What Is a Depth Study in HSC Science?

A student spends three lessons measuring how a trolley moves down a ramp, records their results, and draws a graph. Another student spends three lessons investigating how battery chemistry affects energy storage by analysing published scientific data.

Could either activity be an HSC Science depth study?

Yes. And neither needs to look like a traditional school science experiment.

A depth study is an opportunity to investigate a scientific question in greater detail, using the knowledge and scientific skills developed throughout your course. It might involve designing an experiment, analysing existing research, using a computer simulation, or conducting fieldwork.

The important distinction is that a depth study is about developing your understanding through scientific investigation. It isn’t simply a longer practical report or a research assignment with a scientific topic.

There are also specific NESA requirements, and they depend on which syllabus your cohort is studying. This is particularly important during the transition to the new 2025 Science syllabuses.

01What is a depth study in HSC Science?

A depth study is a targeted scientific investigation that allows you to explore a concept from your course in greater detail.

Rather than simply learning an established scientific principle, you use that knowledge to investigate a question, make predictions, collect or analyse evidence, and communicate what you discover.

Think about the difference between following a recipe and experimenting with it.

In a normal practical, your teacher might give you a procedure and ask you to follow it to demonstrate a particular scientific principle.

In a depth study, you have more responsibility for the investigation. You might choose a question, decide how to investigate it, determine what evidence you need, and evaluate whether your results support your prediction.

The analogy isn’t perfect. You aren’t free to investigate absolutely anything. Your depth study must connect to the relevant syllabus, address its requirements, and fit within your school’s teaching program.

What skills does a depth study develop?

Depth studies are closely connected to a set of skills called Working scientifically.

These skills involve:

• Questioning and predicting: Identifying a scientific question and making a prediction based on existing knowledge.
• Planning investigations: Deciding how to investigate the question and what variables or evidence need to be considered.
• Conducting investigations: Carrying out practical investigations, fieldwork, simulations, or other appropriate research activities.
• Processing data and information: Organising measurements and information into useful forms, such as tables and graphs.
• Analysing data and information: Identifying patterns, interpreting results, and evaluating evidence.
• Problem-solving: Applying scientific knowledge to investigate problems and develop explanations.
• Communicating: Presenting scientific findings clearly and accurately.

You won’t necessarily demonstrate every skill in every individual depth study. The exact requirements depend on your syllabus version.

02What can a depth study involve?

One of the biggest misconceptions is that every depth study must involve a laboratory experiment followed by a formal written report.

That’s not the case.

NESA allows different approaches to scientific investigation. The appropriate format depends on the course requirements, the scientific question, and the way your teacher structures the activity.

Some possibilities include:

A depth study can also involve a combination of these approaches.

For example, you might conduct an experiment, compare your results with published scientific data, and present an explanation of any differences.

The key is that the activity must be a genuine scientific investigation that meets the requirements of your course.

03What are the current NESA requirements?

This is where you need to be careful.

NSW is transitioning to new Stage 6 Science syllabuses released in 2025. However, the new syllabuses are not all being implemented in the same year.

As at 8 November 2026, students need to distinguish between the existing 2017 syllabuses and the replacement 2025 syllabuses.

The existing 2017 Science syllabuses

If you’re studying Biology, Chemistry, Physics, or Earth and Environmental Science under the 2017 syllabus, the depth study requirements include:

• A minimum of 15 hours of in-class time allocated to depth studies in Year 11.
• A minimum of 15 hours of in-class time allocated to depth studies in Year 12.
• At least one depth study in each year.
• The Working Scientifically outcomes of Questioning and Predicting and Communicating must be addressed in both years.
• Each depth study must address at least two additional Working Scientifically skills outcomes and further develop at least one Knowledge and Understanding outcome.

These hours are included within the 120 indicative hours allocated to each course year.

Investigating Science is an exception. Under its existing 2017 syllabus, 30 hours of course time are allocated to depth studies in each of Year 11 and Year 12.

