypotheses, theories and laws, avoiding colloquialisms, for example, ‘set in stone’ or ‘educated guess’
• understanding of the definition of a hypothesis in (b) and describing a ‘testable statement’ rather than an ‘educated guess’
• comprehending the stimulus material before answering the question
• providing more than only a definition of the terms and applying their understanding to the quote itself in (b).

Question 29

In better responses, students were able to:

• outline how a placebo and double-blind trial could be carried out
• identify how sample size and/or sample selection is important in a double-blind, placebo trial
• identify that weight difference (before and after trial) is required as the dependent variable.

Areas for students to improve include:

• understanding variables including the independent (placebo trial), the dependent (weight), and controlled variables (double-blind)
• making explicit reference to stimulus in design of trial.

Question 30

In better responses, students were able to:

• clearly define the halo effect as part of their discussion
• use scientific terms such as ‘cognitive bias’ or ‘psychological effect’
• use an example to support their definition, for example, celebrities paid to be in advertisements
• make a connection between the halo effect and Einstein’s celebrity status or fame, rather than refer to the halo effect as being due to his scientific knowledge
• explain that it is possible that the halo effect, combined with scientific expertise, could produce a stronger halo effect
• explain the role of the halo effect in influencing the president
• show critical thinking by explaining that the president may have started the research anyway, due to the war
• provide more than one reason for Einstein being either an example of the halo effect or not.

Areas for students to improve include:

• providing a critical argument rather than just outlining that Einstein was a celebrity, trustworthy or a genius
• avoiding irrelevant background information, for example, many students wrote on the ethics or negatives of nuclear warfare or the history of Einstein’s career rather than the halo effect
• describing the halo effect rather than the Hawthorne effect.

Question 31

In better responses, students were able to:

• use all the data in the table to assess the claim
• use the data to calculate percentages, showing working (data processing)
• provide evidence for the multiple views of residents from the data.

Areas for students to improve include:

• selecting examples that are not controversial or specific to one dam
• understanding that surveys do not include every individual opinion
• using all the data that is given.

Question 32

In better responses, students were able to:

• understand the difference between reliability, validity, and accuracy
• provide an analysis of the results of both groups
• analyse specific error that could occur (systematic) using the gathered data
• appropriately use the stimulus
• correctly interpret graphs
• link stimulus to accuracy correctly and use the stimulus in their response.

Question 33

In better responses, students were able to:

• write a hypothesis and conclusion that relates the independent and dependent variables
• incorporate the information in the stimulus (jar, mouse, plant)
• link the need for controlled variables to accuracy and validity
• use the terms accuracy, validity and reliability consistently and appropriately
• use the appropriate nomenclature
• identify qualitative and quantitative data.

Areas for students to improve include:

• referring to the stimulus and not confusing Priestley’s experiments with Von Helmont or confusing the original experiment with the improved experiment
• identifying the variables kept constant rather than listing independent and dependent variables
• suggesting a change to the independent variable, which changes the experiment rather than suggesting ways to improve the experiment.

Question 34

In better responses, students were able to:

• identify economic and/or social and/or political factors (with examples)
• outline the effect these factors had on the choice of scientific research
• provide a judgement regarding the effect
• use at least two different examples as evidence in their evaluation.

Areas for students to improve include:

• understanding what economic, political, and social factors are
• outlining a correct link between factor and influence
• separating factors and responding to each
• understanding that the key word ‘evaluate’ requires a judgement to be made.