Sec 3 WB 7.2 Answer

Question (1)(a)
X: Headland
Y: Bay

Question (1)(b)
Headlands and bays are formed by wave erosion where the coast is made of alternating bands of resistant rocks and less resistant rocks. The different rates of erosion on the rocks by the waves cause the coast to be eroded unevenly. The areas made up of less resistant rocks are eroded by the waves to form bays while the areas with more resistant rocks will protrude into the sea to form headlands.

Sec 3 WB 7.1 Answer

Question (1)(a)
Strength of wind and fetch affect the size of waves.
The stronger the wind, the larger the size of the waves.
The longer the distance over which wind blows across open water, the larger the size of the waves.

Question (1)(b)
As the waves approach the shore, they will experience friction with the increasingly shallow sea bed. The waves lose energy and slow down.
However, the waves behind cause the waves infront to steepen.
When the waves become too steep, they will collapse and break to form a swash.
Gravity pulls the waves back into the sea, forming a backwash on the beach.

Question (2)
When waves reach the shore at an angle, the swash carries the sediments up onto the coast at the same angle. The backwash then carries the sediments back to the sea at a right angle to the coast due to the pull of gravity. This motion is repeated and gives rise to a zig-zag movement of sediments along the coast, known as the longshore drift.

Question (3)
The waves are acting mainly as an agent of deposition because the photograph shows small waves breaking on a genly sloping beach.

Sec 3 WB 6.4 Answer

Question (a)
High rainfall due to the rainy season led to flooding of River Pandan.
Large-scale deforestation by farmers upstream of River Pandan caused soil erosion, leading to flooding.

Question (b)
The flood has destroyed valuable farmland, including parts of the oil palm plantation in the grid squares 4833 and 4834. The flood has damaged property such as roads and buildings, for example, parts of the settlements near the river in grid square 4734.

Question (d) & Question (e)
* Any 2 measures with their respective advantages and disadvantages.

Re-sectioning of River Channel
Advantages:

• Increases the river's capacity to hold water, thus reducing floods


• Increases the amount and rate of flow of surface runoff from the surrounding areas into the river thus reducing floods


• Smoothening the channel bed and banks with cement and granite increases the speed of the river, thus reducing deposition and allowing the river to hold more water

Disadvantages:

• Leads to flooding downstream


• Destroys natural habitats and affects aquatic and marine life

Bank Protection e.g. building dykes
Advantages:

• Increases the river's capacity to hold water, thus reducing floods

Disadvantages:

• Leads to the accumulation of sediments on the river bed, causing the channel to become shallower and prone to flooding


• Over time, higher dykes, which are costly to build, have to be constructed to protect against future floods

Sec 3 WB 6.3 Answer

Question 1
In the upper course of the river where the gradient of the land is steep, the river flows quickly, resulting in vertical erosion. This causes the channel to deepen and to form a steep-sided V-shaped valley.
In the lower course of the river, the gradient of the land is gentler while the volume of water in the river is higher. This leads to an increase in the energy of the river, causing the river to erode horizontally rather than vertically. Lateral erosion in the lower course of the river causes the channel to widen and form a broad and flat-floored valley.

Question 2(a)
C: Owbow Lake
D: Meander

Question 2(b)
Constant erosion along the outer banks of the meander leads to the development of a loop. Over time, the loop becomes more pronounced and is separated by a narrow neck of land. Continual erosion and deposition cut off the loop from the main river, resulting in cut-off.
The sediments deposited eventually dam up the water in the cut-off and seal up the ends of the meander to form an oxbow lake.

Question 3(a)
Photo B shows a gorge.

Question 3(b)
When a river flows through an area with resistant rocks by its sides, it can only erode its channel vertically. Over time, a deep, narrow and steep-sided valley/ gorge is formed.

Question 4
Both are depositional landforms.
The rivers that form both landforms carry a heavy load of sediments.

Question 5
Erosion plays an important role in the formation of th waterfall shown in Fig.3, where the waterfall is formed through the erosion of rocks of different resistance.
Fig. 4 shows the formation of a waterfall as a result of faulting, or the displacement of rocks. When a river flows down from the edge of the uplifted block, a waterfall is formed.

World Vision Fund Raising...

Really hope this will come to pass...

Perhaps some of the Geography students can gather for a fund raising effort. I've looked at the school calendar and the only possible time is after the Year End Exams. Yup... still a long way to go. That'll give me plenty of time to plan the project. In any case, those who are interested to find out more or have decided to be involve, please leave your name and class in the comment box.

Project name: Child Health Now

Agency: World Vision Singapore

Target group: Children 5 and younger, and their mothers.

URL: http://worldvision.org.sg/childhealthnow.php

Method: Baking and selling cookies within school.

Students: Only Mdm Lee's Geography students - both past and present. Sorry, if I sound exclusive. This is very personal project which I want to share with my students.

Sec 1 WB 8.3 Answer

Question 2(a)
In the foreground, we can see a van covered with ash. The hot volcanic ash could damage vehicles.
The air is clouded with ash and smoke. This would make driving difficult for motorists.
The ash and smoke could remain in the air for a long time, causing people to fall sick.

Question 2(b)
Volcanic soils are fertile and suitable for growing crops.
A volcano is a tourist attraction and the locals can earn a living as tour guides.

Question 2(c)
Emergence transport would be made available to help people flee the area in case of a volcanic eruption.
A warning system could be set up and people can be warned and evacuated.

Sec 1 WB 8.2 Answer

Question 2(b)
The area along the "Pacific Ring of Fire" has the most number of active volcanoes.

Question 2(c)
The "Pacific Ring of Fire" lies on the plate boundaries where crustal movements are the most active.