A. Choose the correct option.
- Wind is caused because of
a. the movement of the Earth around the Sun
b. uneven heating of the Earth
c. the position of the moon
d. trees moving
Answer: b. uneven heating of the Earth - Moving air is responsible for
a. creating a low-pressure area
b. uneven heating of the Earth
c. making an anemometer move
d. both (a) and (c)
Answer: d. both (a) and (c) - A wind vane is used to find
a. the North-South direction
b. wind speed
c. the East-West direction
d. wind direction
Answer: d. wind direction - An anemometer is used to find
a. the North-South direction
b. wind speed
c. the East-West direction
d. wind direction
Answer: b. wind speed - Which of the following should we not do during a cyclonic storm?
a. Take shelter under a tree
b. Go to the beach to check out the weather
c. Go out into the sea for fishing
d. all of the above
Answer: d. all of the above
B. Fill in the blanks with the correct words.
- A strip of paper will be lifted (blown down/lifted) if we blow air in a horizontal direction over it.
- Roofs can be blown off because moving air creates a low (low/high) pressure.
- A wind vane points in the direction (direction/perpendicular direction) of the wind.
- Cyclones form in the oceans near the equator (equator/poles).
- Cyclones become stronger if they pass over warm (warm/cold) water of the ocean.
C. Match the Following.
| Item | |
| 1. Wind | a. atmospheric disturbances with very high speed winds |
| 2. Storm | b. storms occurring over oceans near the equator |
| 3. Wind Vane | c. wind speed |
| 4. Anemometer | d. moving air in the atmosphere |
| 5. Cyclone | e. wind direction |
| Item | Answer |
| 1. Wind | d. moving air in the atmosphere |
| 2. Storm | a. atmospheric disturbances with very high speed winds |
| 3. Wind Vane | e. wind direction |
| 4. Anemometer | c. wind speed |
| 5. Cyclone | b. storms occurring over oceans near the equator |
D. Give reason for the following.
- A heated metal can crumples up when held under cold running water.
Answer: Metal expands when heated and contracts when cooled. The rapid cooling by cold water causes the metal to contract suddenly and unevenly, leading to a crumpling effect. - Roofs can be blown off during a strong wind.
Answer: When strong wind blows over a roof, it creates a region of low pressure above it, according to Bernoulli’s principle. The higher air pressure inside the house then pushes upwards on the roof from below. If this upward force is strong enough, it can blow the roof off. - The strip of paper is lifted when we blow over it.
Answer: Blowing air over the paper strip moves the air rapidly, creating a zone of low pressure above it. The stationary air below the strip has higher pressure, and this difference pushes the paper upwards, lifting it.
- Storms can be destructive.
Answer: Storms are destructive because they involve extremely high-speed winds, heavy rainfall, and sometimes lightning or hail. These can uproot trees, damage buildings, flood areas, and cause widespread harm to life and property.
E. Answer the following questions.
- What causes storms?
Answer: Storms are caused by atmospheric disturbances, primarily due to the uneven heating of the Earth’s surface by the sun. This creates differences in air temperature and pressure, leading to the rapid movement of air (wind). When this movement becomes intense and is accompanied by conditions like moisture and low pressure, it develops into a storm. - What are the effects of a severe storm?
a. On the land – Uprooting of trees, damage to buildings, power outages, flooding, destruction of crops, and loss of life.
b. At sea – Formation of massive, dangerous waves that can capsize ships, coastal erosion, and storm surges that inundate coastal areas. - Explain the construction and working (with rough diagrams) of
a. Wind vane –
A wind vane consists of an arrow (or a shape with a large tail) mounted on a free-spinning rod. The arrow is balanced so it can rotate freely. It is often marked with the cardinal directions: North, South, East, and West.
Working: The wind blows against the large tail of the vane, causing the arrow to rotate. The arrowhead points into the wind. Therefore, if the arrowhead points to the East, it indicates that the wind is blowing from the East.
c.Anemometer –
Working: The wind pushes into the concave sides of the cups, causing the arms to rotate. The stronger the wind, the faster the rotation. The speed of rotation is measured and converted into wind speed, typically in kilometers per hour (km/h) or meters per second (m/s).
- What are the dangers of a storm to people and property?
Answer: Storms pose multiple dangers, including injury or loss of life from collapsing structures, flying debris, and electrocution from downed power lines. They can cause extensive property damage to homes, vehicles, and infrastructure. Flooding can contaminate water supplies, and disruptions can lead to a lack of essential services like electricity and water. - What are the safety measures that we should take when there is a storm warning?
Answer:- Stay indoors and away from windows, skylights, and glass doors.
- Secure or bring inside any loose outdoor objects.
- Avoid contact with electrical equipment and plumbing.
- Do not walk or drive through flooded areas.
- If in a vehicle, try to safely park away from trees and power lines.
- Have an emergency kit ready with a flashlight, batteries, first-aid, and water.
- Follow official instructions, which may include evacuating the area.