Students in Brazil did fieldwork to investigate infiltration. Infiltration is the process by which water soaks into the soil. The students worked in two groups to do their fieldwork in a river valley. They created two transects (A and B) going away from the river. These are shown in Fig. 8 (Insert). The hypotheses investigated by the students were: Hypothesis 1: The infiltration rate decreases as distance from the river increases. Hypothesis 2: The infiltration rate decreases as soil moisture content increases. Soil moisture content is the quantity of water in the soil.

1. (a)Which one of the following pieces of equipment would they use to create a transect? Tick (✔) your answer. Equipment Tick (✔) callipers clipboard quadrat rope ruler[1]
2. (b)(i)To investigate Hypothesis 1 the students in group A collected data to measure the rate (speed) of infiltration at equal distances along transect A. Fig. 9 (Insert) shows the method they used to do this. Describe how the students measured the rate (speed) of infiltration to get the results shown in Table 1 (Insert).[3]
3. (b)(ii)The students recorded the water level in the tube every minute for 10 minutes or until there was no water left. The results of their measurements at sites 4 and 7 are shown in Table 1 (Insert). Use these results to complete the measurements for site 4 in Fig. 10 below. [Figure 10][2]
4. (b)(iii)The students then calculated the infiltration rate at each site. Their calculation for site 4 is shown below. Infiltration rate = fall in water level (mm) / time (min) = 70 / 10 = 7.0 mm per min Use the data in Table 1 to show the calculation which produced the result for site 7 in the space below.[1]
5. (b)(iv)The measurements of distance from the river and infiltration rate at the different fieldwork sites on transect A are shown in Table 2 (Insert). The students plotted these results on a graph, Fig. 11 below. Complete the graph by plotting the result for site 7. [Figure 11][1]
6. (b)(v)What conclusion would the students in group A make about Hypothesis 1: The infiltration rate decreases as distance from the river increases? Support your answer with evidence from Fig. 11 and Table 2.[3]
7. (c)(i)The students in group B did the same fieldwork along transect B shown in Fig. 8 (Insert). Their results are shown in Fig. 12 below. [Figure 12] Compare the results of the two groups on transects A and B. Use evidence from Figs. 11 and 12 in your answer.[2]
8. (c)(ii)As the results of the two groups were different their teacher checked their measurements and calculations and agreed that they had not made any errors. Suggest why the two groups got different results. Look at Fig. 8 to help you to answer.[4]
9. (d)(i)To investigate Hypothesis 2: The infiltration rate decreases as soil moisture content increases, the two groups of students measured the soil moisture content at each sampling site along their transects. Fig. 13 (Insert) shows students' fieldwork notes which describe the two different methods that the groups used. Suggest three advantages of method 2 for measuring soil moisture content. 1 2 3[3]
10. (d)(ii)The results for transects A and B are shown in Table 3 (Insert). Use this data to plot the results at site 3 on transect B in Fig. 14 below. [Figure 14][2]
11. (d)(iii)Which group's results agree with Hypothesis 2: The infiltration rate decreases as soil moisture content increases? Circle your decision below. Group A on Transect A Group B on Transect B Support your decision with evidence from Fig. 14 and Table 3.[3]
12. (e)If the students repeated their infiltration measurements after a week of heavy rain, how and why would the infiltration rates be different?[2]
13. (f)The area around the river where the students did their fieldwork is a popular tourist area. Suggest how and explain why people walking in the area might affect the infiltration rate.[3]

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