Class 6 Science

Here you can find Class 6 Science Notes. These notes include important revision points, simple explanations of “Curiosity”

Chapter 1. The Wonderful World of Science

This chapter explains that science is the study of the natural world that helps us understand how various things happen around us. We use science when we observe our surroundings, ask questions, and perform experiments to find clear and reliable answers. From ancient times, humans have used scientific thinking to make life better. Early humans discovered fire, invented simple tools, and learned farming by observing nature. As time passed, science led to great inventions such as the wheel, electricity, machines, medicines, and modern communication devices, all of which have made our lives more comfortable and efficient.

Key Points

• Science is the systematic study of the natural world through observation, questioning, and experiments.

•  It helps us understand phenomena like day and night, seasons, rain, growth of plants, electricity, magnets, etc.

•  Early humans used observation and experience to survive (fire, tools, farming).

•  Scientific inventions (wheel, electricity, medicines, communication, machines) have transformed human life.

•  Science is not only about facts but also about curiosity, asking “why” and “how.”

•  Branches of science: Physics (matter, energy, motion), Chemistry (materials, substances), Biology (plants, animals, humans).

•  Technology applies science in practical life—mobiles, computers, transport, medicines, agriculture, etc.

•  Science improves quality of life but must be used responsibly to avoid pollution, overuse of resources, and harmful technologies.

•  Curiosity, questioning, and critical thinking are the first steps toward learning science.

👉 👉Science begins with curiosity. By asking questions and exploring answers, we can improve life, but we must use science wisely and responsibly for the good of people and nature.

Chapter 2. Diversity in the Living World 

This chapter explains that Earth is home to a great variety of living organisms, known as diversity. Living beings differ in their size, shape, colour, structure, habits, and ways of living. Plants, animals, and microorganisms all play important roles in nature—plants provide food and oxygen, animals show diversity in body coverings, food habits, and movement, while microorganisms can be both useful and harmful. To study this vast variety easily, organisms are classified based on similarities and differences. Living beings have special features called adaptations that help them survive in their specific habitats such as deserts, forests, oceans, and polar regions. The chapter highlights that biodiversity is essential for maintaining balance in nature and supporting life on Earth by providing food, medicines, clothing, and other resources.

Key Points

• The Earth is full of a wide variety of plants, animals, and microorganisms—this variety is called diversity.

• Living organisms differ in shape, size, colour, structure, and way of living.

• Plants: Provide food, oxygen, medicines, wood, and shelter.

• Animals: Differ in body coverings (hair, scales, feathers), food habits (herbivores, carnivores, omnivores), and movement (flying, walking, swimming).

• Microorganisms: Tiny organisms not visible to the naked eye. Some are useful (yeast in bread, bacteria in curd) while some are harmful (cause diseases).

• Classification: Grouping of living organisms based on similarities and differences to study them easily.

• Adaptation: Special features that help living beings survive in their surroundings (camel in desert, fish in water, cactus in dry areas).

• Habitats: Natural homes of organisms such as forests, deserts, oceans, rivers, mountains, and polar regions.

• Importance of diversity: Keeps balance in nature, provides food, clothing, medicines, and raw materials, and ensures survival of life on Earth.

👉 👉The beauty of our planet lies in its diversity. We must respect, conserve, and protect all forms of life to maintain balance in nature and ensure a healthy future. 

Chapter 3. Mindful Eating – A Path to a Healthy Body

This chapter explains the importance of food in providing energy, supporting growth, and maintaining good health. It highlights the need for a balanced diet, which includes all essential nutrients such as carbohydrates, proteins, fats, vitamins, minerals, fibre, and water. Carbohydrates are the main source of energy, proteins help in growth and repair of the body, and fats provide energy and keep the body warm. Vitamins and minerals protect the body from diseases, while fibre (roughage) aids in digestion and keeps the stomach clean. Water is essential for digestion, circulation, and removal of waste. The chapter also warns that junk food and overeating can harm health and cause obesity and diseases. It emphasizes mindful eating, which means eating fresh, clean, nutritious food, chewing properly, eating at regular times, and avoiding wastage. Along with good food habits, exercise, and hygiene, mindful eating leads to a healthy life. 

Key Points

• Food gives us energy to work, grow, and stay healthy.

