How Science Works
What is How Science Works?
How Science Works is:
a) an integral part of the new curriculum
b) based on requirements from QCA
c) outlined in the OCR specification as follows:
1 Use theories, models and ideas to develop and modify scientific explanations.
2 Use knowledge and understanding to pose scientific questions, define scientific problems, present scientific arguments and scientific ideas.
3 Use appropriate methodology, including ICT, to answer scientific questions and solve scientific problems.
4 Communicate information and ideas in appropriate ways using appropriate terminology.
5 Obtaining, analysing and evaluating data:
a Carry out experimental and investigative activities, including appropriate risk management, in a range of contexts.
b Analyse and interpret data to provide evidence, recognising correlations and causal relationships.
c Evaluate methodology, evidence and data, and resolve conflicting evidence.
6 Applications, implications and ethical considerations:
a Consider applications and implications of science and appreciate their associated benefits and risks.
b Consider ethical issues in the treatment of humans, other organisms and the environment.
7 Scientific knowledge in its social context:
a Appreciate the tentative nature of scientific knowledge.
b Appreciate the role of the scientific community in validating new knowledge and ensuring integrity.
c Appreciate the ways in which society uses science to inform decision making.
We hope that this document provides some help and support in addressing the new requirements in your teaching. You may already be reasonably familiar with How Science Works (HSW) from GCSE and AS but you should be aware that there are some differences between HSW at GCSE and at A level.
What HSW at A level is:
· building on – and a continuation of – experience at GCSE
· opportunities for more interesting or relevant ways of teaching and assessing the content
· scientifically rigorous – not just opinion
· formalising teaching approaches that have already been recognised as good practice.
What HSW at A level isn’t:
· additional content in the specification
· a prescribed set of contexts in which students will be examined (although some contexts are given in the specification, questions may be set in other contexts).
Teaching strategies
This section gives some ideas for how you can incorporate HSW into your classroom teaching. It isn’t intended as an exhaustive list, but we hope it will provide you with a starting point when planning your own teaching.
Since the specification presents HSW 1–4 and HSW 5–7 differently, we have handled this in two different sections below.
How Science Works Statements 1–4
HSW statements 1–4 are broadly covered in the learning outcomes within the specification, so no specific learning outcomes are given here; rather, we offer a few examples of how you might like to tackle HSW within your own teaching.
Table 1 HSW 1–4
HSW statement / Teaching strategiesHSW statement 1
Use theories, models and ideas to develop and modify scientific explanations. / · Give students cards containing the different ideas on the historical development of the structure of the benzene molecule and ask them to put these cards into the correct historical order – we are not sure that we have it correct even now!
· Students study the dynamic equilibrium model. Does it explain how equilibrium is affected by changes in temperature, concentration and pressure? Why was le Chatelier’s principle not le Chatelier’s law?
· Students build models of organic molecules and use them to explain mechanisms.
HSW statement 2
Use knowledge and understanding to pose scientific questions, define scientific problems, and present scientific arguments and scientific ideas. / · Students research and discuss the advantages and disadvantages of biodiesel as an alternative fuel.
· Chemists produce a lot of waste and therefore have a responsibility to develop sustainable methods of dealing with this waste. Give examples of how this has been (or could be) achieved. The disposal of plastics and polymers is one possible context.
· Give students one question card and one answer card. One student reads out their question. Whoever has the answer reads it out and then asks their question.
HSW statement 3
Use appropriate methodology, including ICT, to answer scientific questions and solve scientific problems. / · Give students – or get them to produce – spreadsheets to calculate pH from [H+] and vice versa. Extend to other examples.
· Students use Excel to produce concentration–time graphs with constant half-life.
HSW statement 4
Communicate information and ideas in appropriate ways using appropriate terminology. / · Students use molecular model kits (or balloons) to show the shapes of molecules.
· Students construct energy level diagrams for Hess’ law cycles.
How Science Works Statements 5–7
HSW statements 5–7 tend to be flagged within the specification, so below you will find a summary of all of these learning outcomes along with suggested teaching strategies for each one. This is not intended to be a prescribed list, but rather a set of ideas – you should find that the different strategies can be transferred easily to other learning outcomes.