A depth study can be one investigation or activity, or a series of investigations and activities. It can also extend concepts across different modules.

For students following the 2017 courses, the familiar Module 1-8 structure remains relevant.

You can check the existing requirements through the official NESA course pages:

• Biology Stage 6 Syllabus (2017)
• Chemistry Stage 6 Syllabus (2017)
• Physics Stage 6 Syllabus (2017)
• Earth and Environmental Science Stage 6 Syllabus (2017)
• Investigating Science Stage 6 Syllabus (2017)

The new 2025 Science syllabuses

The replacement syllabuses introduce a different depth study allocation.

For the new Biology, Chemistry, Physics, and Earth and Environmental Science courses:

• 10 hours of depth studies are included in the Year 11 course.
• 10 hours of depth studies are included in the Year 12 course.
• At least one depth study must be completed in each year.
• Each depth study must include Working scientifically content from Questioning and Predicting, as well as content from at least one other focus area.
• Depth studies may be completed individually or collaboratively.

The new requirements are therefore not identical to those in the 2017 courses.

The implementation dates are also important.

This means a student beginning Year 11 Physics in 2027 follows the new syllabus, while a student beginning Year 12 Physics in the same year continues with the 2017 syllabus.

The same transition applies to Biology. Chemistry and Earth and Environmental Science move to the new syllabuses from 2028.

Investigating Science remains under its 2017 syllabus as at the date of this guide.

You can read the new requirements directly from NESA:

• Physics 11-12 Syllabus (2025)
• Chemistry 11-12 Syllabus (2025)
• Biology 11-12 Syllabus (2025)
• Earth and Environmental Science 11-12 Syllabus (2025)

The important thing is to check the syllabus that applies to your actual course, rather than relying on an older guide or assuming that everyone studying the same subject has identical requirements.

04What does a good depth study look like?

Knowing the requirements is one thing. Understanding what you might actually investigate is another.

Let’s consider two examples.

Example 1: A Physics depth study

Imagine you’re studying mechanics and become interested in how the height from which an object is released affects its final speed.

You could investigate:

How does the release height of a trolley affect its speed at the bottom of an inclined track?

This is a useful investigation because it connects directly to energy and motion.

You could approach the investigation as follows.

Step 1: Establish your prediction.

You predict that increasing the release height will increase the trolley’s speed at the bottom.

Why?

A trolley released from a greater height has more gravitational potential energy. As it moves down the ramp, some of this energy is converted into kinetic energy.

Step 2: Identify your variables.

• Independent variable: Release height.
• Dependent variable: Speed at the bottom of the ramp.
• Controlled variables: The trolley, track angle, track surface, and release method.

Step 3: Plan your measurements.

Release the trolley from several different heights and use a photogate to measure its speed at the bottom.

Repeat each measurement to improve reliability.

Step 4: Analyse your results.

Plot your measurements on a graph and look for a relationship between release height and final speed.

You should also consider whether friction, measurement uncertainty, and energy transferred into rotational motion affect your results.

Step 5: Evaluate your prediction.

Explain whether the results support your prediction.

If they don’t, investigate possible reasons. A result that differs from your prediction isn’t automatically a failed investigation.

The quality of the scientific reasoning matters more than whether you obtain the result you expected.

Example 2: A Chemistry depth study

Chemistry offers plenty of opportunities for investigating relationships between reaction conditions and chemical behaviour.

Consider this question:

How does the concentration of sodium hydrogencarbonate solution affect the initial rate of its reaction with excess ethanoic acid?

This investigation examines how concentration influences reaction rate.

You could develop the investigation in several stages.

Step 1: Make a prediction.

You predict that increasing the concentration of sodium hydrogencarbonate will increase the initial reaction rate.

The reasoning comes from collision theory. A higher concentration means more reactant particles in a given volume, increasing the frequency of collisions.

Step 2: Design a fair investigation.

Change the concentration of the sodium hydrogencarbonate solution while keeping the temperature, total solution volume, and acid conditions consistent.