• A balanced diet includes all nutrients: carbohydrates, proteins, fats, vitamins, minerals, fibre, and water.

• Carbohydrates – Main source of energy (rice, wheat, potatoes).

• Proteins – Help in growth and repair of body (milk, pulses, eggs, fish).

• Fats – Provide energy and keep the body warm (oil, ghee, nuts).

• Vitamins & Minerals – Protect from diseases and keep body functions healthy (fruits, vegetables, milk).

• Fibre (roughage) – Helps in digestion and keeps the stomach clean (fruits, vegetables, whole grains).

• Water – Essential for digestion, circulation, and removal of waste.

• Junk food and overeating harm health, causing obesity and diseases.

• Mindful eating means eating fresh, clean, nutritious food, chewing properly, avoiding wastage, and eating at regular times.

• Good food habits + exercise + hygiene = healthy life.
   

👉 👉Healthy eating builds a healthy body and mind. We should eat balanced food, avoid junk, exercise regularly, and respect food by not wasting it. 

Chapter 4. Exploring Magnets 

This chapter introduces magnets and their special properties. Magnets attract certain materials such as iron, nickel, and cobalt, but do not attract wood, plastic, or aluminium. Every magnet has two poles—the North Pole and the South Pole—where the force of attraction is strongest. The chapter explains that like poles repel each other while unlike poles attract each other. A freely suspended magnet always aligns itself in the north–south direction, which is the principle used in a compass. Magnets can be natural like lodestone or artificial such as bar, horseshoe, and cylindrical magnets. They have many uses in daily life, including compasses, fridge doors, toys, cranes, motors, and speakers. The chapter also explains that magnets can lose their magnetic strength if heated, hammered, or dropped, and therefore must be stored properly with keepers to maintain their strength. 

Key Points

• Magnets attract materials like iron, nickel, and cobalt; they do not attract wood, plastic, or aluminium.

• A magnet has two poles – North Pole (N) and South Pole (S).

• Like poles repel each other (N–N, S–S), unlike poles attract each other (N–S).

• Every magnet, if freely suspended, aligns itself in the north–south direction.

• Magnets can be natural (lodestone) or artificial (bar, horse-shoe, cylindrical).

• Uses of magnets: compass, fridge doors, toys, cranes (lifting heavy iron), motors, speakers.

• Magnets lose their property if heated, hammered, or dropped hard.

• Magnetism can pass through non-magnetic materials like paper, cloth, or wood.

• Magnets are useful in daily life but should be stored properly with keepers (soft iron bars) to avoid losing strength.  
   

👉 👉Magnets are powerful and useful in many ways. We should handle them carefully, store them properly, and use their properties for solving problems in daily life. 

Chapter 5. Measurement of Length and Motion 

This chapter explains the importance of measurement in finding the size, length, or amount of objects using standard units. In earlier times, people used non-standard units such as hand span, footstep, and cubit, which were not accurate or reliable. To ensure uniformity, the metre (m) was introduced as the standard unit of length, with centimetre (cm) and millimetre (mm) as smaller units and kilometre (km) as a larger unit. The chapter describes different measuring instruments like rulers, measuring tapes, and metre rods, and stresses the need for correct measurement techniques to avoid parallax error. It also introduces the concept of motion, defined as a change in position with time, and explains various types of motion such as rectilinear, circular, periodic, and rotational motion. The chapter concludes by stating that rest and motion are relative, as the same object may appear at rest or in motion depending on the observer. 

Key Points

• Measurement means finding the size, length, or amount of something using standard units.

• Earlier, people used non-standard units (hand span, footstep, cubit), but they were not reliable.

• Standard unit of length = metre (m). Smaller units = centimetre (cm), millimetre (mm). Larger unit = kilometre (km).

• Instruments for measuring length: ruler/scale, measuring tape, metre rod, vernier caliper (higher classes).

• To measure correctly, keep the scale straight and eye at level with the marking to avoid parallax error.

• Motion means change in position of an object with time.

• Types of motion:

– Rectilinear motion – Straight line motion (train on track).

– Circular motion – Around a circle (hands of a clock).

– Periodic motion – Repeats after equal intervals (pendulum).

– Rotational motion – Spinning around an axis (top, Earth).

• Rest and motion are relative – the same object may appear at rest to one observer but in motion to another.
   

