Learning Objectives1. Water is a natural resource.2. Water cycle.3. Role of transpiration, evaporation, vaporization in water cycle.4. Formation of hail, snow, precipitation and rains.5. Sources of water.6. Conservation of water.About three fourth of Earth's surface is covered with water. Water is found inrivers, seas, oceans, soil, air, plants and animals. Man is dependent on plantsand animals which are in turn dependent on air, water and soil etc. All suchsubstances which are used by man for sustenance of life and his welfare arecalled resources and those that are found in nature are called natural resources.Importance of water: Water is the most important substances required byus. Without water, we cannot live. Water is used in agriculture, industries, forwashing, bathing, drinking, cooking, cleaning and several other purposes. Ourbody has 70% water by weight while water melon is 99% water.
Percentage of water in food and animals1. Several life processes like digestion, excretion, absorption of nutrientsand distribution required large quantity of water.2. Water is the natural habitat for marine life.3. Water is a universal solvent as it can dissolve may substances.4. It is used in bathing, cleaning, washing, dyeing and other householdpurposes.5. Water helps in dispersal of seeds and fruits.6. It is used for generating steam in factories.7. It is used in sports and recreation.8. It is also used to generate hydroelectricity.9. It is essential for germination of seeds and for photosynthesis.10. Crops cannot grow without water.11. Our body temperature is controlled by water.12. It is also used as a mode of transportation. more...
Learning Objectives1. Our environment is made up of biotic and abiotic components.2. Main types of habitat are aquatic and terrestrial.3. Desert plants and animals are adapted to reduce loss of wafer.Livings organisms exist in most places. We come across plants and animal se very day.Living things are found practically everywhere. Some live on land, some under water, some in burrows, and some in air. Life exists even in open volcanoes.Some organisms live even in our homes.Do You KnowThe word ecology is derived from Greek word ’Oikos’ which means ‘house’ or ‘place to live in’ German Biologist Ernst Haeckel was first one to use this word. HABITATThe term habitat refers to the surroundings where organisms live. Every habitats home for a certain living creature. Habitat includes both living and non-living components. Plants and animals have different features that help them to survive in their own habitat. Habitat can be terrestrial or aquatic.Importance of habitatsA good habitat provides its inhabitants the following:1. A suitable place for organisms to stay and rest.2. It makes enough food available.3. Provides protection to the in habitants.4. Provides place for breeding and rearing of organisms.5. Provides space for movement.Terrestrial habitat refers to the land where all plants and animals survive. It includes deserts, forests and grasslands, as well as coastal and mountain regions. For example, camels and cactus plants live in deserts only.Aquatic habitat refers to the water where plants and animals survive. Aquatic habitat includes rivers, ponds, lakes, ocean and swamps. For example, fish live in water.Adaptation: Plants and animals develop certain features or certain habits that help them survive in their surroundings, and this is known as adaption. Different living creatures adapt to their habitats in different ways. For example, fish have gills that help them to live in water and use the oxygen dissolve in it.6. Plants that live in water have special tissues that help to take in dissolved gas from water. For example, the ulva has ribbon-like leaves. It takes thousands of years for a livings being to adapt to its habitat.Acclimatization: The small adjustments by the body to overcome small changes in the surrounding atmosphere for a short period of time are called acclimatization.The components in a habitat are broadly classified into two types. They are biotic and a biotic components.Biotic components include all the livings organisms in a habitat. These can be farther classified into following categories: more...
Learning Objectives1. Locomotion is movement of animals from one place to another.2. Skeleton in humans is made of bones and cartilages.3. Bones are joined to muscles by tendons.4. Where two bones meet the place is called a joint.5. The skull, backbone, shoulder bones, hip bones and ribs form the skeleton system.6. Movements In various organisms like snail, earthworm, fish, snake and birds are different.Living things differ from non-living things in that living things show movements of their body parts. Even when we are at rest our body shows some movements like blinking of eyes. Animals move from one place to another. For this purpose they show various kinds of movements like walking, running, flying, creeping, slithering crawling, etc.Movements: A change in the position of any object is called movement. Many movements take place in our body and also in other organisms' body.Locomotion: When movement results in change of position of the whole organism, it is called locomotion.Examples of Movements in the Human Body:(a) Movement of eyelids.(b) Movement of the heart muscles.(c) Movement of teeth and jaw.(d) Movement of arms and legs.(e) Movements of head.(f) Movements of neck.Movement of some organs happens because of the team work of bones and muscles. In such cases, movement is possible along a point where two or more bones meet.Human body movements: Humans can move their various body parts indifferent ways. We can move some parts of our body in different directions and some body parts can be moved only in one direction. Our body is made up of a frame work of bones called skeleton.1. Bones are made of hard substance.2. Cartilages are soft and elastic.3. In the bone marrow, red blood cells are produced.4. Bones are of many shapes and sizes. Some are flat, some are cylindrical and some are spherical.5. The longest bone of our body is femur and the smallest bone is found in our internal ears.6. Cartilages are found in our nose and external ears.7. Skeleton system extends from the top of our head to the tip of the toes.Functions of skeleton:
The skeleton gives shape to our body.
