Selina Concise Solutions for ICSE Class 7 Geography Chapter 5 Study of Weather

VALUES AND LIFE SKILLS

Question : Many people leave their pets in parked cars. They think they will be gone for a few minutes, or it will be alright to leave a window open. The temperature inside a parked car can rise up to more than 50°C in a matter of few minutes, irrespective of it being a hot or a cloudy day. What would be the right thing to do if you see a pet locked inside a car on a hot day ?
Answer:
Leaving pets locked in cars is never safe. But when the weather gets warmer, it can be deadly. High temperatures can cause irreparable organ damage and even death. Protecting animals from an unnecessary death is a problem we can all agree to prevent.
If you see a pet in danger, you should immediately try to locate the owner or notify the nearest security guard. Staying by the car and calling animal welfare services can help save the pet's life before the heat becomes fatal.
Teacher's Tip: Remember the phrase: "Hot cars kill - never leave a pet or a person inside, even for a minute!"
Exam Tip: In values-based questions, always mention the importance of empathy and taking quick, responsible action.

EXERCISES

A. Write true or false. Correct the false statements.

Question 1: A rise in temperature causes more condensation while a fall in temperature results in evaporation.
Answer: False.
Correct : Arise in temperature causes more evaporation while a fall in temperature results in condensation.
Heating water turns it into invisible gas through evaporation, while cooling gas turns it back into liquid through condensation. This cycle is the fundamental movement of water in our atmosphere.
Teacher's Tip: Think of "E" for Evaporation and "E" for Energy (heat) added.
Exam Tip: When correcting a statement, rewrite the whole sentence clearly to show you understand both processes.

Question 2: ‘4 o’clock showers’ are caused by cyclonic rainfall.
Answer: False.
Correct : ‘4 o’clock showers’ are caused by convection currents.
Daily heating in tropical areas causes air to rise rapidly, forming clouds that rain late in the afternoon. This predictable pattern is a classic example of convectional rainfall.
Teacher's Tip: Associate "4 o'clock" with the heat of the day peaking and then turning into rain.
Exam Tip: Always link daily afternoon rain specifically to the term "convection currents."

Question 3: Heavy rainfall occurs on the leeward or rain shadow side of a highland.
Answer: False.
Correct : Little rainfall occurs on the leeward or rain shadow side of a highland.
Clouds drop most of their moisture on the windward side as they climb the mountain. By the time the air reaches the other side, it is dry and sinking.
Teacher's Tip: Think of the windward side as the "wet" side and the leeward side as the "low-rain" side.
Exam Tip: Use the term "Rain Shadow" to describe the dry conditions on the leeward side for full marks.

Question 4: The direction of wind blowing on the surface of the earth is affected by the Coriolis force.
Answer: True.
The Earth's rotation creates a force that deflects moving air to the right in the North and to the left in the South. This invisible force is what determines the global paths of major winds.
Teacher's Tip: Imagine trying to draw a straight line on a spinning ball; the line will always curve!
Exam Tip: Mention the Earth's rotation if asked for the source of the Coriolis force.

Question 5: Cyclones and anticyclones are examples of variable winds.
Answer: True.
Unlike permanent winds that blow in one direction all year, variable winds change their path based on pressure systems. They are localized and temporary weather events that move across regions.
Teacher's Tip: "Variable" means "changeable," just like how a cyclone moves around on a map.
Exam Tip: Categorize winds correctly: permanent (Westerlies), periodic (Monsoon), and variable (Cyclones).

B. Fill in the blanks.

Question 1: The temperature of a place depends upon its latitude, altitude, distance from the sea, ocean currents, winds, cloud cover and slope and aspect.
Answer: latitude, altitude, distance from the sea, winds, cloud cover, slope, aspect.
These factors interact to create unique climates for every city on Earth. For example, being near the sea keeps a city cooler in summer and warmer in winter.
Teacher's Tip: Use the acronym "L.A.D.W.C.S.A" to remember all the factors affecting temperature.
Exam Tip: In "fill in the blanks," ensure your spelling is perfect as these are technical terms.