👉 👉Accurate measurement and understanding of motion are essential in science and daily life. Using standard units helps us compare and share results reliably. 

Chapter 6. Materials Around Us

This chapter explains that we use a wide variety of materials in our daily life such as wood, plastic, metal, glass, rubber, paper, cotton, and wool. These materials differ in their properties, including appearance (shiny or dull), hardness (hard or soft), solubility (soluble or insoluble in water), transparency (transparent, translucent, or opaque), floatation (floating or sinking in water), and conduction of heat and electricity. Metals are good conductors, while wood, rubber, and plastic act as insulators. The chapter highlights that materials are selected based on their properties and the purpose they serve, such as glass for windows, metal for utensils, and plastic for bottles. It also emphasizes the importance of the proper use and recycling of materials to reduce waste and protect the environment. 

Key Points

• We use different materials in daily life – wood, plastic, metal, glass, rubber, paper, cotton, wool, etc.

• Materials differ in properties such as:

– Appearance: shiny (metals) or dull (wood, clay).

– Hardness: hard (iron, stone) or soft (cotton, rubber).

– Solubility: some substances dissolve in water (salt, sugar) while others do not (sand, oil).

– Transparency: transparent (glass, water), translucent (butter paper), opaque (wood, metal).

– Floatation: some materials float (wood, plastic) while others sink (stone, iron).

– Conduction: metals conduct heat and electricity; wood, rubber, and plastic do not.

• Materials are chosen based on their properties and the purpose they serve (example: glass for windows, metal for utensils, plastic for bottles).

• Proper use and recycling of materials reduces waste and protects the environment.  
   

👉 👉Every material has unique properties. By choosing the right material for the right purpose and reusing or recycling them, we can live wisely and care for nature. 

Chapter 7. Temperature and Its Measurement 

This chapter  explains that temperature tells us how hot or cold an object is. It is measured in degrees Celsius (°C) using a thermometer. The chapter describes two main types of thermometers: the clinical thermometer, used to measure human body temperature (normal temperature 37°C or 98.6°F), and the laboratory thermometer, used in experiments to measure a wider range of temperatures. It highlights important precautions while using a thermometer, such as holding it upright, reading it at eye level, and not touching the bulb, to avoid parallax error. The chapter also explains that heat always flows from a hotter body to a colder body until both reach the same temperature. It clearly distinguishes between heat, which is a form of energy, and temperature, which is the degree of hotness or coldness. Finally, it explains that thermometers work on the principle of expansion of mercury or alcohol when heated. 

Key Points

• Temperature tells us how hot or cold an object is.

•  It is measured in degrees Celsius (°C) using a thermometer.

• Clinical thermometer: measures human body temperature (range 35°C – 42°C). Normal body temperature = 37°C (98.6°F).

• Laboratory thermometer: used in experiments (range –10°C to 110°C).

• Precautions while using a thermometer:
  – Hold upright, not tilted.
  – Read at eye level.
  – Do not touch bulb while measuring.
  – Shake clinical thermometer before use to bring mercury below 35°C.

• Heat flows from a hotter body to a colder body until both reach the same temperature.

• Difference between heat and temperature:
  – Heat = form of energy.
  – Temperature = degree of hotness or coldness.

• Thermometers work on the expansion of mercury or alcohol with heat.
   

👉 👉Temperature helps us understand and compare hotness or coldness. Measuring it correctly ensures safety, health, and accuracy in science. 

Chapter 8. A Journey through States of Water 

This chapter explains that water exists in three different states—solid (ice), liquid (water), and gas (water vapour or steam). The chapter describes the change of state of water due to temperature changes, such as melting (ice to water), evaporation/boiling (water to vapour), condensation (vapour to water), and freezing (water to ice). It introduces the water cycle, which is the continuous movement of water in nature through evaporation, condensation, and precipitation. The chapter also explains that evaporation becomes faster with an increase in temperature, surface area, and wind speed, while condensation leads to the formation of dew, fog, and clouds. Water is shown to play a vital role in weather, climate, and life on Earth. The chapter highlights that human activities like pollution, wastage, and deforestation disturb the natural water cycle, making water conservation essential through methods such as rainwater harvesting, reducing wastage, and reusing water. 

Key Points

• Water exists in three states –

– Solid (ice)

– Liquid (water)

– Gas (water vapour or steam).