The acid should remain in excess so that the comparison is meaningful.

Step 3: Collect data.

Use a gas syringe to measure the volume of carbon dioxide produced over time.

Repeat the experiment for each concentration.

Step 4: Process your results.

Plot gas volume against time.

The gradient of the initial section of the graph gives an indication of the initial reaction rate.

This is more informative than simply comparing the final gas volumes, because you’re investigating how quickly the reaction proceeds, not just how much gas is eventually produced.

Step 5: Evaluate your findings.

Consider whether the results support your prediction.

Discuss measurement uncertainty, consistency between trials, and whether your experimental conditions were properly controlled.

This is an example of how you can take a familiar Chemistry concept and investigate it through a focused scientific question.

Does a depth study have to involve an experiment?

No.

You could also investigate a scientific question using existing research and published datasets.

For example, a Chemistry student could investigate how different battery chemistries compare in energy density and cycle life.

Rather than constructing batteries, the student could:

• Identify two battery chemistries to compare.
• Develop a question and prediction based on their chemical properties.
• Locate published scientific data from reliable sources.
• Compare energy density and cycle-life measurements.
• Check whether the studies used comparable testing conditions.
• Explain the observed differences using chemical principles.
• Evaluate the limitations of the available evidence.

This is a secondary-source investigation.

Notice that the student is still asking a scientific question, making a prediction, analysing evidence, and applying course knowledge.

Simply collecting facts about batteries would not achieve the same purpose.

05How should you prepare for a depth study?

You don’t need to begin with an extremely complicated scientific question.

In fact, a narrow, well-designed investigation is usually much easier to manage than an ambitious topic that you cannot properly investigate within the allocated time.

Here are five useful steps.

1. Start with a specific question

Avoid questions that are too broad.

For example:

• Too broad: How does electricity work?
• More focused: How does the length of a copper wire affect its electrical resistance at constant temperature?

A useful research question should identify something you can investigate and connect to a concept in your syllabus.

2. Understand the scientific theory first

Before collecting data, make sure you understand the relevant scientific principles.

You should be able to explain why you expect a particular result.

This makes it much easier to develop a meaningful prediction and recognise when your results don’t match your expectations.

3. Plan how you will obtain evidence

Think about what information you need to answer your question.

If you’re conducting an experiment, identify:

• Your independent and dependent variables.
• The variables that need to remain controlled.
• The equipment and measurement techniques required.
• How many trials you will complete.
• Any safety or ethical considerations.

If you’re using secondary sources, consider the reliability of your sources, the methods used to obtain the original data, and whether different datasets can reasonably be compared.

4. Keep a record of your investigation

Don’t rely on remembering everything you did.

Keep track of:

• Your original research question and prediction.
• Your experimental procedure or research method.
• Raw measurements and observations.
• Graphs, calculations, and processed data.
• Sources of information.
• Changes you made to your method.
• Problems encountered and possible improvements.

This record is particularly useful when you need to explain how you reached your conclusions.

It also helps demonstrate your own contribution if you’re working collaboratively.

5. Understand exactly how your school will assess it

This is worth checking before you start.

NESA establishes the course requirements, but schools have discretion over their formal school-based assessment programs.

Your teacher should explain the task requirements, including the relevant outcomes, assessment criteria, and submission arrangements.

Find out:

• Whether you’re working individually or in a group.
• Whether you need a practical investigation or can use secondary sources.
• What format your final submission should take.
• How your work will be assessed.
• Whether you need to submit supporting research or experimental records.
• What assistance, including generative AI, is permitted.

A depth study doesn’t automatically mean you have to submit a 2,000-word scientific report.

Your teacher might ask for a written report, an oral presentation, a research assignment, or another suitable form of communication.

The format should match the investigation and the assessment requirements.

06Does a depth study count towards your HSC assessment?

It can, but there is an important distinction between completing a mandatory course requirement and completing a formal school-based assessment task.

NESA requires students to complete the depth study requirements specified in their course syllabus.

