To make sure you have addressed all the aspects appropriately, self-assess your work using the checklist on your coversheet.

MrT’s Design Tips:

Take advantage of ‘play time’ to test the equipment and to feel the investigation. It will help you identify variables to be controlled and to determine a good range of values for the IV.

Clear, Concise, Precise

Include all the relevant information in a succinct manner. Use tables to organise your thinking and make sure that all units and uncertainties are completely and correctly presented – this might take some fiddling with Word formatting.

Think carefully about how you will use the data – design backwards!

• What kind of data do you need to collect to address the RQ?
• Can these be measured directly or do calculations need to be carried out?
• What type of graph do you want to use? Why?
• What statistical test is most appropriate? Why?
• What range and increments of the IV will address the RQ?
• How many repeats do you need to carry out at each point?

Now you know all this, you can design your results table – and then the method will follow easily as you note everything you need to do to fill the table.

Method for controlling the variables is not just about the controlled variables!

- Exactly how are you manipulating the IV and what are its values?

- Exactly how are you recording the results, including uncertainties

- Exactly how are you keeping all other variables controlled? State how each might affect the results if not controlled and the method and units for controlling each one. (e.g. Substrate concentration -higher concentrations lead to faster reaction rates as there are more molecules for reactions. Use a stock solution of 1M for all investigations, prepared by the lab technician.)

For some more tips on Design, visit these websites:

IA Design, from the Triple A Learning IB Biology Blog

The Design criterion, from the IB Biology Teachers Support Material page.