Question 2: Pressure difference causes horizontal movement of air called wind and vertical movement of air called current.
Answer: wind, current.
Air always moves from areas of high pressure to low pressure to find a balance. Horizontal travel is what we feel as a breeze, while vertical travel builds clouds.
Teacher's Tip: Think of "Wind" like walking on the ground and "Current" like riding an elevator.
Exam Tip: Don't mix them up: Wind = Side-to-side; Current = Up-and-down.

Question 3: Humidity refers to the amount of moisture or water vapour present in the air.
Answer: water vapour.
Humidity is why some days feel "sticky" even if it isn't raining. It represents the invisible water gas that is always mixed with the air around us.
Teacher's Tip: Higher temperature air can hold more water vapour than colder air.
Exam Tip: Use the phrase "moisture in the air" if you forget the technical term "water vapour."

Question 4: Planetary winds are also called permanent or prevailing winds.
Answer: prevailing.
These winds blow across large parts of the planet in the same direction throughout the year. Examples include the Trade Winds and the Westerlies.
Teacher's Tip: "Planetary" means they affect the whole planet, like big permanent rivers of air.
Exam Tip: Remember that "permanent," "planetary," and "prevailing" all describe the same types of wind.

Question 5: The amount of cloud cover in the sky is expressed in discs (shaded in different proportions).
Answer: discs.
Meteorologists use small circles on maps to show how much of the sky is hidden by clouds. A fully shaded circle means a completely overcast day.
Teacher's Tip: Think of these discs as a "pie chart" of the sky above you.
Exam Tip: Note that these discs are often divided into eight parts called "oktas."

C. Answer the following questions in brief.

Question 1: What are the elements that determine weather and climate?
Answer:
The elements that determine climate are the same as those weather, namely temperature, atmospheric pressure, humidity, precipitation, wind direction and speed, cloud cover, and sunshine.
These building blocks tell us exactly what is happening in the atmosphere at any moment. By tracking these over many years, scientists can define the climate of a whole country.
Teacher's Tip: Remember the main ones: Temp, Rain (Precipitation), and Wind.
Exam Tip: List at least five elements to ensure you cover the whole range for full marks.

Question 2: Name the factors that determine the temperature at a place.
Answer:
The factors that affect the temperature of a place are latitude, altitude, distance from the sea, ocean currents, winds, cloud cover, and slope and aspect.
Each of these factors can make a place feel warmer or colder regardless of the season. For instance, being high up in the mountains (altitude) always leads to lower temperatures.
Teacher's Tip: Distance from the equator (latitude) is usually the most important factor.
Exam Tip: If the question is worth 3 marks, list 3-5 factors clearly.

Question 3: How do the following elements influence the weather of a place : 1. temperature 2. pressure?
Answer:
1. Temperature : When the temperature of a place increases, the air gets heated, expands and rises. This leads to a decrease in air pressure in the area. When the temperature falls, the air gets cold, contracts, and descends downwards. This leads to an increase in air pressure. Thus, air pressure decreases with an increase in temperature. This is the reason why areas close to the equator generally have low air pressure.
2. Pressure : Atmospheric pressure is the pressure that the atmopshere exerts on the surface of the earth because of its weight. There is a close relationship between pressure and temperature - high temperature means low pressure and vice versa. Pressure difference causes horizontal movement of air called wind and vertical movement of air called current, which together cause circulation of air in the atmosphere.
Temperature and pressure act like a teeter-totter; when one goes up, the other tends to go down. This constant shifting is what drives the wind and creates weather patterns like storms or clear skies.
Teacher's Tip: "Hot air rises, Cold air sinks" - this is the golden rule of weather!
Exam Tip: Use the phrase "inverse relationship" to describe how temperature and pressure work against each other.

