One beautiful day (we were lucky with the weather) the boys and girls and their teachers went to the Harold Porter Botanical Gardens in Betty's Bay.
Each group was given a chart showing pictures of insects and each insect was given a value. The Group Leader took them to the stream to search for the insects shown on the charts. Then she showed them that by adding up the values of the various insects they saw, they could get to a total which was a pretty good indication of how healthy the water was.
After that they went to different pools and various parts of the stream in their groups to search for insects and tally up their totals.
It was great fun, especially as it was absolutely necessary to wade into the water, "want Juffrou, ek moes hom volg anders sou ek hom nie gevang nie".
When the children had satisfied themselves the water was pristine and they were all sitting in a circle again, their Group Leader asked them if they had ever seen these insects hovering over streams where oil had been tipped in or paint tins and other junk thrown. The children looked very thoughtful.