Applied Science BTEC Nationals/Scientific Investigation

Content

On completion of this unit a learner should:

1. Be able to plan an investigation relevant to the area of study

2. Be able to undertake the planned investigation, using appropriate scientific principles

3. Be able to collect, collate and analyse the results from the investigation

4. Be able to draw conclusions from the investigation.

Assignment 1 - Planning

Scenario

Catalase is an enzyme which catalyses the breakdown of hydrogen peroxide to water and oxygen. It is present in most living organisms. Different organisms have different versions of the enzyme. We can use a suspension of yeast cells as ‘the enzyme’ although obviously this is not very pure. Alternatively we can use homogenised liver, parsley, etc.

As a class, we will look at various aspects of this enzyme. We will compile a book which gives a comprehensive description of catalase. You will provide one chapter to the book.

Note: Approaching the assignments in this way covers multiple Key Skills. In particular, the assignments are designed to cover the outer key skills (Working With Others, Problem Solving and Improving Own Learning and Performance) at level 2 - hence the frequent instructions to work as a team and the inclusion of a conference (which students are expected to organise for themselves). If key skills are not a priority, then these aspects can be tackled in a less involved manner.

Aspects we could include:

• Methods of following reaction – volume of oxygen, loss of mass, etc.
• Comparison of enzyme levels from the same sample over time: Use as assay for time of death
• Comparison of enzyme levels and properties from different species (e.g. yeast, liver, parsley)
• Comparison of enzyme levels from the same species at different stages in its life cycle (e.g. green, yellow, red peppers)
• Comparison of enzyme levels from different parts of the same organism
• Extraction of the enzyme from homogenised biological material
• Effect of temperature
• Effect of pH
• Effect of inhibitors
• Effect of peroxide concentration

Task 1– Choosing a topic and researching it.

Decide what aspect of the enzyme you want to work on. Share this information with the others in the class. Are there any areas the class has failed to address? Who will tackle these areas?

What is the nature of the investigation?

State your objectives and hypothesis

Describe what type of experimental research you need to do (e.g. laboratory)

There is a lot of basic research to do, which will be common to many research topics. Make a list of what research you need to do. Share this information with the rest of the class. Who else is looking for the same information? Make arrangements to share out the task of research equitably.

What deadline will you need to set for completion of sharing research? This will need to be before the deadline for this assignment!

Break down your research targets into short deadlines. How will you find this information? Will you need help using any of these resources?

Information resources:

What information sources will you need?

• Consider textbooks, internet sources, the college’s subscription sources, BRENDA database, contact with relevant academics.

How will you extract information from them?

• Make headings based on what you need to know, and sort the information into these categories as you do your research.

How will you record the sources?

• Use the Harvard referencing system. Note the relevant information as you go along: Author, date, title, publication/web address

Assess if the information is reliable and applies to your investigation.

• Wikipedia is notoriously unreliable – how would you check that its contents are correct?

Meets criterion P1

Task 2 – Evaluating the research.

Collect all the relevant research material – yours and other students’.

List the problems you need to solve to answer your research targets.

Do you now have all the information you need? How valuable is the research done so far? (Assess each piece of information)

Do you need more information? If so, how and when are you going to get it?

Meets criterion M1

Task 3 – Planning the investigation.

List the aims of your investigation – how you will know how the investigation has succeeded? What is your hypothesis?

Consider options for tackling the research. Give advantages and disadvantages. Consider what resources will be required and any costs.

Describe the details of experimental design and controls, the proposed analytical techniques to be used, your assessment of possible errors in practical work.

Justify the hypothesis, experimental procedures and recording methods chosen. Confirm your decision with the lecturer.

Produce a detailed plan for your investigation, including health and safety assessments.

Health and safety risk assessments should include descriptions of how you will eliminate/minimise any identified risks;

Meets criteria P1 and D1

Assignment 2 - The practical investigation

Scenario

Having researched and planned an investigation into one aspect of the enzyme catalase, you now have the chance to carry out the practical work. Your initial findings will be reported to the rest of the class at a science conference. Your final report will form a chapter of the class’s book about catalase.

Task 1 – The practical investigation.

Having scientifically planned your investigation, it is time to apply those principles by doing the experimental work.

You will need to show that you can:

• Assemble the relevant equipment and materials;
• Adhere to health and safety requirements;
• Manipulate and observe experiments skillfully
• Use appropriately the instruments and techniques for taking measurements;
• Record results with accuracy, integrity, precision;
• Maintain a working laboratory book

Your records should include:

• health and safety issues
• what support you rely on
• how you cooperate with others
• how you revise your plan as you go along

The experiments will carry on after the conference which is the main focus of assignment 3. After the conference there will be time to adapt your work based on the ideas and suggestions from the meeting.

Meets criteria P2 and P3 (‘practical’ part)

Assignment 3 - Reviewing progress

During your work on assignment 2, you will be attending a science conference to review your progress.

Scientists regularly meet to discuss their latest progress. Conferences are less formal than publishing a research paper. Papers need to be peer-reviewed before publication. Presentations at a conference are not reviewed beforehand and the audience is expected to provide constructive criticism and suggestions.

You will present your findings so far to the rest of the class. They will help you review your progress and may use some of your ideas in their own research.

