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Practical Work

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Internal assessed coursework

The internally assessed (but externally moderated) coursework component of the IB is worth 24% of the final assessment.  The practical scheme of work PSOW acts as a summary of all the investigative activities carried out by the student.

Time allocation for the PSOW

High level students are required to spend 60 hours and standard level students 40 hours spread over the two year program.  [This includes the 10  hours that will be spent on the Group 4 Project.]

Assessment criteria

There are eight assessment criteria which are used to assess the work of both higher and standard level candidates.

Design (D)

Data collection (DCP)

Data collection & processing  (DCP)

Conclusion and evaluation (CE)

Manipulative skills (MS)

Personal skills (PS)

The performance for both high level and standard level is judged against these assessment criteria, each consisting of achievement levels 0 to 6.  Therefore there is no difference in the assessment between standard level and high level.


All your practical work that makes up your PSOW will be kept in individual folders that are not to leave the lab, in case they get lost and we have nothing to show the external moderators! 

It is essential that your PSOW folder does not go home with you.

It is essential that your PSOW folder does not go home with you.

It is essential that your PSOW folder does not go home with you.

It is essential that your PSOW folder does not go home with you.




                                                        The Standard Laboratory report



Laboratory write ups tend to vary from one educational establishment to the other, but a general pattern is found by comparing different laboratory reports, generally the expected format is one of: 

Title, Date and name of experimenter:  This needs no explanation.

 Aim:  This section should define the purpose of the investigation

 Hypothesis:  formulate a testable hypothesis and explain the hypothesis using scientific reasoning.

 Apparatus:  Usually a list of apparatus and a schematic showing how the apparatus fits together.

 Method:  identifies the relevant variables (dependent, independent, control) and explains how to manipulate them.

 Results:  Typically the results are given in a table and then as a graph where appropriate with error bars.

 Conclusion:  Put here what it is you have found.  This may just be a statement of a numerical value, or a simple statement that relates your results to your hypothesis.

 Evaluation:  evaluate the method commenting on its reliability and/or validity, suggesting improvements to the method and making suggestions for further inquiry when relevant.


Reliability: Refers to measurement of the data. This depends upon the selection of the measuring instrument, the precision and accuracy of the measurements, errors associated with the measurement, the size of the sample, the sampling techniques used, the number of readings.

Validity: Refers to the success of the method at measuring what the investigator wishes to measure. This includes factors such as the choice of the measuring instrument and whether this measures what it is supposed to measure, the conditions of the experiment, and variable manipulation (fair testing).


You are not constrained to use this format but it is one which has become familiar to many experimentalists as it does follow a logical path.  Whatever format you prefer to use, make sure it can be followed easily by somebody who is not conversant with your work!


*   IB Practical Assessment Checklist  *

 Planning (a).

Have I Clearly stated the problem or research question?

Made a prediction (hypothesis) which is related to the research question?

Explained why I have made this prediction/hypothesis?

Selected the variables that I think will affect my experiment?


Planning (b).

Have I Chosen appropriate apparatus and included a diagram of the set-up?

Made sure that my method controls all of the relevant variables?

Made sure the method allows for a good range data to be collected[1]? 


Data Processing and Presentation.

Have I Recorded the data accurately (including units and uncertainties)?

Clearly laid out the data so that it is easy to interpret?

Processed the data to produce results that help interpretation?

Included error analysis where necessary?

Presented the results effectively[2]? 


Conclusion and Evaluation. Have I Written a clear conclusion based on my interpretation of the data?

Explained how I reached my conclusion[3]?

Evaluated all aspects of my experiment to identify limitations, weaknesses and sources of error?

Made suggestions for improving the investigation in the light of my evaluation?  

[1] A minimum of 5 data points (excluding the origin) are needed.

[2] Line graphs with error bars for continuous variables, histograms for discrete variables.

[3] It may be possible to compare your conclusion with information in text books.