It is advised that the results should be brought together from each group outside lesson time, to give one picture along the transect to analyse. This may not be possible if individual investigations have been carried out. Alternatively, pupils can produce their own presentations of their data as a follow-up from the data collection activity, and these can be discussed and evaluated by the class.
The sites/ trees used may be different between the groups but a spread of data along the transect should be extracted. (The only way to know if groups use exactly the same tree is if GPS is available, to log coordinates at each station, or the trees are labelled prior to the session).
The data can be put into a spreadsheet to be analysed or can be plotted in a graph by hand having distance from road along the x-axis and average percentage of particulates along the y-axis see exemplar materials in field materials folder. Sound could be also place on the opposing y-axis. Analysis worksheet could be used as prompts for the pupils to analysis the data and consider the social/ environmental aspect.
The sticky tape on the slides can be examined under the microscope. Make mini-quadrats by photocopying graph paper onto acetates. Lay an acetate grid over the pollution sample (sticky tape). Use random co-ordinates to locate a quadrat. Estimate and record the percentage frequency of black particulates in the chosen quadrat. Repeat this estimation of particulates between 15-20 times for different quadrats, and calculate an average percentage cover of particulates for the sample site.
The investigation has many interesting areas to consider and highlights the way scientists work in the ‘real world’. Pupils can use the prompt questions (see Evaluation worksheet) to consider how appropriate the methods were and the difficulties of controlling variables out in the field. Pupils can go on to consider primary data collected by the nearby pollution monitoring stations and observe how these data vary on a daily and seasonal basis.