There are two forms of presentation at a conference:

Short lectures

The progress of the research is briefly described and the audience is invited to comment.

Posters

Information about the research is assembled to make a display. Other researchers can read the work at their leisure and question the researchers about their work.

This assignment is based largely on the information exchanged at the conference.

Task 1 – The conference.

Prepare a poster and/or presentation about your work so far.

Describe how you ensure accuracy and precision in your work.

Evaluate how effective these measures have been in making your work accurate and precise.

Meets criteria M2 and D2 (‘evaluation’ part)

Task 2 – Review.

Write a summary of what you have learned from the conference:

1. What have you learned about your own work? Could you improve the techniques or are you justified in repeating the same methods?
2. How is the rest of the class progressing? If anyone is doing better than you in any respect – how can you learn from their methods? If anyone is failing to meet their targets is there any way you can help them (without jeopardising your own work)?
3. Discuss how the collaboration is working and what problems have occurred. Describe how the work has met or will meet its targets. Include your contributions. Suggest and agree ways to improve.

Meets criterion M3

Task 3 – The practical investigation.

Discuss possible ways to improve the accuracy and precision of your methods.

Analyse how effective each improvement would be.

Justify whether you adopt or reject each improvement.

Meets criterion D2 (‘improvements’ part)

Assignment 4 - Data analysis

Scenario

As you collect more and more raw data, it becomes important to analyse the results. You might find that one measurement is obviously wrong, and needs to be repeated. You can check your results with those of the rest of the class, and with the studies you researched in Assignment 1, but you will need to convert your results into the same format as the other values.

Task 1 – Data analysis.

This work is best done as we go along, but towards the end of the investigation you need to make sure that you can make sense of all the data collected.

Collect your data into tables and graphs. Take care to show:

• organisation of data e.g. class intervals, tallying;
• correct units of experimental quantities used;
• fitness for purpose of methods used;
• repeatability;
• sources and magnitudes of errors in reading taken
• assessment of experimental accuracy and precision;

What do your data show you? You need to process and analyse the raw data e.g. mean, standard deviation, student’s t-test. Particularly useful is establishing that two results are significantly different. Make sure your calculations are accurate.

It will be useful to compare your results with any values you can find in published studies. Assess the information sources you use:

• is the source relevant?
• if so, does it support or contradict your results?

Meets criteria P3 (‘analysis’ part) and D3

Assignment 5 - Writing your report

Scenario

It is time to start writing your chapter of the class’s book on catalase.

There is a lot you can write already – based on your initial literature research.

As you collect and analyse more data, your conclusions and contribution will become more and more substantial.

Having done all the hard work, give your efforts the report they deserve!

Task 1– Writing your final report.

Write your scientific report of the investigation:

• Use correct scientific protocol i.e. structure, format;
• Use correct scientific language and terminology i.e. past passive tense;
• Include a section for relevant references and bibliography;
• Present your data in an appropriate format, to an appropriate degree of precision, and using correct units.

Meets criterion P4

Task 2 – Conclusions.

Read over your conclusions again.

• How are they justified?
• What experimental data supports your conclusions? Do any of your experiments contradict your conclusions; and if so, why have you ignored these results?
• How do your conclusions relate to the reports you researched in Assignment 1?

Meets criterion M4

Task 3 – Final evaluation.

In conclusion, your report should include:

• An evaluation of the results.
• A discussion of sources of error and how to minimize them.
• Evaluation of your conclusions – how certain are they?
• Comparison of your experimental methods and literature investigations.
• Consideration of your hypothesis – did it hold up?

Meets criterion D4

Resources

Edexcel recommend the following resources apart from * which have been added to edexcel's list.

Textbooks

Coyne G S — The Laboratory Companion: A Practical Guide to Materials, Equipment and Technique (John Wiley & Sons, 2005) ISBN 0471780863

Dean J R et al. — Practical Skills in Chemistry (Prentice Hall, 2001) ISBN 013028002X

Dean J R et al. — Practical Skills in Forensic Science (Prentice Hall, 2005) ISBN 0131144006

Derenzo S E — Practical Interfacing in the Laboratory: Using a PC for Instrumentation, Data Analysis and Control (Cambridge University Press, 2003) ISBN 0521815274

Hutchings K — Classic Chemistry Experiments (The Royal Society of Chemistry, 2000) ISBN 0854049193

Jones A et al. — Practical Skills in Biology, 3rd Edition (Prentice Hall, 2002) ISBN 013045141X

Lintern M — Laboratory Skills for Science and Medicine: An Introduction (Radcliffe Medical Press, 2006) ISBN 1846190169

Morgan S — Advanced Level Practical Work for Biology (Hodder Murray, 2002) ISBN 0340847123

Prichard E and Lawn R — Practical Laboratory Skills Training Guide: Measurement of pH (The Royal Society of Chemistry, 2003) ISBN 0854044736

Prichard E and Lawn R — Practical Laboratory Skills Training Guide: Measurement of Volume (The Royal Society of Chemistry, 2003) ISBN 085404468X

Reed R et al. — Practical Skills in Biomolecular Science (Prentice Hall, 2003) ISBN 0130451428

Journals

Nature

New Scientist

Websites

Ideas for practical investigations.

*BRENDA enzyme database entry for catalase