How Science Works
What is How Science Works at A Level?
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 but you should be aware that there are some differences between HSW at GCSE and at A Level.
What HSW at A Level is:
a) building on and a continuation of experience at GCSE
b) opportunities for more interesting or relevant ways of teaching and assessing the content
c) scientifically rigorous – not just opinion
d) formalising teaching approaches that have already been recognised as good practice.
What HSW at A Level isn’t:
a) additional content in the specification
b) 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 incorporating 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 you plan your own teaching.
Since the specification presents HSW 1–4 and HSW 5–7 differently, we have handled this in two different sections.
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. / · Students are given cards containing the different ideas on the historical development of the atomic structure and asked to put them into the correct historical order – we are not sure that we have it correct even now!
· Mention the dual wave–particle theory for the electron.
· Students build models of atomic structure and use dot-and-cross diagrams for bonding.
HSW statement 2
Use knowledge and understanding to pose scientific questions, define scientific problems, and present scientific arguments and scientific ideas. / · Students discuss global warming and the opposing opinions amongst chemists as to whether human activity is responsible.
· Students are given 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. / · Students are given spreadsheets to calculate relative atomic masses or percentage yields from appropriate data.
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 use dot-and-cross diagrams for bonding and 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 easily be transferred to other learning outcomes.
Table 2 HSW 5–7
HSW statement from OCR specification / Teaching strategies / Student book linkHSW statement 7a
1.1.1a–e Modern development of the structure of the atom; the changing accepted view of the structure of the atom; acceptance (and rejection) of different theories for the structure of the atom from the Greeks, Dalton, Thompson and Rutherford, Moseley et al. / · Students individually research the contribution of different scientists.
· They then present their arguments in an historical context in a class debate.
· The students should appreciate that each advance overcomes problems in the previous model. / 1.1.1 The changing atom
HSW statement 7a
1.2.1d–h Modern development of the structure of the atom / · Again, students individually research the contribution of different scientists and present their arguments in an historical context in a class debate.
· As before, the students should appreciate that each advance overcomes problems in the previous model. / 1.2.1 The evidence for shells
HSW statements 7a and 7b
1.3.1a-c Development of the Periodic Table from Döbereiner, Newlands, Mendeléev, Moseley,
Seaborg et al. / · Groups of students research the contribution of one chemist and present their findings to the rest of the class in historical order. / 1.3.1 The Periodic Table: searching for order
1.3.2: Mendeléev and beyond
HSW statements 6a and 6b
1.3.3.f Health benefits of chlorine use in water; ethical implications of adding chlorine to public water supplies (also fluorine in drinking water) / · Students visit a local waterworks, with a suitable arranged talk.
· A class debate in which the students are split into two groups – one supporting chlorination (or fluoridation) of drinking water, the other against.
· Discuss: ‘Do we have the moral right to make decisions about the health of other people?’ / 1.3.9 Group 7 elements: uses and halide tests
HSW statements 6a and 7c
2.1.1i Benefits to society of a high atom economy (see also sustainability: Unit F322: 2.4.2) / · Students research atom economy and the other factors that make industrial processes sustainable.
· They present their findings via PowerPoint. / 2.2.9 Atom economy
HSW statement 6b
2.1.2g Toxicity from CO production during incomplete combustion of fuels / · Students make posters or collages using articles from the media emphasising the importance of testing gas appliances for CO emission. / 2.1.10 Hydrocarbons as fuels
HSW statements 6a and 7b
2.1.2j Desirability of renewable fuels for rich countries may lead to problems of food supply for countries supplying the crops needed for the fuel. / · Students research and debate the pros and cons of using renewable fuels.
· Students are surprised that there are cons. / 2.1.11 Fossil fuels and fuels of the future
HSW statements 6a, 6b and 7c
2.1.3.k Benefits from the processing of alkenes to produce polymers and plastics; drawbacks from waste polymers. Increased political and social desire to reduce plastic waste, to recycle or to use for energy production. Developments of new degradable plastics produced from renewable resources. / · Students role-play members of a local council and debate its policy for waste plastics.
· The students represent councillors, scientists giving expert evidence and local environmental groups. / 2.1.18 Polymer chemistry
2.1.19 Polymers – dealing with our waste
2.1.20 Other uses of polymer waste
HSW statements 6a, 6b, 7a, 7b and 7c
2.2.2f Initial use of CFCs as harmless aerosol propellants offset when scientists discovered that CFCs damaged the ozone layer. This provided important evidence that enabled international action to reduce and phase out CFC use and has led to development of ozone-friendly alternatives and natural repair of the ozone layer. / · Students research into why CFCs were used and how their damage to the ozone layer was unexpected.
