Understanding the Weather Class 7 Social Science Chapter 2- CBSE Notes 2025-26

Weather describes the atmospheric conditions of a place at a particular time. It affects everything—from the clothes you choose to the crops that grow in your region. 

The main elements of weather are temperature, precipitation, atmospheric pressure, wind, and humidity. Each element can be felt differently depending on where you live, such as feeling cold in Chennai might not be the same as in Kashmir.

What is Weather? The Earth's atmosphere is a layer of gases, and the bottom-most layer is called the troposphere. This is where we live, and where almost all weather events happen. 

The troposphere is thicker at the equator (up to 18 km) and thinner at the poles (about 6 km). We use words like hot, chilly, humid, or windy to describe the weather, and different cultures have their own ways of expressing these feelings.

Elements of Weather The key elements of weather include:

• Temperature: How hot or cold the atmosphere is.
• Precipitation: Rain, snow, sleet or hail that falls from the sky.
• Atmospheric pressure: The force of air pressing down on Earth's surface.
• Wind: Movement of air; both speed and direction matter.
• Humidity: The amount of water vapour present in the air.

People have always observed signs in nature to predict the weather—watching bird flights, ant movements, or the opening of pine cones. Nowadays, weather is measured with scientific instruments, and these observations help meteorologists make predictions that can save lives and property.

Measuring Temperature Temperature is measured using thermometers. The Celsius and Fahrenheit scales are both common; for example, 15°C equals 59°F. Maximum and minimum thermometers track daily variations, while digital thermometers provide accurate readings for modern needs. Important terms include:

• Range of temperature: Difference between the day’s highest and lowest temperatures.
• Mean daily temperature: The average of maximum and minimum temperatures for a day.

Measuring Precipitation Rainfall is measured with a rain gauge. If a place receives 30 mm rainfall in a day, it means that 30 millimetres of rainwater collects on a flat surface. Students can build simple rain gauges and measure rainfall every day to analyse patterns in their locality.

Atmospheric Pressure and Its Measurement Atmospheric pressure tells us how heavy the air above us is. It is measured using a barometer. Normal atmospheric pressure at sea level is about 1013 millibars (mb). As altitude increases, pressure drops, which is why mountaineers may feel breathless. A pressure below 1000 mb often signals storms or cyclones.

Measuring and Understanding Wind Wind moves from areas of high pressure to low pressure. Two main instruments help us:

• Wind vane: Shows wind direction. Commonly seen on buildings or airport runways (wind socks).
• Anemometer: Measures how fast the wind blows in kilometres per hour (km/h).

Humidity Humidity is the water vapour in the air. It is measured in percentage as relative humidity. Dry weather may have 20–40% relative humidity, while humid conditions range from 60–80%. A hygrometer is the instrument used to record these values. High humidity slows drying of wet clothes and increases sweating.

Weather Stations and Automated Systems A weather station keeps all these instruments at one place to measure temperature, rainfall, pressure, wind and humidity. Data collected over time help in mapping and forecasting the weather. 

Today, Automatic Weather Stations (AWS) use electronic sensors and send data directly, even from remote areas such as high-altitude lakes in Sikkim.

Predicting Weather and Warnings Meteorologists collect weather data over many years. They use it to predict conditions like drought, floods or cyclones. Timely warnings, like heat waves or heavy rain alerts, help people and local authorities get ready and avoid disasters.

Summary Table: Weather Instruments and Elements

Weather forecasts are essential for farmers, sailors, and even families planning outings. They guide us in making day-to-day decisions and prepare us for extreme situations. Weather and climate are deeply linked, and understanding weather is a key step toward understanding broader climate patterns.

Class 7 Social Science Chapter 2 Notes – Understanding the Weather: Key Points for Quick Revision

These Class 7 Social Science Chapter 2 notes make it easy to remember the main points about weather and its measurement. With clear explanations of terms like temperature, precipitation, and humidity, students can quickly revise before exams. The concise tables and examples help link real-life experiences with important weather concepts.

All key elements—like atmospheric pressure, wind, and the use of weather instruments—are covered in these revision notes for CBSE Class 7 SST. Students can review definitions, summary tables, and question formats, making their preparation more effective and boosting confidence for assessments.