Olympiad Test: Winds, Storms And Cyclones - Class 7 MCQ

Warmer air rises higher. This is because gases expand when they are heated. 

Anemometer: Instrument for Measuring Wind Speed
An anemometer is an instrument used for measuring wind speed. It is commonly used in meteorology, aviation, and environmental monitoring. When comparing an anemometer to other objects or instruments, the most similar option is a speedometer. Here's a detailed explanation:
1. Anemometer
- An anemometer is a device that typically consists of cups or propellers mounted on a horizontal axis.
- These cups or propellers rotate when the wind blows, and the speed of rotation is directly proportional to the wind speed.
- The anemometer converts the rotational speed into an electrical signal, which can then be displayed or recorded for measurement and analysis.
2. Speedometer
- A speedometer is an instrument found in vehicles, such as cars, motorcycles, or bicycles, that measures the speed at which the vehicle is traveling.
- It uses a combination of mechanical and electrical components to display the speed of the vehicle in miles per hour (mph) or kilometers per hour (km/h).
- The speedometer calculates the speed based on the rotation of the vehicle's wheels or other relevant factors.
3. Similarities between Anemometer and Speedometer
- Both an anemometer and a speedometer measure the speed of an object or phenomenon.
- They both use rotational motion to determine the speed.
- The measurement is based on the rate of rotation of specific components.
- The output is usually presented in numerical form on a display.
4. Differences between Anemometer and Speedometer
- An anemometer measures wind speed, while a speedometer measures the speed of a vehicle.
- The units of measurement are different; anemometers typically measure wind speed in meters per second (m/s) or miles per hour (mph), while speedometers measure vehicle speed in mph or km/h.
- Anemometers are used in meteorology and environmental monitoring, while speedometers are primarily used in transportation.
Therefore, when comparing an anemometer to other options given in the question, the instrument that is most similar to an anemometer is a speedometer (Option D).

The given question is asking about the movements usually shown by cold winds and warm winds. Let's analyze the options and determine the correct answer.
Option A: lateral, vertical
- Cold winds showing lateral movements means they move horizontally. This is often observed in the case of cold fronts.
- Warm winds showing vertical movements means they move vertically, generally in an upward direction. This is commonly seen in the case of convection currents.
Option B: vertical, lateral
- Cold winds showing vertical movements contradicts the general behavior of cold winds. Cold winds are typically associated with horizontal movements.
- Warm winds showing lateral movements contradicts the general behavior of warm winds. Warm winds are usually associated with vertical movements.
Option C: lateral, lateral
- Cold winds showing lateral movements is a valid possibility.
- Warm winds showing lateral movements contradicts the general behavior of warm winds. Warm winds are usually associated with vertical movements.
Option D: vertical, vertical
- Cold winds showing vertical movements contradicts the general behavior of cold winds. Cold winds are typically associated with horizontal movements.
- Warm winds showing vertical movements is a valid possibility.
Based on the analysis of the options, we can conclude that option A, lateral, vertical, is the correct answer.

When a wind flows very fast, a low pressure is produced temporarily which is filled by the rushing wind nearby. 

Incorrect Statement: B: slow moving air is called wind.
Explanation:
The statement is incorrect because "slow moving air" is not referred to as wind. Wind is defined as the movement of air from an area of high pressure to an area of low pressure. It is characterized by the horizontal flow of air across the Earth's surface.
Correct Statements:
A: rain, thunder and lightning are natural phenomena.
C: high-speed winds are accompanied by reduced air pressure.
D: earthquake, landslide and tsunami happen due to geological changes.
- Rain, thunder, and lightning are natural phenomena that occur in the atmosphere.
- Wind is the movement of air caused by differences in air pressure.
- High-speed winds are often associated with reduced air pressure.
- Earthquakes, landslides, and tsunamis are geological events caused by tectonic activity and changes in the Earth's crust.
Note: It is important to read the question carefully and evaluate each statement to determine which one is incorrect.

Upon heating, the molecules in the gases go further away from each other and thus become lighter. 

The winds coming from the southwest blow over the Indian ocean and bring lots of rains. 

The energy contained in the gaseous form (vapour) is more than the energy contained in the liquid form (water), therefore when vapour changes to water it loses some heat.

Best thing to do during heavy lightning:
- Stay indoors: It is best to stay indoors during heavy lightning as this provides the most protection from lightning strikes.
- Avoid metallic doors and windows: Stay away from doors and windows with metal frames as they can conduct electricity if struck by lightning.
- Avoid using electronic devices: Lightning can cause power surges, so it is best to avoid using electrical appliances and devices during a storm.
- Avoid water bodies: Contrary to option A, going into water bodies during heavy lightning is dangerous as water is a good conductor of electricity. It is important to stay away from water bodies during a storm.
- Avoid tall trees and open spaces: Standing under a tall tree or lying on the ground in an open place increases the risk of being struck by lightning. It is important to seek shelter in a safe, enclosed area.
- Wait for the storm to pass: Lightning can continue even after the rain has stopped, so it is important to wait for the storm to completely pass before venturing outside.
Remember, the best course of action during heavy lightning is to stay indoors, away from metallic doors or windows, and avoid using electronic devices until the storm has passed.

Salinity is harmful to the plants. During cyclones, the sea waves rise high and flood the land making the soil saline (infertile). 

