GCSE

# Conclusions

## 1. Conclusions

### Describing bar charts

For each bar chart write a few sentences about which are the highest and the lowest bars. Include numbers from the bar chart to make the comparison clearer.

The bar chart below shows mean cross-sectional area at five sampling sites along a stream.

Site 1 has the lowest cross-sectional area (0.5 m2). Site 5 has the highest cross-sectional area (2.3m2). The cross-sectional area at Site 5 is approximately five times larger than the cross-sectional area at Site 1.

### Describing line graphs

For each line graph write a few sentences about the trend that you can see. Is it a smooth line or a zig-zag?

The line graph below shows mean wetted perimeter with distance downstream from the source.

Wetted perimeter increases with distance from the source. It is 0.8 m at 0.5 km from the source and 2.4 m at 3.0 km from the source. However wetted perimeter does not rise steadily. Wetted perimeter does not increase much between 1.3 km and 1.8 km of the source, but there is a rapid increase in wetted perimeter between 1.8 km and 2.3 km of the source.

### Describing scattergraphs

For each scattergraph write a few sentences about:

• the direction of the relationship (is it positive, is it negative, or is there no relationship?)
• the strength of the relationship (is is strong, or is it weak?)
• if there any anomalous results (points that lie a long way from the best-fit line)?

Go through each table, chart and graph in turn. Write a few sentences to explain what you have just described. Try to use geographical words as much as you can.

The best explanations will give reasons for the strength of relationships and for any anomalous results.

Example: The scattergraph is a plot of mean cross-sectional area against mean velocity. There is a positive relationship between the two variables. As cross-sectional area increases, velocity also increases. The best-fit line shows that it is a fairly strong relationship. The points are close to best-fit line.

Why? An increase in cross-sectional area means that the river is becoming wider and deeper. A smaller proportion of the water in the river is in contact with the bed and banks. This means that less energy is lost to friction, so the water has more kinetic energy and can move faster.

It is not a perfect relationship because different shaped channels have different wetted perimeters. A square-shaped channel loses less energy to friction than a wide and shallow channel.