Question 4: Name the various forms of precipitation.
Answer:
Rain, drizzle, snow, sleet, and hail are all different forms of precipitation.
Precipitation is any form of water that falls from clouds to the Earth's surface. Whether it is liquid or solid depends on the temperature of the air it falls through.
Teacher's Tip: Think of "Precipitation" as the general name for "things falling from clouds."
Exam Tip: Be sure to include both liquid (rain) and solid (snow, hail) forms in your list.

Question 5: How is cloud cover shown on a weather map? Give examples.
Answer:
The cloud cover in the sky is expressed in eighths of the total sky or oktas, which are shown in weather maps as discs shaded in different proportions.
For example, a disc that is half-shaded represents a sky that is half-covered with clouds. This visual shorthand allows people to quickly see weather conditions across a large region.
Teacher's Tip: Imagine looking at a pizza cut into 8 slices; each slice represents one "okta" of cloud.
Exam Tip: Use the specific term "oktas" when describing the measurement of cloud cover.

D. Answer the following questions in one or two paragraph’s.

Question 1: How is weather different from climate?
Answer:
Weather and climate are closely related terms but have different meanings. Weather refers to the atmospheric conditions of a small area for a short period of time, usually 24 hours or one day, while climate is the average of the atmospheric conditions of a larger area, over a long period of time, usually 35 years.
Weather is what you decide to wear today, while climate is the collection of clothes you have in your wardrobe for the whole year. Understanding both helps us prepare for immediate storms and long-term environmental changes.
Teacher's Tip: Weather tells you what is happening "now," climate tells you what to "expect."
Exam Tip: Highlight the "time" difference (1 day vs 35 years) as the main point of contrast.

Question 2: What is condensation? Explain these different forms of condensation: fog, mist, and dew.
Answer:
Condensation is the process by which water vapour in the air gets converted into tiny droplets of water or ice. It is the opposite of evaporation. Evaporation takes place when air is dry, but condensation occurs only after air is saturated.
Fog and mist are formed at night, when air cools below its dew point near the earth’s surface. Fog is denser than mist and often dangerous because it reduces visibility. Dew forms in winter when the temperature is very low, but not below 0°.
Condensation turns invisible water gas back into liquid we can see and feel. While fog sits like a thick cloud on the ground, dew appears as small droplets on grass and leaves during chilly mornings.
Teacher's Tip: Saturation is when the air is "full" of water and cannot hold any more, so it starts to condense.
Exam Tip: For "dew," emphasize that the temperature must be low but above freezing (0°C).

Question 3: What do you understand by the term ‘4 o’clock showers’?
Answer:
In regions closer to the equator, the rate of evaporation is very high. Air gets heated because of the high temperature and starts rising in the form of convection currents. As it rises, it expands and cools. The cooling causes condensation, which results in heavy downpours. This rain is accompanied by thunder and lightning and since it mostly occurs around 4 p.m., it is often called the 4 o’ clock showers’.
This phenomenon is very common in tropical rainforests where the sun's heat is intense every morning. By the time students are finishing school, the massive clouds that built up all day finally break into heavy rain.
Teacher's Tip: Think of it as a "daily cycle" of heat, rising air, and afternoon cooling rain.
Exam Tip: Be sure to mention the location (near the equator) and the cause (convection currents).

Question 4: What are planetary winds? Give a brief description of the Westerlies in the northern hemisphere.
Answer:
Planetary winds are also called permanent or prevailing winds as they blow the year round in the same areas. Westerlies blow in the middle latitudes between 30°C and °C latitude, and originate from the high pressure area in the horse latitudes towards the poles. Under the effect of the coriolis force, they become the South Westerlies in the north hemisphere and Northern Westerlies in the southern hemisphere.
These winds are massive global conveyors that help move weather systems from west to east across continents. They play a huge role in the climates of North America and Europe.
Teacher's Tip: Westerlies blow "from the West" - that is how they got their name!
Exam Tip: Mention the specific latitudes (30°C to 60°C) to show precise geographical knowledge.

