Let's Find Out About the Weather !!!

Different types of clouds are formed at different heights in the atmosphere.

The 3 main clouds are : 

• Cumulus clouds
• Stratus clouds
• Cirrus clouds

Cumulonimbus

This clouds is a cumulonimbus clouds. Cumulonimbus clouds extend from a height 2000 m to 16 000 m in the atmosphere. When cumulus clouds turn into dark grey , they are called cumulonimbus which can produce rain, hail or lightning.

Cirrus
Cirrus clouds are formed very high in the atmosphere at 8000 m. These clouds are wispy and light, and look like feathers in the sky.

 Nimbostratus
Nimbostratus clouds are formed below a height of 2400 m in the atmosphere. They bring long steady rain and a resemble grey blankets strecthed out in the sky.

 Cumulus 

Cumulus clouds are formed at about a height of 2000 m in the atmosphere. Cumulus clouds are white and fluffy like cotton balls.

Stratus 

Stratus clouds are formed below a height 2000 m in the atmosphere. Stratus clouds are flattened sheets of clouds that may stay over certain location for some time. They cause overcast weather.

Fog

A fog is just like a low-lying cloud. It hovers just above the ground because it is formed when the ground is cold, such as winter or at night. The water vapour in the air condenses into tiny droplets of water to form fog.

Dew

Dew appears as drops of water on cold objects usually in the early morning or late evening. Dew is formed when water vapour in the air comes in contact with a cold object of a temperature at or below the dew point. The temperature at which droplets can form is called the dew point.

The water vapour then condenses to form small droplets on the cold surface.

Hail

Hail is a form of precipitation that falls from sky as clumps of ice. Precipitation is produced when water vapour from the sky condenses and falls to the ground.

 Formation of hail 

1. During thunderstorms, there are updrafts or upward currents of air, caused by the rising warm air.
2. The updrafts may be strong enough to carry raindrops into the upper levels of the atmosphere.
3. The upper levels are extremely cold so the raindrops freeze as ice crystals.
4. As the ice crystals become larger and heavier, they can no longer be supported by updrafts.
5. They then fall to the ground as hail stones.

Wind

The movement of air causes wind.

Formation of wind

1. When the surface of earth is heated up by the Sun, the air above it is also heated up.
2. The warm air expands and rises into the upper atmosphere. This creates a region of low pressure, where there is less air. 
3. In another region, where the surface of Earth is cooler air above it is also cooler.
4. Thus, cooler air from this region of higher pressure rushes in to replace the warm air.

Effects of wind on living things and the environment

Wind affects the activities of man, animals, plants and the environment. Man, other animals and plants may use wind for their benefit but sometimes, wind may have a negative effect on the environment.

Man

Man relies on wind for some recreational activities such as windsurfing and kite-flying. We rely on wind to generate electricity in wind power stations. However, strong winds may damage properties and affect aviation.

Animals

Some animals make use  of the wind to smell their prey. The smell of their predators in the wind also helps warn some animals of any dangers.

Plants

Some plants need the wind to disperse their seeds. However, strong winds may uproot trees.

Environment

Wind causes rocks to erode. Strong winds that carry heavy rain, such as tornadoes and hurricanes, can cause floods.

Sea breeze and land breeze

Wind is also formed when land and water are heated.

Heating of land and water causes the formation of sea breeze during the day and land breeze during day and night.

Heating of land and water

Some surfaces take a longer time to heat up and to lose heat than others. Water takes longer time to absorb heat up to compared to land. It also takes a longer time to lose the heat and the cool down compared to land.

Formation of sea breeze

During the day, the Sun heats up the sea and land. The movement of air from the sea to the land causes sea breeze during the day time.

1. The land absorbs the heat from the Sun and warms up faster than the seas.
2. The air aboves the land is heated up and rises.
3. Cooler air above the sea moves in to replace the warm air above the land.

Formation of land breeze

At night, there is no heat from the Sun. Both the sea and the land begin to lose heat. The movement of air from the land to the sea causes land breeze at night.

1. The land loses the heat faster than the sea, and cools down faster.
2. The air above the sea is now warmer and rises.
3.   Cooler air above the land moves in to replace the warm air above the sea.