Table 2 HSW 5–7
HSW statement from OCR specification / Teaching strategies / Student book linkHSW statements 1 and 7a
4.1.1a–b The development and acceptance of models for the structure of benzene / · Students research the historical development of the structure of benzene. The strengths and weaknesses of each model are discussed. / 1.1.1 Introduction to aromatic chemistry, 1.1.2 The structure of benzene and 1.1.3
The delocalised model of benzene
Weekly plan 1: Arenes 1
HSW statement 6b
4.1.3h Link between unsaturated and saturated fats and current concerns about heart disease and obesity / · Students collect labels from different foodstuffs to see how much information they give about the types and amounts of fats present.
· Research into current views about the health benefits and risks of different types and quantities of fat. / 1.1.15 Fats and oils – building triglycerides and 1.1.16 Triglycerides, diet and health
Weekly plan 5: Carboxylic acids and esters 2
HSW statement 7c
4.1.3i Use of biodiesel as a fuel to increase contribution to energy requirements from renewable fuels / · This could be a debate about the available alternatives when we run out of fossil fuels – students can represent different viewpoints such as nuclear, bio and renewable fuels. / 1.1.15 Fats and oils – building triglycerides and 1.1.16 Triglycerides, diet and health
Weekly plan 5: Carboxylic acids and esters 2
HSW statement 6b
4.2.2g Production of degradable polymers from renewable resources / · This is a rapidly developing field – get the students to use the Internet to find different biodegradable polymers, together with their advantages and disadvantages. / 1.2.6 Addition and condensation polymerisation
Weekly plan 8: Polyesters and amides
HSW statements 6a and 6b
4.2.3c–f Requirements for chiral drugs and medicines to minimise side effects, for economical reasons and to reduce risk to companies from litigation / · Look at common drug structures to identify chiral centres. Are the drugs they represent single optical isomers or racemic mixtures? Are there side effects? / 1.2.9 Organic synthesis of aromatic compounds
Weekly plan 9: Synthesis
HSW statements 3 and 7c
4.3.1h Use of GC-MS by society in modern analysis and the use of such evidence in courts / · Find out about the use of
GC-MS in forensic science (for example) and the acceptability of such evidence in criminal cases. / 1.3.4 Gas chromatography–mass spectrometry
Weekly plan 10: Chromatography
HSW statements 1 and 7a
5.1.1i Use of rate equations to predict and propose a reaction mechanism / · Give students rate and stoichiometric equations and ask them to suggest mechanisms. / 2.1.7 Rate-determining step
Weekly plan 16: Initial rates and rate-determining step
HSW statements 1 and 7a
5.2.1b–d Born–Haber cycle as a model for the determination of lattice enthalpies and in testing the ionic model of bonding / · Given appropriate data, students construct Born–Haber cycles to calculate lattice enthalpies.
· Why are the lattice enthalpies calculated from ionic charge and radii so different from those calculated from the Born–Haber cycle for silver halides? Why are they similar for sodium halides? / 2.2.1 Lattice enthalpy to 2.2.4 Further examples of Born–Haber cycles
Weekly plan 22: Lattice enthalpy 1
HSW statement 6a
5.2.3i–m Development of fuel cells as an alternative to direct use of finite oil-based fuels in cars compared with logistical problems of their development and use / · Research and presentations on fuel cells – to include the relevant chemistry as well as advantages and disadvantages and common misconceptions / 2.2.13 Storage and fuel cells and 2.2.14 Hydrogen for the future
Weekly plan 26: Fuel cells
HSW statements 7a and 7b
5.2.3n–p Political and social desire to move to a hydrogen economy has many obstacles, including ignorance that energy is needed to produce hydrogen and that fuel cells have a finite life. / · Write a letter to your local MP expressing your views as a chemist in response to a government leaflet describing fuel cells as: ‘Cheap, non-polluting, everlasting energy sources’. / 2.2.13 Storage and fuel cells and 2.2.14 Hydrogen for the future
Weekly plan 26: Fuel cells
Specific teaching examples
In this section, we take four of the sample learning outcomes from Table 2 and give more detail and ideas on planning and running such a lesson, including resource links.
