Sun as a Natural Resource Chapter Notes | Science Class 3 ICSE PDF Download

Introduction

The Sun is a vital natural resource that provides light, heat, and energy, making life possible on Earth. As a star, it is the brightest object in the daytime sky and plays a key role in supporting living things and various processes on our planet. This chapter explores the Sun's importance, its energy, uses, effects on seasons, and the need for energy conservation.

Sun - A Natural Source of Energy

• The Sun is a non-living natural resource.
• It provides solar energy, which is abundant and freely available.
• Solar energy is clean and does not cause pollution.

Importance of Sun for Living Things

• Sunlight is necessary for plants to perform photosynthesis, a process where they use solar energy to produce food.
• Plants store solar energy in their roots, stems, and fruits.
• Humans and animals obtain solar energy indirectly by eating plants or plant-based products.

Uses of Solar Energy

• Plants use sunlight for photosynthesis to create food.
• Solar water heaters use solar energy to heat water.
• Solar roof panels with solar cells convert sunlight into electricity.
• The Sun’s heat dries wet clothes.
• Solar cookers use solar energy to cook food.
• Food items like pickles and chips are made by drying in the sun.
• Solar energy is used in agriculture for various tasks.
• Grains are dried in the sun to preserve them for longer storage.
• Solar energy helps produce salt from seawater, an ancient practice.
• Solar energy aids in evaporating water, contributing to the water cycle.
• Common uses include cooking, charging batteries, heating homes, and heating water.

Effect of Sun on Seasons

• The Sun’s heat and light warm the Earth’s surface, causing changes in weather.
• The Earth’s movement around the Sun changes the amount of sunlight different regions receive daily.
• These sunlight changes cause seasons like summer, monsoon, winter, spring, and autumn.
• People choose clothing and food based on the season.

Sources of Energy

• Energy sources are resources that provide energy, classified as renewable or non-renewable.
• Renewable energy sources are abundant and can be used repeatedly.
• Examples of renewable energy sources:
  • Solar energy: Energy from the Sun.
  • Wind energy: Energy from moving air, used to power windmills in large fields.
  • Hydroelectric energy: Energy from running water, captured by dams on rivers.
• Renewable energy sources are used to produce electricity.
• Non-renewable energy sources are limited and cannot be replenished once used.
• Examples of non-renewable energy sources: Coal, Petroleum & Natural gas.

Conservation of Energy

Energy conservation means saving energy by reducing its use and avoiding wastage. Non-renewable energy sources are limited, so they must be used carefully.
Ways to conserve energy:

• Use daylight instead of electric lights during the day.
• Turn off fans and lights when not in use.
• Use LED bulbs and tubes, which save energy and last longer.
• Keep the refrigerator door closed to save energy.
• Run full loads in dishwashers and washing machines.
• Dry clothes in the sun instead of using a dryer.
• Walk or use public transport for short distances.
• Use natural gas for cooking.
• Use renewable energy sources like solar and wind energy to reduce reliance on non-renewable sources.

Terms to Know

• Resource: Something available for use.
• Natural resource: Useful things found naturally in the environment.
• Sources of energy: Resources that provide energy.
• Renewable sources of energy: Energy sources that can be used repeatedly.
• Non-renewable sources of energy: Energy sources that are limited and cannot be replenished.
• Solar Energy: Energy obtained from the Sun.
• Wind Energy: Energy obtained from moving air.
• Hydroelectric Energy: Energy obtained from running water.
• Conservation of Energy: Saving energy by reducing its use and wastage.