Sir William Mvula - Agriculture

24/11/2025

Geography
Water fall
Dziwe lakhalamba waterfalll Mulanje

Waterfalls primarily form through differential erosion, where a hard, resistant layer of rock sits on top of a softer, more easily eroded layer. As a river flows over this area, the water erodes the soft rock much faster than the hard rock, creating a steep drop. This process is aided by gravity, which increases water speed, and erosion at the base forms a plunge pool and can eventually cause the hard rock overhang to collapse, causing the waterfall to retreat upstream and carve out a gorge.

04/05/2025

Chichiri Secondary School
Geography
Form 3 class
@ Zomba plateau
Exploring

12/03/2025

*Geography Lesson*
*Topic: Air Pressure*
*Sub-Topic: Type of Barometers*

*Types of Barometers*
a. Mercury
b. Aneroid

*a. MERCURY BAROMETER*
It is made up of a glass tube, mercury and a container. It is made by taking a glass tube filled with
mercury. While sealed at the mouth, the glass tube is turned upside down in a container filled with mercury.

*HOW DOES A MERCURY BAROMETER WORK?*
It works by balancing the weight of a column of mercury against the weight of the column of air.
When the atmospheric pressure increases, it presses on the surface of mercury in the container.
This forces mercury to rise in the glass tube occupying the vacuum and recording the high
pressure.
When the atmospheric pressure decreases, there is little force exerted on mercury in the
container which makes mercury in the glass tube to drop thereby recording low pressure.

11/03/2025

*Geography Lesson*

*Topic: Air pressure*

*Definition of Air pressure*
This is the amount of force exerted by the atmospheric air on the earth’s surface.

*MEASUREMENT OF AIR PRESSURE*
✅Air pressure is measured by using an instrument called a *BAROMETER* . It is measured into units
called *MILLIBARS* (mb).

✅The pressure of air at sea level is 1013.25 mb which is equivalent to the weight of a column of
mercury 76.0 cm (760mm) high.

*TYPES OF BAROMETERS*

a. Mercury barometer
b. Aneroid barometer

26/11/2024

21/04/2024

Geography
Form 2 essay

Explain four negative effects of population increase on Malawian natural resources

*Deforestation:** Population increase often leads to higher demand for agricultural land and fuelwood, resulting in extensive deforestation. This can disrupt ecosystems, reduce biodiversity, and lead to soil erosion and loss of wildlife habitats.

**Water Scarcity:** A growing population puts pressure on water resources for drinking, agriculture, and industry. In Malawi, this can exacerbate water scarcity issues, leading to competition between sectors and compromising the availability of clean water for both humans and ecosystems.

*Soil Degradation:** Intensive agriculture to support a larger population can lead to soil degradation through overuse of fertilizers, pesticides, and unsustainable farming practices. This can decrease soil fertility, reduce crop yields over time, and contribute to land degradation.

**Waste Pollution:** Increased population often corresponds with higher waste generation, including plastic pollution, organic waste, and industrial pollutants. Improper waste management can contaminate soil, water bodies, and air, posing health risks to humans and wildlife and degrading the quality of natural resources.