Science 2 Marks Questions

At night, the water cools down more slowly than the land. So, at mid-night, cool wind from the land moves towards the sea. Therefore, at midnight the flag mounted on a flag post near the sea’ coast flutters in the direction of sea.

1. Strong water waves are produced by winds.
2. Strong winds push water towards the shore.
3. Low pressure in the eye lifts water surface in the centre and sea water enters coastal areas.

The main effects of tropical cyclones include heavy rain, strong wind, large storm surges at landfall, and tornadoes. The destruction from a tropical cyclone depends mainly on its intensity, its size, and its location.

Wind is air in motion. It is produced by the uneven heating of the earth's surface by the sun. Since the earth's surface is made of various land and water formations, it absorbs the sun's radiation unevenly. Two factors are necessary to specify wind speed and direction.

The monsoon winds carry water and it rains. Clouds bring rain and give us happiness. Farmers in our country depend mainly on rains for their harvests. So, monsoon winds are helpful.

Some precautions are:

1. Put heavy stones on it.
2. Screw it tight.

Due to uneven heating of land and ocean water,

1. In winter season The uneven heating of land and water generates winds from the North-West colder land which carry little water. It brings small amount of rain in winter season.
2. In summer season The uneven heating of land and ocean water generates wind from the South-West direction. These winds carry lot of water from the Indian ocean.

We can find the wind direction using a Wind Vane or Weather Vane or Weather Cock. It consists of a flat metallic sheet generally cut into shape of a cock or arrow which is mounted on disk and free to move around a axial shaft and point in the direction of wind. They are typically used as an architectural ornament to the highest point of a building. Also we can find the direction of light wind using smoke from incense sticks. The direction of smoke will indicate the wind direction.

During summer, when the land gets warmed and temperature of land becomes higher than that of water in ocean. The air above the land gets heated and rises. Therefore, the cold wind flows from the ocean towards the land. These are monsoon winds which bring water and cause rain.

1. Heavy rainfall
2. Deforestation

Tornadoes can appear as a traditional funnel shape, or in a slender rope like form. Some have a churning, smoky look to them, and other contains "multiple vortices", which are small, individual tornadoes rotating around a common center. Even others may be nearly invisible, with only swirling dust or debris at ground levels as the only indication of the tornado's presence.

Wind is the fastest growing source of electricity in the world. It's often one of the least expensive forms of renewable power available. Some experts say it can sometimes be the cheapest form of any kind of power. Generating power from the wind leaves no dangerous waste products behind. Best of all, its supply is unlimited.

Windmills work because they slow down the speed of the wind. The wind flows over the air foil shaped blades causing lift, like the effect on airplane wings, causing them to turn. The blades are connected to a drive shaft that turns an electric generator to produce electricity.

The basic ingredients used to make a thunderstorm are moisture, unstable air and lift. You need moisture to form clouds and rain. You need unstable air that is relatively warm and can rise rapidly. Finally, you need lift. This can form from fronts, sea breezes or mountains.

Pressure difference is created in the nature by the heat of the sun. When it falls on the earth surface, the surface of the earth gets heated and air above it also gets warm and becomes light weight and moves upward. Thus, the pressure difference is created.

The following three precautions must be taken to protect oneself from the lightning of thunderstorm.

1. Do not take shelter under an isolated tree.
2. Do not lie on the ground
3. Do not take shelter under an umbrella with a metallic end.

On cooling the air, contraction of air takes place. So, the air inside the bottle contracts due to the low temperature. Hence, the bottle collapses due to the outside pressure.

1. Do not lie on the ground or take shelter under an isolated tree.
2. If you are in water, move out of it.
3. Do not take shelter under an umbrella with a metallic rod.

In the afternoon, the land gets heated faster than the water. The air over the land becomes hotter and rises up, creating a drop in pressure. This causes the winds to flow from the sea towards the land. Thus, the clothes will be blown towards the house because of sea breeze flowing towards the land.