However, schools determine the number, type, and weighting of their formal in-school assessment tasks, subject to NESA’s course requirements.

This means there isn’t one universal depth-study assessment weighting that applies to every NSW school.

Your school might include a depth study as a formal assessment task, or use the work in another way within its teaching and assessment program.

There is also a relevant recent change to assessment rules.

From Term 4 2026, NESA’s ACE Rules limit schools to one take-home assessment task per Preliminary course and one per HSC course, each worth no more than 15% of the school-based assessment mark.

This limit applies to formal take-home assessment tasks. It does not mean that every depth study automatically carries a 15% weighting.

You can check the current rules through NESA’s formal assessment programs and tasks.

07Does a depth study affect your ATAR?

A depth study does not provide a separate ATAR bonus.

If your school includes it in a formal assessment task, your performance may contribute to your school-based assessment mark for that subject.

Your HSC course results then form part of the normal HSC and ATAR processes.

UAC calculates the NSW ATAR using scaled marks from 10 units of HSC courses. Scaling takes into account the academic achievement of students undertaking different courses, rather than simply awarding a fixed bonus to particular subjects.

Your position in a course and the scaled mean for that course influence your scaled mark.

This means you shouldn’t choose a Science subject simply because you believe it will automatically scale better.

You can read the explanation directly from UAC: How your ATAR is calculated.

What about university prerequisites?

University course requirements are a separate issue.

Some university degrees have subject prerequisites, while others list assumed knowledge or recommended studies.

For example, UNSW’s 2027 Domestic Undergraduate Student Guide lists Mathematics Extension 1 and Physics as assumed knowledge for its Bachelor of Engineering (Honours)/Bachelor of Engineering Science.

That is guidance for a particular university course and entry year. It is not a statewide NESA requirement to study those subjects.

The University of Sydney also distinguishes between the two terms:

• A prerequisite is a subject requirement that must be met for admission.
• Assumed knowledge is recommended preparation, but does not itself prevent you from receiving an offer.

If you’re choosing HSC subjects with university study in mind, check the requirements for your intended degree and admission year.

Useful starting points include:

• UAC Steps to Uni for Year 10 Students (2026)
• UNSW 2027 Domestic Undergraduate Student Guide
• University of Sydney: Prerequisites and assumed knowledge explained

08Questions and solutions

The following questions test whether you can distinguish the purpose of a depth study from its format, assessment, and syllabus requirements.

Question 1

A Physics student completes a 45-minute practical investigation using a worksheet provided by their teacher. They measure how the resistance of a wire changes with its length, record their results, and draw a graph.

Have they automatically completed a depth study?

Solution 1

No, not automatically.

The student has completed a practical investigation, but that doesn’t necessarily make it a depth study.

A depth study must be deliberately incorporated into the course as an investigation that develops scientific understanding and addresses the relevant syllabus requirements.

The practical could form part of a depth study if the teacher has designed it for that purpose and the required course time, skills, and knowledge outcomes are addressed.

The important distinction is that performing an experiment and completing a depth study are not automatically the same thing.

Question 2

A student studying Chemistry under the 2017 syllabus spends 15 hours on two related activities.

The first involves conducting an experiment on reaction rates. The second involves analysing published research on catalysts.

The student then presents their findings orally.

Must these activities be combined into one large written report to qualify as a depth study?

Solution 2

No. A depth study does not have to be one large written report.

Under the 2017 Chemistry syllabus, a depth study can consist of one investigation or a series of investigations and activities.

The two activities could form part of a depth study, provided the relevant requirements are satisfied.

These include:

• The 15-hour depth study allocation for that course year.
• At least one depth study in the relevant year.
• Questioning and Predicting and Communicating.
• At least two additional Working Scientifically skills outcomes.
• At least one Knowledge and Understanding outcome in each depth study.

An oral presentation can be an appropriate way to communicate findings.

The student still needs to meet the requirements of the particular task set by their teacher, but there is no universal NESA requirement that the final submission must be a lengthy written report.

