iGeo 2012, Писмен тест — Задача 27. Section E: Rivers
Written Response Test — Question and Answer Booklet — 9th International Geography Olympiad — Cologne, Germany — 21–27 August 2012 · 21 август 2012 г. · 2 т.
Внимание: Бележка към темата
The Source Booklet (Sources A1–F1) referred to in the questions is not part of this paper's files; only the copies of Source B1 Maps A and B and Sources E1 and E3 printed in the answer booklet are reproduced.
Instructions for the students
- This test consists of 6 sections.
- The maximum total mark is 90. The mark for each question is given at the beginning of the question.
There are a maximum of 15 marks for each section. - Give only the required number of answers (reasons, examples, et cetera). For instance, if the question asks for 2 reasons and you give more than 2, only the first 2 reasons will be marked.
- Answer all questions in the spaces provided in this booklet.
- Check the backs of pages as questions are printed on both sides of a page.
- Fill in your name, team and student number on the front page of this booklet.
- Fill in your iGeo student number in the boxes on top of the pages in this booklet.
- The Source Booklet contains the maps and figures referred to in the questions.
- Time: 180 minutes for non-native English speakers; 150 minutes for native English speakers.
- Non-native English speakers may use bilingual dictionaries during the test.
- You may use a calculator during the test.
- You may use the atlas provided during the test.
Good luck!
Marking scheme - overview
| section A | section B | section C | section D | section E | section F |
|---|---|---|---|---|---|
| 1 - 2m | 1 - 1m | 1 - 3m | 1 - 3m | 1 - 4m | 1 - 4m |
| 2 - 1m | 2 - 1m | 2 - 3m | 2 - 8m | 2 - 1m | 2 - 2m |
| 3 - 4m | 3 - 1m | 3 - 3m | 3 - 4m | 3 - 3m | 3 - 3m |
| 4 - 1m | 4 - 9m | 4 - 2m | 4 - 1m | 4 - 6m | |
| 5 - 1m | 5 - 3m | 5 - 4m | 5 - 1m | ||
| 6 - 2m | 6 - 3m | ||||
| 7 - 4m | 7 - 2 m | ||||
| 15 marks | 15 marks | 15 marks | 15 marks | 15 marks | 15 marks |
Условие
Study Source E4 in the Source Booklet.
Explain how potholes are formed.
Решение
2 marks
Explanation key here.
- Potholes are circular shaped; cylindrical; vary in depth; some merge with each other; some are exposed above the river level. The water can be seen to be swirling/eddying. This creates a shallow hollow that is deepened by the same process 1
- The water contains some of the load being carried by the river and this hits the base and sides of the hole to both widen and especially deepen it, smoothing the edges. This is an example of the abrasion process 1
- It is most effective at times of high velocity and discharge. As vertical erosion is the dominant process, potholes tend to form well above base level where potential energy is relatively high 1
Оригинал в Архива: 2012WRTQandA.pdf · официални решения: 2012WRTmarkingscheme.pdf