Which Site Gets the Bus? A Two-Day Survey of the Kuzuryu River
A third-year class of 32 students at a junior high school in Echizen City has two weekdays in late October for a field survey. The theme is "how the Kuzuryu River links the mountains to the Sea of Japan." The class can use the hired bus on one day only, at a cost of 32,000 yen; the total budget is 40,000 yen, and everyone must be back at school by 16:00. Three sites are proposed. Site A is the Kuzuryu Dam area, 1 hour 40 minutes away by bus, where a dam official can talk for 60 minutes. Site B is a rice-terrace village in the middle reaches, 30 minutes away by school bus but also served by a community bus with five round trips a day. Site C is the river mouth and fishing port at Mikuni, 40 minutes by bus, where the fishery cooperative can meet the group for 90 minutes. Last year's report described the river as if it existed only near the sea, and the teacher wants that corrected. School rules require one first-aid-trained teacher for every 16 students; two teachers are available.
1. The class can hire the bus only once. Which site should get the bus day, and how should the class spend the other day? Use the theme, the timetable and the budget in your answer.
Read the worked answer
Site A should get the bus day, and Site B should be visited on the other day.
- Theme: last year's weakness was that the river was described only near the sea, so the class needs upstream and middle-reach evidence. The river-mouth site C repeats what was already done.
- Access: Site A is 1 hour 40 minutes by bus each way and has no community bus, so it can only be reached on the bus day. Site B has five community-bus round trips a day, so it can be done without the hired bus.
- Timetable: leave 8:30, arrive about 10:10, hear the 60-minute talk from 10:30 to 11:30, eat lunch, leave at 12:30 and be back around 14:10 - comfortably before 16:00.
- Budget: 32,000 yen for the bus leaves 8,000 yen, which covers 32 students' community-bus fares.
- Safety rule: two teachers for 32 students is exactly 1 per 16, so the class must not split into three separate groups.
2. One student says, "At Site B we should interview as many residents as possible, because more interviews make the results more accurate." Evaluate this plan.
Read the worked answer
More interviews is not the same as better evidence.
Accuracy depends on whether the people interviewed represent the groups involved, not only on how many there are. In a small, ageing rice-terrace village, 40 people stopped in the street will be mostly elderly residents; farmers who work elsewhere, shop owners, the community-bus driver and young families would be left out, so the picture would be systematically biased. Interviewing everyone also uses up the limited survey time.
A better plan: choose a few interviewees deliberately for different roles, ask the same fixed questions to each so answers can be compared, and record each person's age and occupation so readers can judge the sample. For the village as a whole, use town statistics (population by age, number of farm households) rather than trying to count people on the day. Finally, keep facts ("the bus runs five times a day") separate from opinions ("the bus is inconvenient").
3. The report must plot the survey points on a map. Which map should the class use, and what should be shown on it?
Read the worked answer
A 1:25,000 topographic map of the Kuzuryu basin, not a small-scale map of Japan.
At 1:1,000,000 a single village or the dam site would be a dot, so the reader could not see the relationship between the sampling points and the river. At 1:25,000 the class can mark the exact survey points, the river channel, the elevation and the basin boundary.
On the map they should add: sampling points numbered to match the report; arrows showing the direction of flow from the dam through the middle reaches to the river mouth, so the mountain–middle–sea link is visible at a glance; a legend; a scale bar; and the same scale on every panel if they show several maps, so the panels can be compared honestly. A title stating the date of the survey is also needed, because river conditions differ by season.