Question 3

A student begins Year 11 Physics in 2027 and completes a 10-hour collaborative investigation using a computer simulation.

Their question investigates how changing the launch angle of a projectile affects its horizontal range.

They develop a prediction, analyse the simulation results, and connect their findings to a Physics focus area.

There is no physical experiment.

Can this count as a depth study?

Solution 3

Yes, it can.

The student is studying the new Physics 11-12 Syllabus (2025), which permits scientific investigations involving computer simulations and modelling.

The new course requires:

• 10 hours of depth studies in the Year 11 course.
• At least one depth study in Year 11.
• Working scientifically content from Questioning and Predicting.
• Content from at least one other focus area.

Depth studies can also be completed collaboratively.

There is no requirement for every depth study to involve a physical laboratory experiment.

What matters is that the investigation develops scientific understanding and satisfies the relevant syllabus requirements.

Question 4

A school tells its students that every NSW HSC Science student must submit a 2,000-word depth-study report worth 25% of their internal assessment mark.

Is this a statewide NESA requirement?

Solution 4

No. Neither the 2,000-word report format nor the 25% weighting is a universal NESA requirement.

NESA establishes the mandatory course requirements, while schools develop their own formal assessment programs.

Under the current ACE Rules, schools have authority to determine the number, type, and weighting of in-school assessment tasks, provided they follow the relevant course requirements.

A school may choose to assess a depth study through a written report, presentation, practical task, or another appropriate format.

Students should follow their own school’s assessment notification rather than assume that another school’s depth-study requirements will be identical.

There is also a distinction between the time allocated to completing a depth study and the percentage of a school assessment mark assigned to it. These are not interchangeable.

Question 5

Two students attend the same school and complete an identical 10-hour collaborative Physics investigation in 2027.

Both students investigate projectile motion using a computer simulation. Their investigation includes a research question, a prediction, an analysis of results, and a presentation.

However:

• Student A is in Year 11 and began Physics under the new 2025 syllabus in 2027.
• Student B is in Year 12 and began Physics under the 2017 syllabus in 2026.

Neither student has completed another depth study during the relevant course year.

Can the same investigation satisfy the depth study requirements for both students?

Solution 5

No. The investigation may satisfy the central requirements for Student A, but it does not satisfy the requirements for Student B as described.

The important issue is that the students are following different syllabus versions, even though they are studying Physics at the same school in the same calendar year.

Student A: Year 11 Physics under the 2025 syllabus

Student A needs at least one depth study in Year 11, with 10 hours allocated to depth studies.

The investigation includes:

• Questioning and Predicting.
• Content from a Physics focus area.
• A scientific investigation using a computer simulation.
• Collaborative work.

These features are consistent with the new syllabus requirements, assuming the investigation is appropriately incorporated into the course.

Student B: Year 12 Physics under the 2017 syllabus

Student B needs at least one depth study in Year 12, with a minimum of 15 hours allocated.

The 2017 syllabus also requires:

• Questioning and Predicting.
• Communicating.
• At least two additional Working Scientifically skills outcomes.
• Further development of at least one Knowledge and Understanding outcome in each depth study.

The proposed investigation only has 10 hours allocated and does not demonstrate all the required outcomes.

It therefore cannot satisfy Student B’s requirements as described.

The school could extend the investigation and incorporate the missing skills and knowledge outcomes, or provide additional activities to meet the requirements.

The important lesson is that the same scientific investigation can be suitable for different students, but its suitability depends on the syllabus each student is following.

This is particularly relevant during the transition to the new Science syllabuses, when Year 11 and Year 12 students may be studying different versions of the same subject.

Once you’ve confirmed which syllabus applies to your course, the next important decision is how to investigate your question. Choosing an appropriate experiment, simulation, fieldwork method, or secondary dataset determines what evidence you can collect and how convincingly you can explain your results. Those are the same scientific reasoning skills you’ll continue to develop throughout HSC Science.