A group of geography students investigated downstream changes in river velocity. To do this, they used a tennis ball as a float to measure the time taken for it to travel a 5-metre distance at a single point in the channel cross-section at three different locations along the river course on a single Tuesday afternoon.
Suggest two ways that this data collection method could be adapted to make the data more reliable.
102 exam-style questions on AQA GCSE Geography Fieldwork. Each one has a worked solution and a mark scheme showing where the marks go.