1. GCE AS/A Level Biology
Practical Assessment

2. How can we best prepare for coursework?

3. Candidates need…. Practice at making observations
Practice at drawing biological material
Practice at preparing tables
Practice at drawing graphs
Practice at evaluations

4. Observations Detailed Start at the beginning
Record whole change (not just end result)
Record observation (not an interpretation)

5. Drawings Sharp pencil Single clear lines – ‘seamless’ joins
No shading (or colouring)
Informative title
Scale and/or magnification
Low power tissue plan (no cells)
High power cell detail
Cells to scale – no ‘bubble’ shaped cells
Invisible margin – drawing inside; labels outside
Don’t cross label lines

6. Tables Informative title One table
Independent or Input variable in left hand column
and dependent or output variable to right
Fully ruled, including a border….with a ruler
Column headings. Make sure dependent title covers the repeats and mean columns.
Units in headings
SI units
Observations in sequence, no conclusions inferences or ticks!
All cells completed
Usually no processed data (mean is ok)

7. Graphs Meaningful title – ‘A graph to show….’
Independent or input variable on horizontal x-axis
Dependent or output variable on vertical y-axis
Axes labelled
Axes with units
Full use of paper provided
Plotted accurately (use a x)
Straight lines between points unless certain intermediate values would fall on a curve

8. Students need to understand the key terms.
Accuracy
Anomalous
Reliability
Precision
Validity
Limitation

9. Students need to understand the key terms.
Accuracy

10. Accuracy
How close a reading or observation or measurement comes to the ‘true’ (or real) value or outcome.
This could refer to:
accuracy of measuring apparatus
closeness of data points to a line of best fit

11. Students need to understand the key terms.
Accuracy
Anomalous

12. Anomalous
an individual result or piece of data that does not match the trend shown by other results.
if this result, after repeats, still appears to be ‘odd’ (as it does not match the repeats) then it should be considered to be anomalous.
but what if the repeats are consistent with the original result?

13. Students need to understand the key terms.
Accuracy
Anomalous
Reliability

14. Reliability
a result or data may not always match the trend shown by other results.
the reliability of this data can be measured by carrying out repeats and/or statistical tests (such as the mean or standard deviation).
if an ‘odd’ result is confirmed to be sound by repeats, then it is not anomalous.

15. Students need to understand the key terms.
Accuracy
Anomalous
Reliability
Precision

16. Precision
measurements or observations can vary in how exact or clearly stated they are (i.e. how precise they are).
it could also refer to the number of decimal places that a number is expressed in.
The size of the smallest scale division on the measuring device. (or half the smallest division)

17. Students need to understand the key terms.
Accuracy
Anomalous
Reliability
Precision
Validity

18. Validity
results, measurements or procedures vary in how well they actually measure or carry out what they are designed to do.
inappropriate measurements or procedures could lead to conclusions that are not valid because they have not done what they set out to do.
factors or variables that have not been controlled will also affect validity.

19. Students need to understand the key terms.
Accuracy
Anomalous
Reliability
Precision
Validity
Limitation

20. Limitation
Any factor or variable that has not been considered or has not been controlled

21. Evaluation of procedure
Sufficient repeats to make results reliable
Sufficient range of input variable
Sufficient number of readings at different inputs
Control of other variables
How to make the procedure more precise/valid/accurate/reliable

22. Evaluation of results Spotting a trend Identifying anomalous results
Accounting for anomalous results
Identifying unreliable means
Explaining a trend

23. Practical Assessment - Task 1
Qualitative Task – 10 marks
Perform the task competently, demonstrating skilful and safe practical techniques
Wear safety glasses, be organised, deal with spillages, rinse apparatus before re-use etc
Observe accurately
Record reliably
Organise observations
Explain observations
The qualitative task:Practically based
Typically microscopy
…..or test tube observations.
May require some conclusions
Out of 10

24. Where do candidates go wrong with observations?
Students may:
miss a series of observations and start their description too late (e.g. immobilised yeast)
not be sufficiently descriptive e.g. not record differences in reaction (simply whether or not a reaction occurred)
use the wrong term e.g. put ‘clear’ when they mean ‘colourless’
record conclusions/inferences rather than observations
record final colour when asked to record colour change
draw text book diagrams rather than what they can actually see

25. Practical Assessment - Task 2
Quantitative Task – 10 marks
Use apparatus competently and safely
Record accurate measurements
Record results to an appropriate degree of precision
Record reliably
Organise results
Analyse and interpret experimentally derived results to reach valid conclusions
The quantitative task: Practically based
Typically a timed enzyme experiment
More meaty - out of 1o

26. Where do candidates go wrong with tables?
Students may:
use the wrong format for a table
forget to put units in
put units in the body of the table
not identify independent (input) variable by putting it in the first column
not ‘rule up’ tables especially the borders
split tables

27. Where do candidates go wrong with graphs?
Students may:
draw the wrong type of graph
put axes the wrong way around
do not label axes
use inappropriate scales
do not give units or the units are incorrect
incorrect trend lines

28. Practical Assessment - Task 3
Evaluative Task – 20 marks
Process and interpret results, identifying anomalies and reaching valid conclusions
Use scientific knowledge and understanding to suggest explanations for trends or patterns
Assess the reliability and accuracy of an experimental task, identifying weaknesses in procedures
Identify and explain main limitations of data collection strategy and give reasons for simple improvements
Comment on reliability of the data and discuss the validity of the conclusions
This extends the quantitative task - analysis of collected data and experimental situation - will not require further data collection
Modifications need to be considered.
Likely to be harder than other two task types
Out of 20
Tasks and Mark schemes down loaded from interchange site. Practical skills handbook available – INSET support

29. Where do candidates go wrong with evaluations?
Students may:
fail to spot anomalous results
incorrectly identify anomalous results
be unable to suggest obvious improvements to the procedure
be unable to suggest how to control other variables e.g. they may say ‘use a better thermometer’ when they mean ‘use a thermostatic water bath’
be unable to suggest how to make the measurements more precise e.g. ‘use a stop watch’ rather than ‘time from…until…’