Tag: HSC Science

HSC Sciences – improving performance in extended responses

Like it or hate it, the way HSC science subjects (e.g. Physics, Chemistry, Biology) are implemented in our HSC requires students not only to have quantitative skills for calculation-type questions, but also be skilled in forming cohesive arguments to support a conclusion – much like essays in English, but about scientific issues. Many students don’t have as much trouble with the quantitative aspects of HSC sciences, but have issues consolidating the qualitative aspects of their courses for essay-type responses.

Summarise essay dot-points that have extended response requirements

It is a good idea to know which parts of the syllabus correspond to essay-type exam responses. As you learn the course, always cross reference the content you cover with the syllabus. Become strongly familiar with the syllabus dot-points for each module. You will notice that most subsections in each module (i.e. the numbered sub-parts in each module) will have one or two dot-points that require ‘discuss’ or ‘assess’ or ‘evaluate’ – words which require students to be able to synthesise content and form coherent arguments.

Familiarise yourself with these dot-points. Revise related content, or ask your teacher / tutor about the relevant issues for each, then make a short summary sheet (probably half a page for each) in dot-point form to lay out everything that’s relevant.

Here’s a couple of examples of how you might roughly summarise the essay requirements for a sample module.

HSC Chemistry

The Acidic Environment

1. Summarise the industrial sources of SO2 and NOx and evaluate the reasons for concern about their release into the environment. For example: SO2 is from coal burning and car exhaust, and causes acid rain. NOx is from automobile exhaust mainly, (older cars, or malfunctioning catalytic converters) and causes photochemical smog, acid rain etc.

2. Trace the developments in understanding of acid / base reactions. E.g. understand the main developments in our definitions of acids / bases, outline the concept of conjugates, discuss the validity of current definition of acids / bases compared to past definitions.

3. Assess the use of neutralisation as a safety measure / to fix acid spills. E.g. outline what buffers are and how weak bases can be useful in neutralising acids. Understand why a weak base instead of a strong base is used. Explain neutralisation and buffer systems in terms of Le Chatelier’s principle.
HSC Physics

Space

1. Contribution of Tsiolkovsky, Obert, Goddard, Esnault-Pelterie, O’Neill, or von Braun to the development of space exploration (i.e. modern rocketry). E.g. Robert H. Goddard, considered as ‘father of modern rocketry’ developed the world’s first liquid-fuel rocket, pioneered research into multi-stage rockets (allowed astronauts to reach the moon), research into gyroscopic stabilisation, and steerable thrusters, allowing greater, safer control of rockets.

2. Discuss issues with safe reentry into Earth’s atmosphere. E.g. backward-facing astronauts (eyeball-in effect is less stressful than eyeball-out), radio blackout prevents communication to ground base during most of re-entry. Optimum angle of re-entry ensures probe does not skip off atmosphere, or undergo excessive deceleration and heating. Heat shields carry away heat. Parachutes are required for final deceleration, or in the case of a shuttle, gliding like a plane.

3. Describe, evaluate and interpret the MM experiment’s results. E.g. the MM experiment produced a null result for the existence of the aether. This result alone does not disprove the aether’s existence, but it does not contradict Einstein’s Theory of Special Relativity. The latter was developed further and was successful in predicting real-world phenomena, such as time dilation / length contraction observed between inertial frames with relative motion.

4. Discuss the relationship between theory and evidence supporting it, using Einstein’s predictions. E.g. Einstein’s thought experiments were merely conjectures supported by logical deduction – at the time, there was no experimental way to verify Einstein’s predictions. In modern times, with the advent of atomic clocks and space flight, we are able to experimentally verify Einstein’s predictions as correct. The relationship is theory of the unknown comes from deduction of what is known, and experimental verification follows. If real-world results differ, the theory must be modified or superseded. This is the scientific method.