Skeleton protects many delicate internal organs.
Skeleton provides numerous points for attachment of muscles.
Bones are held together by strands of tissues called ligaments. Points where two bones join are called joints. There are 206 bones in a human body. more...
Learning Objectives1. Plants can be classified into herbs, shrubs and frees.2. A flowering plant has 2 septum -shoot and root septum.3. Roots are of two types-top and fibrous.4. Stem conducts water and minerals. Some stems store food and water.5. Leaf prepares food for the plant by photosynthesis.6. Flower is the reproductive part of the plant.7. Pollination and fertilization result in the formation of fruit.Plants grow all around us. They grow on land as well as in water. There are about 2, 50, 000 types of plants. Carolusinneaus put forward a method of namingliving things and classifying them into groups.Classification of Plants:I. Plants were divided into two broad groups - flowering plants andnon-flowering plants. Flowering plants are rose, mango, sunflower and jasmine, etc. Ferns & mosses are non-flowering plants. II. Based on their life span: Depending on the duration of their life cycle, there are three types of plants: (i) Annuals: The life cycle of these plants is completed in one yearThey grow, produce flowers and seeds during this period and thendie. E.g. wheat, pulses, gram. (ii) Biennials: These plants complete their life cycle in two years. These plants are usually herbs. (iii) Perennials: These remain alive for many years. These are mostlyshrubs and trees. They keep producing flowers, fruits and seeds year after year. E.g. neem, mango. Hibiscus, etc.III. Classification based on the size and nature of stem. Based on nature of stem plants can be grouped into (a) Herbs (b) Shrubs (c) Trees (d) Climbers
Learning Objectives 1. There are 6 nutrients in our food; carbohydrates, fats, proteins, vitamins, minerals and water.2. Deficiency of nutrients leads to deficiency diseases.3. Fiber or roughage is also necessary for our digestive system.4. A balanced diet is necessary to remain healthy.We take food every day, it is the basic necessity of life. Food provides usenergy to work, to grow and protects us from diseases. Proper food keeps us ingood health.The kind of food that we eat, depending on our liking and availability rawfood materials form our food habits. Some people eat wheat based mealswhereas some prefer rice based meals. Some take non-vegetarian food whileothers are vegetarians. However, in spite of the great diversity in the foodhabits of the people, we either consume food that are plant based or come fromanimals sources.FUNCTIONS OF FOOD
Energy giving food: These food items provide energy to our body to dowork. g. sugar, cereals, jiggery, oil fats, starchy vegetables (potato, sweet potato) etc.
Body building food: These food items are growth promoting. g. milk, pulses, meat, egg, fish etc.
Protective food: Food items that protect our body against diseases fallunder this category. E.g. vitamins and minerals present in milk, greenleafy vegetables and fruits.
COMPONENTS OF FOODThe main components of foods are carbohydrates, protein, fats, vitamins andminerals. These are called nutrients.CarbohydratesCarbohydrates are also called energy giving food. It is the main sources of energy It is made up of carbon, hydrogen, and oxygen. There are three types of carbohydrates.(a) Sugars: It is a simple carbohydrate having sweet taste. Sources of sugarare glucose, Sugarcane, milk and fruits; such as banana, apple, grapes, etc.(b) Starch: It is a complex carbohydrate. It is a tasteless, colour less, white power. Sources of starch are : wheat, maize, potato and rice.(c) Cellulose: It is present in plant cell wall. It is a complex carbohydrate.Humans cannot digest cellulose.Children, players and people who do manual work require more carbohydrates.ProteinProtein helps in body growth and repairs the tissues so it is also called bodybuilding food. We get protein from milk, eggs, meat, fish and all kinds ofpulse.Protein molecule is made of a large number of smaller molecules called aminoacid. The daily requirement of protein for adults is 1 gram per kilogram of thebody weight. When the body is building new tissue, more proteins are required, so growing children and pregnant lady more...