Even when the cyclone is very far, strong winds push water towards the shore causing huge water waves. 

The winds on the earth do not flow in the exact "north to south" or "south to north" directions because of the rotation of the earth.
Explanation:
The rotation of the earth on its axis causes the winds to flow in a more complex pattern. This is known as the Coriolis effect. The Coriolis effect is a result of the rotation of the earth and the fact that different parts of the earth have different linear velocities due to their distance from the axis of rotation.
Here is a detailed explanation of why the winds do not flow in the exact "north to south" or "south to north" directions:
1. Coriolis Effect:
- The rotation of the earth causes a deflection in the path of moving objects, including air masses.
- As the earth rotates, different parts of the earth's surface move at different speeds due to their distance from the axis of rotation.
- This variation in speed creates a deflection in the path of the moving air masses, causing them to curve.
- In the Northern Hemisphere, the deflection is to the right, while in the Southern Hemisphere, it is to the left.
2. Three-Cell Model of Atmospheric Circulation:
- The winds on the earth are influenced by the three-cell model of atmospheric circulation: the Hadley cell, Ferrel cell, and Polar cell.
- The Hadley cell is located near the equator and is characterized by warm air rising at the equator, moving towards the poles, and sinking at around 30 degrees latitude.
- The Ferrel cell is located between the Hadley cell and the Polar cell and is characterized by air rising at around 60 degrees latitude, moving towards the poles, and sinking at around 30 degrees latitude.
- The Polar cell is located near the poles and is characterized by cold air sinking at the poles, moving towards lower latitudes, and rising at around 60 degrees latitude.
3. Jet Streams:
- The rotation of the earth and the temperature differences between air masses create high-speed wind currents called jet streams.
- Jet streams are strong, narrow bands of winds that blow from west to east in the upper levels of the atmosphere.
- The jet streams influence the movement and direction of surface winds, causing them to flow in a more complex pattern.
In conclusion, the winds on the earth do not flow in the exact "north to south" or "south to north" directions because of the rotation of the earth, which causes the Coriolis effect and influences the three-cell model of atmospheric circulation and the formation of jet streams.

Sea and land breezes are caused because of an uneven heating of the earth and through convection currents. 

A ball falls down to the ground because of gravity. 

Because of the curved upper surface of the aeroplane more air flows in the same time as compared to the lower surface. Therefore, the pressure over the aeroplane  is less when compared to the lower surface. 

Condition necessary for the development of cyclonic storm:
There are several conditions that are necessary for the development of a cyclonic storm. These include:
1. Atmospheric instability:
- Cyclonic storms are formed due to the combination of warm and cold air masses.
- The presence of atmospheric instability, such as a significant difference in temperature and pressure between these air masses, provides the necessary conditions for the development of a cyclonic storm.
- This instability creates a favorable environment for the formation of cyclones.
2. High relative humidity:
- High levels of moisture in the atmosphere are essential for the development and intensification of a cyclonic storm.
- The presence of high relative humidity promotes the condensation of water vapor, leading to the formation of clouds and precipitation.
- This moisture supply is crucial for the sustenance and strengthening of the cyclonic system.
3. Warm sea temperature:
- Cyclonic storms derive their energy from warm ocean waters.
- The presence of a warm sea surface temperature of at least 26.5°C (79.7°F) is necessary for the development and intensification of a cyclonic storm.
- The warm sea surface temperature provides the necessary heat and moisture for the storm system to grow and strengthen.
4. All of the above:
- All the aforementioned conditions are necessary for the development of a cyclonic storm.
- Atmospheric instability, high relative humidity, and warm sea temperature act together to create a conducive environment for the formation and intensification of cyclones.
In conclusion, the development of a cyclonic storm requires atmospheric instability, high relative humidity, and warm sea temperature. These conditions provide the necessary ingredients for the formation, sustenance, and strengthening of cyclones.

Introduction:
Cyclones are powerful and destructive weather phenomena characterized by strong winds and heavy rainfall. Certain regions of the world are more prone to cyclones due to their geographical location and climate patterns.
Identification of the most likely affected country:
Among the given options, Indonesia is the most likely country to be affected by cyclones.
Reasons:
1. Geographical location: Indonesia is an archipelago located in Southeast Asia, situated along the equator. Its position between the Indian Ocean and the Pacific Ocean makes it susceptible to cyclones.
2. Tropical climate: Indonesia experiences a tropical climate, which provides ideal conditions for cyclone formation. Warm ocean waters, high humidity, and low wind shear contribute to the development of cyclones.
3. Ring of Fire: Indonesia lies within the Pacific Ring of Fire, an area notorious for seismic activity. Volcanic eruptions and earthquakes can trigger underwater landslides and tsunamis, which can augment the impact of cyclones.
4. Historical records: Indonesia has a history of being hit by cyclones. For example, the country experienced devastating cyclones such as Cyclone Cempaka in 2017 and Cyclone Nargis in 2008.
Conclusion:
Considering the geographical location, tropical climate, the presence of the Ring of Fire, and historical data, Indonesia is the country most likely to be affected by cyclones among the given options.

When we suck into the straw, a low pressure is created in it, which makes the higher pressure in the bottle to push the drink into the straw. 

When winds blow over a weak roof, it creates a low pressure over it and a high pressure inside causing the roof to be blown off.
Opening the doors and windows reduces this pressure difference and avoids the roof from being blown off.