Question 5: What are local winds? Give a few examples.
Answer:
Local Winds blow for a short period of time over a very small area. Some local winds like Loo, Simoom, Chinook, and are warm winds. Others such as the Bora, Mistral, Buran, and Pampero are cold winds.
These winds are created by local features like mountains, valleys, or the difference in heating between land and sea. They are usually named by the people who live in those regions because they affect daily life so much.
Teacher's Tip: Think of local winds as "neighborhood winds" compared to planetary "global winds."
Exam Tip: Name at least one hot (Loo) and one cold (Mistral) example to show a complete understanding.

E. With the help of your atlas,encylopaedias, and the Internet, find out about the climate of these places.

1. Mumbai
2. Delhi
3. Kolkata
4. London
5. New York
6. Sydney
Answer:
(Student research project. Example findings: Mumbai has a tropical wet and dry climate. London has a temperate oceanic climate with cool summers and mild winters.)
Looking at these cities shows how latitude and distance from the sea change everything. While Mumbai stays warm all year, New York experiences four very distinct seasons including snowy winters.
Teacher's Tip: Use a world map to see how far each city is from the Equator to guess its climate.
Exam Tip: For project work, always cite your sources like the specific website or book you used.

F. In your notebook, draw neat, labelled, coloured sketches of the three different types of rainfall. Alongside each diagram, briefly describe in your own words, how each type of rainfall occurs.

Answer:
(a) Convectional Rainfall : In regions closer to the equator, the rate of evaporation is very high. Air gets heated because of the high temperature and starts rising in the form of convection currents. As it rises, it expands and cools. The cooling causes condensation, which results in heavy downpours. This rain is accompanied by thunder and lightning and since it mostly occurs around 4 p.m., it is often called the 4 o’clock showers’.
(b) Relief or Orographic Rainfall : Sometimes moisture-bearing winds are forced to rise because of the presence of a physical barrier, such as a mountain, in their path. Such winds expand and cool as they rise up the slope of the mountain or plateau, and on further cooling form clouds. When saturated, these clouds give rain.
(c) Cyclonic or Frontal Rainfall - This type of rainfall occurs when warm and cold air masses meet and form a front. As cold air is denser, it remains close to the ground, while the warm air rises above it. As the warm air rises, it expands and cools, and the moisture in it condenses to form clouds. These clouds bring rainfall.
Rainfall is simply water falling, but the "reason" it was pushed up into the cold sky is what makes these three types different. Whether it is heat, a mountain, or a meeting of air masses, the result is the same: cooling, clouds, and rain.
Teacher's Tip: Think: Heat = Convection, Mountain = Relief, Air Meeting = Cyclonic.
Exam Tip: When drawing diagrams, always use arrows to show the direction of rising air and label the "Windward" and "Leeward" sides for Relief rain.

G. Picture study

Question 1: The diagram alongside illustrates one of the factors that affect temperature. What is it ?
Answer:
Aspect refers to the direction of a slope with respect to the sun’s rays. In the northern hemisphere, all the south-facing slope receive the direct rays of the sun and are, therefore, warmer, while the north-facing slopes are cooler. In the southern hemisphere, all the north-facing slopes receive more sunlight than the south-facing slopes.
The angle at which the sun hits a hill determines how much energy is absorbed by the ground. This is why you might see snow melting much faster on one side of a mountain than the other.
Teacher's Tip: Imagine holding a flashlight: pointing it straight at a surface is much brighter (warmer) than pointing it at a steep angle.
Exam Tip: Be sure to specify the "hemisphere" in your answer, as the "warm side" flips between North and South.

Question 2: Which side of the mountain is likely to have houses and be covered with trees ?
Answer:
SideB.
Side B receives more direct sunlight, making it warmer and better for growing plants and building homes. Warmth and light are essential for life, so people and nature prefer the sunny side of the slope.
Teacher's Tip: "B" is for "Better" living conditions because of the sun!
Exam Tip: Support your choice with a reason, such as "because it receives more direct solar radiation."