Learning Objectives1. Food provides energy and keeps the body fit and healthy.2. We use a variety of ingredients to prepare food.3. Food can be obtained from plants and animals.4. Plant sources are cereals, pulses, fruits, vegetables, oil, seeds, etc.5. Animal sources are milk, egg, meat, fish, etc.6. There are three kinds of animals, herlivores, carnivores and omnivores.7. Each animal is dependent on either plant or another animal for food.8. A series of plants and animals depending on each other forms the food cycle.9. Balance of nutrients in nature is necessary.To keep a car engine running properly, it should be supplied with right amount of fuel and oxygen. Similarly to keep our body working properly, it must be supplied with right amount of right chemicals in food. These chemicalsubstances in food that our body needs is called nutrients.Functions of FoodFood has 3 main functions:It provides energy for various activities of the body.It helps the body to grow and replace old cells.It protects the body from various diseases and keeps it fit and healthy.Different food items containing carbohydrates, fats, proteins, vitamins, minerals, etc. We eat different kinds of food, we eat grains, pulses, vegetables, fruits, fish, eggs, meat and different dairy products. Different food contain different nutrients. Some nutrients help us grow, some give energy and some help income pleating diseases.India is a vast country and people in different regions cook different dishes. A basic dish like boilde rice contain only rice and water. A vegetable pulao/biryani contain rice, vegetables, spices, water, salt and oil. It has number of ingredients. These ingredients come from two sources - plants and animals.Boiled rice has 2 ingredients Vegetable pulao has many ingredients SOURCES OF FOODFood from plants: Green plants prepare their own food with the help of carbon dioxide, water and sunlight by the process of photo synthesis. Greenplants are therefore called producers. They prepare some extra food thanthey need. This extra food is stored in various parts of the plant.Do You KnowRoots of Baobab tree are eaten during faminePLANTS PARTS THAT ARE EATENRoots: We eat roots of carrot, radish, sweet potato and beetroot. In Rajasthan roots of more...
Learning Objectives1. To understand changes around us2. To understand effect of causes of these changes on things around us3. To understand classification of different changes on the basis of their effect4. To understand characteristics of these changes.Every day, we see different types of changes around us, like day turning into night, the season changing from winter to summer, melting of ice to water, cooking of food, rusting of iron .growth of our body and so on.There are number of changes taking place around us -Some of these changes can be noticed immediately, some changes can be noticed after some time and there are some changes that cannot be noticed. Every change has a cause for example day and night alternate because of the rotation of the earth around the sun. Changes in weather is due to the heat of the sun These causes can bring about changes in:Shape and size: There is a change in shape and size of a balloon when air is blown into it.Making of various toys or geometrical figures (such as rectangle, square etc.) using a paper sheet bring about a change in the sheet of paper. The ball of dough takes the shape of a chapati when it is properly rolled.State: Ice melts on heating, melting of butter and ice cream etc.Position: Sun changes its position from east to west due to rotation of the earth around imposition of a football changes on kicking it.Colour: On heating an iron piece it becomes red hot, colour change of silver ornament etc.CLASSIFICATION OF CHANGES 1. Based on SpeedSlow changes: A change that occurs very slowly and takes a very long time for completion is called a slow change.For example
Growth of a child into an adult and then into an old men takes years to occur.
Curdling of milk takes few hours to occur
Germination of seed to form a plant takes 2 -4 days
Ripening of fruits is also a slow change
Conversion of night into day occurs slowly
Cooking food also takes some time.
One complete rotation of the earth around sun takes 24 hours.
Fast changes: A change that occurs spontaneously or occurs at a very fast speed is called a fast change. For example:
Learning Objectives1. To understand mixtures and types of mixture.2. To understand requirement and Importance of separation of components of a mixture.3. To understand different methods of separation.4. To understand that the choice of the method of separation depends upon the nature of the component of the mixture.5. To understand the different types of solution.6. To understand the concept of solubility.MIXTURESMixtures are absolutely everywhere you look. Mixtures are the form that are mostly found in nature e.g. rocks, air, or the ocean they are just about anything you find. They are substances held together by physical forces, not chemical.Two or more substances (either elements or compounds) can be mixed together in any proportion and the resultant substances so obtained are called mixtures (impure substance).Types of MixturesDepending upon the nature of the components that forms the mixture we can have different types of mixtures.(i) Homogeneous mixture: It is a mixture that has the same composition throughout, e.g. a solution of sugar in water. Such a mixture has two or more components.(ii) Heterogeneous mixture: In such a mixture the particles of each component of the mixture remain separate and can be observed as individual grains under a microscope, e.g. mixture of grains and sand.This type of mixtures contain physically distinct parts and have a non-uniform composition.Do You KnowMost homogeneous mixture are also known as solutions and examples of these include air, coffees, and even metal alloys.