· They make predictions as to what will happen in the future via a presentation.
· Different members of the group are responsible for different aspects. / 2.2.7 Halogenoalkanes and the environment
HSW statement 7c
2.2.3c Use of analytical techniques to inform decision making, e.g. breathalysers in drink-driving cases / · Carry out a class practical to show the effect of ethanol on potassium dichromate (risk assessment).
· Explain that nowadays infrared spectroscopy is used.
· The students discuss if this application of chemistry benefits society or represents an invasion of an individual’s liberty. / 2.2.10 Infrared spectroscopy
HSW statement 6a
2.3.2d and i Benefits of catalysis in terms of possible lower production costs; however, also implications for their disposal (toxicity) / · Students research why catalysts are good for industry and for the environment.
· Next they find out if there are any problems associated with catalysts.
· Students present their findings in a class discussion. / 2.3.11 and 2.3.12 Catalysts 1 and 2
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: 1.1.1a-e The development of the structure of the atom
Learning outcomes
· To understand that scientists put forward models to explain observed facts
· To understand that when certain facts cannot be explained by the current model, then a new model must be developed
· To understand that even the models we use today may be reviewed in the light of new data
Previous knowledge
An understanding of the modern ideas about atomic structure from GCSE
Introduction
· Make students aware that scientists don’t get it right at the first attempt.
· Explain that if an existing model cannot accommodate new data, then a new model has to be developed.
· Outline that any new model has to explain all known facts.
· Describe how this cycle continues and that even today there are data that cannot be explained by the present model for atomic structure and that scientists are continuously modifying this model.
Tasks
· Students are given – or research – the names of famous atomists (see 1.1.1).
· They then research these atomists’ contributions to our understanding of the structure of the atom.
· Finally, they role-play the atomists and explain and defend their contribution.
Links
· History of Science: Famous scientists. Start here to search the web for Democritus; Thomson; Bohr; Broglie; Schroedinger and Heisenberg.
Example 2: 2.1.1i Atom economy
Learning outcomes
· To understand the meaning of the term atom economy
· To be able to calculate atom economies
· To realise that a high atom economy means less waste
· To understand that atom economy is only one factor in determining the sustainability of an industrial process
Previous knowledge
· The idea of atom economy at GCSE, although probably as a qualitative rather than a quantitative idea
· An understanding of other concepts such as carbon neutrality and global warming
Introduction and tasks
· Introduce students to the idea of atom economy if they have not met it before.
· Explain how to calculate atom economy.
Tasks
· Students are given some industrial processes to look at, such as the Haber process, the contact process, the manufacture of nitric acid, etc. They can find more examples by themselves, for example in textbooks or on the Internet.
· They then use the equation to calculate the atom economy.
· Next, they are asked to check if it is an overall equation:
1. There could be reactions necessary to obtain the starting materials, as is the case in the formation of hydrogen from natural gas in the Haber process.
2. There could also be the burning of fossil fuels to provide the energy for the process, forming waste carbon dioxide (global warming) and water vapour.
· Students also consider the production of ethanol from either ethene and from sugar. The former has a 100% atom economy, whereas the latter involves removal of carbon dioxide from the atmosphere by photosynthesis. Which is better for the environment?
· Students then debate the importance of atom economy to sustainable development.
Links
· RSC: Atom economy. Explanation and examples of green chemistry
· Campaign: Zero Waste Alliance. Find case study examples of how industry is reducing waste
Example 3: 1.3.3f Should chlorine (and fluoride) be added to our drinking water?
Learning outcomes
· To understand why chlorine (and fluoride) is added to our drinking water
· To understand that adding chemicals to our water has moral and ethical implications
Previous knowledge
The use of chlorine to kill germs in our drinking water (and in swimming pools), but not the moral and ethical implications
Introduction
· Arrange a visit to a water treatment works with a suitable talk from an engineer. Alternatively, ask the students to research which chemicals are used to treat our drinking water and why. Ask them specifically to find out what happens to drinking water.
Tasks
· Students undertake a debate whereby the class is divided into two – one group supporting and the other opposing the addition of chlorine (or fluoride) to our drinking water.
· They are given 10 minutes to decide upon their arguments.
· Two students from each group are elected as speakers and talk for five minutes each.
· After the presentations, each group is given five minutes to cross-examine the other.
· Issues should include:
1. the other uses of chlorine (e.g. bleach) and fluoride (e.g. rat poison)
2. the dangers of diseases such as typhoid and cholera
3. the increased risk of tooth decay