Example 1: 4.1.3h Healthy fats
Learning outcomes
· Compare the link between trans fatty acids, the possible increase in bad cholesterol and the resultant increased risk of coronary heart disease and strokes.
Previous knowledge
· Knowledge of cis–trans isomerism from AS
· An understanding of healthy eating from PHSE/citizenship lessons
Introduction
· Revise E/Z and cis–trans isomerism.
· Brainstorm students’ knowledge of the importance of fats in a healthy diet and the dangers of some types and amounts of fat.
Tasks
· Students initially use the Internet to research the role of fats in our diet.
· Research should include saturated and unsaturated (and monounsaturated), as well as cis and trans.
· Students collect food labels and compare the quality of the data provided.
· Divide students into groups and ask them to produce a poster – based on chemistry – explaining to the public what they should be looking for on the labels of foodstuffs.
Links
· Read an online article: Differences in fatty acid intake
· Read this BBC Health article on cholesterol.
Example 2: 4.2.2g Degradable plastics
Learning outcomes
· Outline the role of chemists in minimising environmental waste by the development of degradable polymers, similar in structure to poly(lactic acid).
· Explain that condensation polymers:
o may be photodegradable as the C=O bond absorbs radiation
o may be hydrolysed at the ester or amide group.
Previous knowledge
· An appreciation of the problems caused by the disposal of (addition) polymers from GCSE and AS
Introduction
· Ask students what they remember about the disposal of plastics.
· Explain about condensation polymers and their hydrolysis.
Tasks
· Research the development of degradable polymers.
· Find out the structures of some degradable polymers.
· What are they used for?
· How do they degrade?
· Either use molecular model kits to demonstrate your degradation or produce a PowerPoint presentation.
Links
· Research bio plastics on the internet
· Read ‘The A to Z of materials’ online and research the development of degradable plastics
Example 3: 5.11i Rate equations and mechanisms
Learning outcomes
· For a multi-step reaction:
o Propose a rate equation that is consistent with the rate-determining step.
o Propose steps in a reaction mechanism from the rate equation and the balanced equation for the overall reaction.
Previous knowledge
· Knowledge of rate equations and stoichiometric equations
Introduction
· Give students rate equations and stoichiometric equations for suitable reactions – there are many such examples on OCR Unifying Concept papers from the previous specification.
Tasks
· Students have to produce suggested mechanisms from the data given above. (There are usually several possible mechanisms, but some more probable than others! It is not possible to say that a suggested mechanism is correct, but it is possible to say that one is incorrect.)
Links
· Online tutorial: Introducing chemical kinetics
· Online tutorial: Rates of reaction
· Go online for links to experiments and graphs to determine orders of reaction.
Example 4: 5.2.3i-p Development of fuel cells
Learning outcomes
· To understand the chemistry behind fuel cells
· To understand the benefits and drawbacks of fuel cells
· To realise the limitations of fuel cells, despite the political and social desire to move to a hydrogen economy
Previous knowledge
· Almost certainly, none
Introduction
· Ask students to find out about fuel cells. They might need a worksheet guiding them towards the things that they should be considering, as well as some possible sources of information.
Tasks
· Divide students into groups, each group has to produce a presentation on fuel cells – tasks can be divided amongst different groups, or each group can prepare their presentation for a different, specified audience.
Links
· Go online for information about producing hydrogen for the US Department of Energy.
· Research how fuel cells work, their benefits and their efficiency.
· Look online for industry news and information about fuel cell technology.
How might How Science Works appear in exam questions?
In the examination papers, HSW is likely to appear in a range of contexts. In fact, many questions will contain some aspects of HSW. Each examination paper is expected to contain questions that address each of the seven HSW statements.
This may seem a lot of HSW but it can be incorporated very easily. For example, a question about bonding covers HSW 1 as it involves the dot-and-cross model of atomic structure. Any question that expects a scientific explanation will cover HSW 2 and 4. HSW statements 1–4 can easily be assessed in this way.
There will, however, be certain questions or part-questions that are designed to assess HSW. These can be recognised as they are likely to assess the HSW statements 5–7 (see Table 2). You may wish to write your own questions that test certain aspects of HSW based on the practical work carried out by your class. This should be relatively straightforward.