Different Kind Of Mixtures With Examples
Soil is a mixture of clay & sand
Tiny particles of clay suspended in water
Milk is a mixture of tiny droplets of fatty oil in water
When you press the knob of an aerosol can, a mist of liquid droplets in a gas are seen
Requirement of Separation of a MixturesIn everyday more...
Learning Objectives1. To learn about materials that are used for making objects2. To understand grouping and sorting of materials3. To learn about classification and its importance4. To understand different properties of materials such as appearance .roughness .hardness, solubility, transparency, flotation, magnetic and conduction propertyWe have a number of objects around us like trees, toys, paper, table, chair etc.Some of these objects are living and some are non-living. Non-living objects can be man-made or natural. Objects around us may have different size, shapes, colours and uses. All objects around us are made up of one or more type of materials such as paper, glass, plastic, cloth, wood, metal, mud, soil, cotton, etc.An object can be made from different materials. For example, chair can be made from wood or plastic.Different objects can be made from the same material. For example window panes and fish bowl are made from same material, glass.Several objects are made up of combination of several materials. For example mango shake is made up of mango, milk, sugar etc.Different materials have different properties. Many objects differing in usage can be made from the same material. There are so many ways to group objects.Placing similar things together is called grouping-For example in supermarket grouping is done by keeping similar items on same shelf, which make it easier for us to find the item we need.CLASSIFICATIONThe process of sorting and grouping objects/things according to some basis is called Classification. It makes study of large number of objects of different type easier, simple, systematic and convenient.PROPERTIES OF MATERIALSDifferent types of materials have different properties. Some of the important properties of materials are given as following.AppearanceIn appearance materials usually look very different from each other. The appearance of wood is different from iron. Similarly appearance of iron is different from copper or aluminum.Some materials when freshly cut appear shiny where as others have no shine Metals shine in their pure state. This shining property of metal is called metallicIustre.Some materials having lustre are iron, copper, aluminum, gold, silver, etc.Materials can be classified on the basis of their luster as lustrous materials, for example gold, silver etc and non-lustrous materials for example wood, plastic, stone etc.Shining property of gold, copper and silver is used for making jewelry. Some metals often loose their shine when exposed to air and moisture for some time.HardnessHardness: On the basis of hardness more...
Learning Objectives1. To study different types of clothing materials2. To understand the concept of fibers, fabric and yam3. To know different sources to get fibers4. To study different plants, animal and synthetic fibers5. To understand different methods to get fabric from yam6. To know history of clothingWe wear clothes to protect our body against heat, cold, rain, dust and insects. At the same time we wear clothes to look good. That is why many of us want towear clothes that are in fashion.People in different regions of the world weardifferent kinds of clothes the kind of clothes people wear mainly depends onthe climate of the place. The traditional clothes worn by people in our countryvary considerably from region to region.. People living in hot countries wear light clothing. During summer we should wear loose fitting clothes to keep our body cool.People living in cold countries wear woolen clothes like -coats, jerseys, socks, caps etc. Dark coloured clothes are worn in winters because they absorb heat and warm quickly. FABRICSFabrics are materials made from weaving, knitting, spinning fibres together.Often the fibres are spun or wound together to form a thread before beingmade into a fabric. The nature of a fabric will depend on the fibres from which it is made and the way that they are arranged, and its properties will determine the applications for which it is suitable. Cotton, wool, silk etc. are examples of fabrics.YARNIt is made up of fibres. Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, knitting, weaving, embroidery, and rope making. Thread is a type of yarn.FIBRESA fibre a is thread which is strong and flexible enough to make clothes.Fibres can be broadly classified as natural fibres and synthetic fibres e.g.Natural fibres: Cotton, Wool, Silk, Pure jute etc.Synthetic fibres: Nylon, Polyester, Acrylic etc.Sources of Natural FibresNatural fibres are obtained from(i) Plant sources: cotton, jute.(i) Animal sources: wool, silkPLANT FIBRESCotton, sisal, flax jute, ramie, coir and hemp are examples of plant fibres.Theyhave more extensive use than animal fibresCottonCotton is a soft fibre that is obtained from cotton plant. Cotton is generally grown in such places that have black soil and warm climate. The fruits ofcotton plant are called cotton bolls. They more...