• Change of state: Water can change from one form to another with temperature changes:

– Ice → Water = Melting

– Water → Vapour = Evaporation/Boiling

– Vapour → Water = Condensation

– Water → Ice = Freezing

• The water cycle is the continuous movement of water in nature through evaporation, condensation, and precipitation.

• Evaporation is faster when temperature, surface area, or wind speed increases.

• Condensation forms dew, fog, and clouds.

• Water plays a vital role in weather, climate, and maintaining life on Earth.

• Human activities like pollution, wastage, and deforestation disturb the natural water cycle.

• Conservation of water is essential—methods include rainwater harvesting, reducing wastage, and reusing water. 

👉 👉Water constantly changes its form but remains the same precious resource. We must value, save, and use it wisely for a sustainable future. 

Chapter 9. Methods of Separation in Everyday Life 

This chapter explains how we often need to separate useful substances from unwanted materials in our daily life. Many things around us are mixtures, which contain two or more substances physically mixed together, such as rice and stones or salt and sand. The chapter describes different methods of separation, chosen based on the properties of substances like size, weight, solubility, and state. Simple methods include hand picking, threshing, winnowing, and sieving, while other techniques such as sedimentation, decantation, filtration, evaporation, and condensation are used to separate solids from liquids or obtain pure substances. These methods help in cleaning materials, removing impurities, and making substances suitable for use. The chapter highlights that separation is an important process that makes everyday tasks easier and more efficient. 

Key Points

• In daily life, we often need to separate useful and unwanted substances from mixtures.

• A mixture contains two or more substances physically combined (e.g., salt and sand, rice and stones).

• Different methods of separation are used depending on the type of mixture and purpose:
  – Hand picking – Removing impurities by hand (e.g., stones from rice).
  – Threshing – Separating grains from stalks after harvesting.
  – Winnowing – Using wind to separate lighter and heavier substances (e.g., husk from grains).
  – Sieving – Using a sieve to separate particles of different sizes (e.g., flour and husk).
  – Sedimentation and Decantation – Settling heavy solids at the bottom and pouring out clear liquid.
  – Filtration – Using filter paper or cloth to separate insoluble solids from liquids (e.g., mud from water).
  – Evaporation – Removing water from a solution by heating (e.g., obtaining salt from seawater).
  – Condensation – Cooling vapour to obtain liquid back (used in distillation).

• Separation helps in obtaining pure substances, cleaning materials, and removing unwanted parts.

• Each method is chosen based on the properties of substances like size, weight, solubility, and state.

👉 👉Separation of substances is a smart way to make materials useful and clean. Understanding and applying the right method saves time, effort, and resources in everyday life. 

Chapter 10. Living Creatures – Exploring Their Characteristics 

This chapter explains the key features of living beings that distinguish them from non-living things. All living creatures show growth, movement, respiration, nutrition, and excretion, which are essential for survival. They also have the ability to respond to stimuli, such as reacting to heat, light, or touch, and can reproduce to produce offspring of their own kind. Living beings develop special adaptations that help them survive in their environment, and each has a definite life span. The chapter highlights differences between plants and animals in terms of movement, nutrition, and habitat adaptations, while emphasizing that these life processes are absent in non-living things. 

Key Points

• All living creatures share certain basic characteristics that distinguish them from non-living things.

• Main characteristics of living beings:
  – Growth: Living things grow in size and shape naturally (e.g., plants grow taller, humans grow from babies to adults).
  – Movement: All living beings show movement; animals move from place to place, plants show movement in parts (e.g., sunflower facing the sun).
  – Respiration: Living organisms take in oxygen and give out carbon dioxide to release energy.
  – Nutrition: All living things need food for energy and growth.
  – Excretion: Removal of waste materials from the body (e.g., humans excrete urine and sweat).
  – Response to Stimuli: Living beings respond to changes in surroundings (e.g., withdrawing hand from a hot surface, touch-me-not plant closing leaves).
  – Reproduction: Living beings produce their own kind (offspring).
  – Adaptation: Adjusting to environment for survival (e.g., fish have gills to breathe in water).
  – Life Span: Every living thing has a definite period of life.

• Non-living things do not grow, reproduce, or respond to stimuli on their own.

• Plants and animals differ in their mode of nutrition, movement, and habitat adaptations.

