Conclusion /Evaluation (CE)

1. Conclusion/Evaluation (CE)

2. Section 3:Conclusion and Evaluation

3. Organisation of Conclusion and Evaluation • Conclusion – clear, simple, precise statement (s) • Explanation of conclusion • Evaluation of results • Evaluation of the procedure

4. Conclusion The concentration of sucrose affects the rate of osmosis across eggs The rate of osmosis into a chicken (Gallus Gallus) egg is affected by the concentration of sucrose in which it is immersed. The rate of osmosis into the egg is least at 1 M sucrose, and increases as sucrose concentration decreases from 1 M to 0.2 M.

5. Explanation of conclusion • Explain briefly how your graphs and statistical analysis support your conclusion • Provide references support fro the scientific literature to support your conclusion • Refer to your hypothesis (if you made one) and state if it has been supported or refuted

6. Critical evaluation of the results • How reliable is the data? • Do the repeats support each other? • Are any uncertainties large enough to have a significant effect? • How large is the standard deviation? • Can you draw a good line of best fit, or are there alternative lines of best fit? • Does the graph match your hypothesis? • Explain the results of any statistical analysis

7. Critical evaluation of the results (2) • EXPLAIN your critical evaluation of the data • Use p. 34 – 35 of your book for inspiration

8. Critical evaluation of the procedure You must use the words ‘accuracy’ and ‘reliability’ Accuracy: correct and careful use of the best available apparatus Reliability: Having enough data to be able to process it fully and draw firm conclusions Identify at least 3 clear weaknesses and provide a realistic improvement for each Identify the weakness and suggest the improvement before going on to the next weakness The weakness commonly involves equipment OR methodology

9. Conclusion From the graph, we can deduce that the surface area to volume ratio has a strongpositive correlation to the degree of penetration. The points lie on a curve of best fit that plateaus near the end. • Too vague, data not used • No justification

10. Conclusion correction • Add data The points lie on a curve of best fit that plateaus after the Surface area/Volume ratio reaches 7. Use of data

11. Conclusion correction Research quote, correctly referenced “student background information diffusion, osmosis and cell membranes” biology.arizona.edu, last accessed16.10.200813.15. Use of research

12. Experimental error (example)

13. Evaluation The errors are not sufficiently large to affect the line of best fit. However, the operator error in cutting the blocks and reaction time when using the stopwatch………. No figures, improvements

14. Evaluation The uncertainty value of 5.56% is acceptable and theallows a curve of best fit within the error bars. The operator error in cutting the blocks increases personal uncertainty, this could have been improved by using blocks cast in different sizes instead of cutting Suggested improvement

15. Uncertainty processing • Uncertainty processing is not required but can be done • Uncertainties must be listed in the data and evaluated in terms of their effect on the results and how they could be minimised. • Uncertainty calculations are not required, but the simplest method is to calculate a percentage uncertainty by uncertainty of instrument used • Maximum uncertainty is the uncertainty divided by the smallest measurement • Mean uncertainty is the uncertainty divided by the mean measurement

16. Uncertainty calculation example Length: ±0.5mm (systematic) Maximum uncertainty: 0.5 mm/9mm x 100% = 5.56% Mean uncertainty = 0.5/15 x 100% = 3.33% Time: ±0.005s (absolute) Uncertainty: 0.005s/600s x 100% = 0.001% Total maximum uncertainty = 5.56%