IB internal assessment Recording Data & Error Analysis

Tables of Results Check these basic things in your table: Raw Data from the Bunsen Burner experiment yellow flameroaring flame Time / minutesTemp / °C A Title for the Table Columns centred & gridlines Consistent precision in the recording of the results (eg same number of d.p.) Correct SI Units are with the title, not the numbers The whole table fits on the page

ADVANCED Tables Check these advanced aspects: Raw Data from the Bunsen Burner experiment Heating method Beaker heated using a yellow flame Beaker heated using a roaring flame Time after the start of the experiment / minutes +/- 1 second Temperature of the water in the beaker / °C +/- 0.5 °C All aspects of the labelling clearly describe the data Error analysis is given and is correct (see next slide) Error analysis explained in a footnote. Full details given in labels Note: Timing was accurate to +/-1s because thermometer reading was taken at exactly the moment when the second number changed. The stopwatches were accurate to +/- 0.01s but we could not use this level of precision with the method used.

Qualitative Data You must include some notes from the experiment which are simple non-numeric observations. Not errors… Eg - The colour change happened gradually, from pink to yellow. – there was a cloudy sediment in the enzyme solution, could this be a sign of the old age or the solution.

Error Analysis When you record data –you are expected to know how accurate your readings are. For example: –using an alcohol thermometer to record room temperature as 24°C is less accurate –than using a digital thermometer which records the same temperature at 23.6°C

Why is this example incomplete ?

This is a ‘complete’ raw data table I would recommend underlining the title too.

The accuracy of the measuring equipment A thermometer graduated in whole °C is accurate to +/- 0.5°C 24°C will only become 25°C when the temperature rises to 24.5°C, and it becomes 23°C only when the temperature falls below 23.5°C So 24°C could be any temperature from 23.5 to 24.5 °C. Thermometer diagram here showing the readings mentioned

Accuracy of the measuring equipment (advanced) Digital readings - accurate to +/- one of the smallest figure. Eg 3.45g would be +/-0.01g Ruler type scales – accurate to +/- half the smallest graduation. Eg 24°C is accurate to +/-0.5°C Exception - Rulers for length. Accurate to one of the smallest graduations, because there is an error at the zero end as well as the reading end.

Uncertainties in the use of the equipment Stopwatches are a perfect example of this. Imagine a reading « 04:45.00 » ie 4 minutes seconds. You could say that this was +/- 0.01seconds BUT –Your finger can’t stop the watch in less that 0.1 second –There is a reaction time between seeing the end point and stopping the watch. –A chemical colour change could take 3 seconds to completely change. SO the reality is that uncertainties of your readings are greater than the accuracy of the stopwatch.

Graphs Do a scatter graph showing all the raw data ( so you can see anomalous data) Put a trend line in the scatter graph (by hand with pencil and ruler is OK)

Processing the Data To help show the trands in data Biologists often calculate something. If you calculate something from the data (eg averages, standard deviation, rate of reaction) 1.Write a paragraph explaining why you are doing this calculation 2.Explain How you did the calculation 3.Give details of ONE example