👉 👉All living beings are special and interconnected. Understanding their characteristics helps us respect and care for every form of life on Earth. 

Chapter 11. Nature’s Treasures  

This chapter explains that nature provides many valuable natural resources that are essential for life on Earth. These treasures include air, water, soil, sunlight, plants, animals, and minerals, which help meet our basic needs such as food, water, shelter, energy, and raw materials. The chapter classifies natural resources into renewable resources, which can be replenished naturally like sunlight, wind, water, and forests, and non-renewable resources, which are limited and take millions of years to form, such as coal, petroleum, natural gas, and minerals. It highlights the importance of these resources in maintaining ecological balance and supporting biodiversity. The chapter also warns that human activities like deforestation, over-mining, and pollution are rapidly depleting nature’s wealth. Therefore, conservation through avoiding wastage, reducing pollution, following the 3Rs—Reduce, Reuse, Recycle, promoting afforestation, protecting wildlife, and using renewable energy sources is essential to ensure a sustainable future for future generations. 

Key Points

• Nature’s treasures refer to all valuable resources provided by nature that support life on Earth.
  • These include air, water, soil, sunlight, plants, animals, and minerals.

• Natural Resources are classified as:
  – Renewable resources: Can be replenished naturally (e.g., sunlight, wind, water, forests).
  – Non-renewable resources: Limited in quantity and take millions of years to form (e.g., coal, petroleum, natural gas, minerals).

• Importance of Natural Resources:
  – Provide food, water, shelter, energy, and materials for living beings.
  – Maintain ecological balance and support biodiversity.

• Conservation of Nature’s Treasures:
  – Avoid wastage and pollution of natural resources.
  – Promote 3Rs: Reduce, Reuse, Recycle.
  – Encourage afforestation and protection of wildlife.
  – Use energy sources like solar and wind power to reduce dependency on fossil fuels.

• Human activities such as deforestation, over-mining, and pollution are depleting nature’s resources rapidly.

• Protecting these treasures ensures a sustainable future for upcoming generations.

👉 👉Nature’s treasures are the foundation of life. We must respect, protect, and use them wisely to preserve the planet for all living beings. 

Chapter 12. Beyond Earth 

This chapter explains that Earth is a part of the vast universe, which contains billions of stars, planets, and galaxies. It introduces the Solar System, our cosmic neighbourhood, made up of the Sun, eight planets, their moons, and other celestial bodies such as asteroids, comets, and meteoroids. The Sun, a huge star at the centre of the Solar System, provides essential light and heat that support life on Earth. The chapter lists the eight planets in order from the Sun and explains why Earth is the only known planet with life, due to its water, oxygen-rich atmosphere, and moderate temperature. It also describes the Moon as Earth’s only natural satellite, explaining its phases and its effect on ocean tides. The role of artificial satellites in communication, weather forecasting, navigation, and research is highlighted. Finally, the chapter introduces different astronomical bodies and explains how space exploration helps scientists study the mysteries of the universe using rockets, telescopes, and spacecraft. 

Key Points

• Earth is a part of the vast universe, which contains billions of stars, planets, and galaxies.

• The Solar System is our cosmic neighbourhood, consisting of the Sun, eight planets, moons, and other celestial bodies like asteroids, comets, and meteoroids.

• The Sun is a star at the centre of the Solar System — it provides light and heat that support life on Earth.

• The Eight Planets (in order from the Sun): Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

• Earth is the only known planet with life — due to its oxygen-rich atmosphere, moderate temperature, and presence of water.

• The Moon is Earth’s only natural satellite — it reflects sunlight and affects tides in oceans.
  – It takes about 27 days to orbit Earth.
  – Phases of the Moon: New Moon → Crescent → Half Moon → Full Moon.

• Artificial satellites are man-made objects that revolve around Earth for communication, weather forecasting, navigation, and research.

• Astronomical bodies:
  – Stars: Huge, glowing balls of gases that emit light.
  – Planets: Do not produce light; reflect sunlight.
  – Comets: Made of ice and dust; appear with glowing tails.
  – Asteroids: Rocky bodies orbiting between Mars and Jupiter.

• Space exploration is carried out by scientists using rockets, telescopes, and spacecraft to study celestial bodies.

👉 👉The universe is vast and full of mysteries. Exploring space helps us understand our place in it and inspires curiosity about the wonders beyond Earth.