Assessing pollution levels
Use the Assessing pollution worksheet.
Pollution is the addition to the environment of something which causes harm. We can measure the amount of pollution in water by calculating a Biotic Index, which works by giving each type of animal a score. Animals which are sensitive to pollution have a high score, while animals that are tolerant of pollution have a low score.
The Evaluation worksheet helps pupils to organise their evaluation of the method, and to make suggestions for possible improvements to improve the quality of the data collected.