Do this for the entire syllabus, by first identifying which syllabus dot-points require an extended response in order to be tested in an exam. These dot-points are guaranteed to come up in your exams, either in your first assessment, half yearly, HSC trials, or the external HSC exams. Don’t leave this till last minute – familiarise yourself as you go through the course, then revise and re-familiarise. Be sure to include all of the relevant issues, some of which are latent and require deeper analysis. E.g. is Ethanol truly greenhouse neutral? You can argue yes or no, depending on what evidence you include in your response.

Finally, don’t be afraid of those 6 mark or 7 mark discuss / evaluate / assess exam questions. As long as you’re familiar with most of the relevant issues that particular question entails, you will be fine. Good luck!

HSC Subject Selection

It’s almost that time of year again! Current year 10 students need to start thinking about what subjects to choose for next year. The choices they make now will affect their entire HSC, as the subjects they do in their Preliminary year will become their HSC subjects.

booktower

A look into HSC sciences

HSC chemistry and HSC physics are on the rise, with Physics gaining in scaled mean in 2008. The latest scaling statistics published by the UAC shows that both HSC physics and HSC chemistry are on the rise in terms of scaling. As per UAC Report (2008), HSC Chemistry and HSC Physics had a scaled mean of 31.6 and 30.4 respectively. Though Biology’s scaled mean remained unchanged since the previous year. Apart from this, HSC Chemistry and HSC Physics had a HSC mean mark of 37.5 and 36.7 respectively.

We have already mentioned the effects of HSC scaling and how these factors should play into your subject-selection decision. Ultimately we recommend students to choose subjects with at least a decent scaled mean (preferably 30+), that they also genuinely enjoy.

Students should seriously consider selecting HSC sciences for next year (apart from their generally high scaled means), particularly for students with a keen interest in science and a technically oriented mind.

In contrast to mathematics, HSC sciences provide an alternative experience to your HSC. For example, HSC maths is all purely theoretical, dealing with numbers, algebraic expressions, identities and theorems. In essence mathematics is the ‘pure science’. HSC sciences on the other hand offer a more practical perspective applied to real-world situations. This generally has come to mean that students find HSC sciences more of an involving, practical experience, learning about scientific concepts in a context that is applicable to real-world situations.

HSC Chemistry – a brief overview

For example, let’s look at a brief overview of what HSC Chemistry involves. In HSC Chemistry, much of the year 11 course is spent on establishing fundamental concepts such as the mole, the nature of basic materials (states of matter, bonding, inter/intramolecular forces, metals and water – to name a few) as well as ground rules regarding valency, periodic table trends and activity. Chemistry is a course that is heavily based on experience (as there are relatively little general rules or overarching principles to go by, as compared to HSC Physics) so it is important to establish a strong foundation of core principles early on.

In the year 12 course, the more fun aspects of the course begins to show. Many class periods will be spent on conducting experiments. A particular highlight would be titration experiments during the second module: The Acidic Environment, where students get to play with various indicators to observe interesting colour changes in their chemicals.

Other highlights of the course include learning about the industrial processes behind important chemicals in society, such as the production of ethanol, sulfuric acid (general acid), or sodium hydroxide (general base).

Apart from the chemistry behind processes and chemicals, students would also spend much of their time learning about the significance of these chemicals, their impacts on society as well as environmental issues that may arise.

One thing about the current syllabus for all HSC sciences is its emphasis on these ‘significance aspects’ on society and the environment. Some students (especially those who already have a strong grasp of the chemistry and the numbers) somewhat resent this requirement of the syllabus. However, there is value in requiring students to understand the wider implications surrounding the science taught. For example, it is satisfying and useful to know how a lead-acid battery works in terms of chemistry, but also be able to describe its negative environmental issues as compared to modern cells like a Lithium-ion or Vanadium-redox cell. Similarly, much of the surrounding aspects of HSC chemistry will become fully appreciated as students grasp the content beyond the mere core scientific principles.

 
 

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