Question 1 Report
The table below shows sediment collected from three points across a beach near a river mouth after a winter storm. Fig. 1 shows the sampling transect from the cliff to the low-tide mark. The pupils used callipers to measure the longest axis of 50 pebbles at each point. Sediment size can show how wave energy varies across a beach.
| Point on transect | Mean pebble length (mm) | Mean mass (g) |
|---|---|---|
| Backshore | 54 | 126 |
| Mid-beach | 31 | 42 |
| Near low-tide mark | 12 | 5 |
(a) Which point has the smallest mean sediment size? [1]
(b) Draw a bar chart to show mean pebble length at the three points. [2]
(c) Outline one reason why the largest pebbles are found on the backshore. [2]
(a) Near low-tide mark [1] (b) Award [1] for correctly scaled axes with units and three categories; [1] for bars at 54 mm, 31 mm and 12 mm (c) Strong swash can carry and deposit larger pebbles high on the beach [1]; finer material is more easily moved back downslope by backwash [1]
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