Evaluation

Key components

Evaluate the method by identify any issues of reliability

Identify the type of error and explain the impact the relative impact on the experimental data of the issue (This will be for grade 10 only)

Identify improvements related to issues and explain the related justification

This can be effectively shown in a table (the impact is only needed in grade 9 and 10):

Sentence starters

A source of error may have been….

This would have affected my results because….

Another source of error was…..

It would have affected my results because….

If I could do this again, I would….

I could improve the method by ....

I would make these improvements because...

This investigation has made me think of a new question, which is...

I could test this by...

I would like to find out more about ... because...

Example

There were several sources of error throughout the experiment.

The thermometer was not calibrated and measured the temperature of boiling water to be 99⁰C, meaning that all temperature measurements were off by 1⁰C. This represents a systematic error.

As regards the controlled variable, there were two sources of random error. Rather than using a graduated cylinder to measure the volume of the hot water, a beaker was used. The beaker has a considerably larger uncertainty, meaning that the volume of the hot water is not known very precisely. Since the volume of the water affects the rate of cooling, this could have had an effect on the final outcome.

Secondly, it was assumed that the ice cubes would have the same mass. However, the ice cubes varied in size.

Despite these errors, however, the data could be considered to be reliable. Multiple trials were conducted with very little variability in the results.

In light of the errors suggested above, there are several improvements that could be made to the method.

The thermometer error could have been improved by using a properly calibrated thermometer. Using a temperature probe, rather than a thermometer, would also have allowed for greater precision.

The random errors could have been reduced by using a graduated cylinder to measure the volume of the hot water and by measuring the mass of the ice cubes, rather than the number of ice cubes.