5th Class

  Plants   Plants are very useful to us. Being a living thing, plants also reproduce to maintain the existence of their species. Plants reproduce in a number of ways: (i)      From their body parts (ii)     From spores (iii)    From seeds   Reproduction through Body Parts Some new plants grow from the parts of the mother plants. They grow from roots, stem and leaf. Such type of reproduction is known as vegetative propagation.   Root A sweet potato is a swollen root of the plant. The new plant of sweet potato can be grown from the roots of the original plant.   Stem Some plants can reproduce by burying a part of stem in the soil. From stem cutting, new shoots grow from buds. For example, Sugarcane, rose plant   Underground Stem Underground stems like potato and ginger have buds on them from where new shoots more...

  Animals   All animals breathe, feed and move. The place where an animal lives, eats, grows and reproduces is called its habitat.   Breathing All animals need to breathe for their survival. An animal breathes in oxygen and breathes out carbon dioxide, an exchange of gases takes place.   Fish A fish lives in water. The water passes out through a pair of gill-slits on each side of its body. As this water passes over the gills, the fish takes in oxygen and releases carbon dioxide, which flows out with the water. The oxygen gets absorbed into the blood of the fish.   Whale A whale looks like a fish and lives in water; but it is not a fish. A whale does not have gills. It has lungs. To breathe, it must come up to the surface of the water to fill its lungs more...

  Housing   Housing People at different places build different types of houses. There are some factors on which building of houses depends.    These are:

• The climate of the place
• Materials used for making houses
• The budget

  Climate In place where climate is hot, houses have thick walls and flat roofs. Thick walls keep the houses cool from inside. Flat roofs can be used by people for sleeping outdoors. In places where it rains a lot and climate is hot and damp, houses are built on stilts. These houses, built a few feet above the ground on raised platforms, remain safe from floods. The sloping roofs of houses on hills do not allow rainwater or snow to collect and make the houses damp and cold. Most houses in cold areas have fireplaces to keep their houses warm from inside.   more...

  Soil, Rocks and Minerals   Rocks The crust of the earth is made up of soil and rock. Rocks are made up of minerals. A rock can have one or many minerals. Rocks are found in the mountains, by seas, on the ground, and under it. Large rocks in the mountains are called boulders. Pebbles are small rocks. Sand is actually very tiny pieces of broken rocks. Depending on their formation, rocks are of three types: igneous, sedimentary and metamorphic.   Igneous Rocks The word igneous means made from fire or heat. Deep inside the earth in some areas it is so hot that even hard things like rocks melt. Molten rock is called magma. Sometimes the heavy rocks around the magma push it upwards towards the earth's crust. The magma comes out through a weak point on the surface of the earth. The place more...

  Work, Force, Energy and Simple Machines   Work Work refers to an activity that involves movement of the object when force is applied on it. For example, work is done when a person pushes a car and the car moves.       The formula of work is: \[~\mathbf{Work}=\mathbf{Force}\times \mathbf{distance}\] It means that more work is done, if more force is applied to an object, or the object moves larger distance, or both. If a force is applied on an object, but no motion takes place then no work is done. For example, if a person pushes against a wall, then no work is done unless the wall moves in the direction in which it is pushed. The unit of measurement of work is unit of force multiplied by the unit of distance i.e. Newton metre (Nm) or Joule (J). For example, if a stone is pushed more...

  Our Environment and Natural Calamities   Air and water form an essential part of our surroundings. Everything surrounds and affects an organism is known as its environment.   Air All living beings breathe in air. Air is needed for many purposes like lighting a fire, flying kites and inflating tyres. Air is a mixture of gases. More than three fourth of air contains nitrogen, slightly more than one fifth of air is oxygen and rest of the air contains gases like argon, carbon dioxide, ozone, helium, neon, etc. Air also contains dust/ smoke and water vapour.   Components of Air Components of air are as follows:   Nitrogen Nitrogen is the major component of air. Plants get nitrogen from the soil. Animals get nitrogen from plants, meat and fish.   Oxygen It is the most important gas present in air. It forms one fifth of more...

  Our Universe   The universe is vast. The solar system forms a very small part of the universe. Our earth is a one of the eight planets of the solar system. Yuri Gagarin was the first man to go into space Valentina Tereshkova was the first woman to go into space. Rakesh Sharma was the first Indian man and later Kalpana Chawla became the first Indian woman to go into space.   Solar System   Moon As the earth moves around the sun, it is accompanied by the moon. Even though the moor is earth's nearest neighbour in space, it is 3,84,400 km away from the earth. The moon is 4500 million years old, the same age as the earth. The moon is called the earth's natural satellite because it revolves around the earth. Why does the more...

  Light and Sound   Light Light is a form of energy which enables us to see an object. Sun is the main source of light on our earth.                                                                                                                                                                  Sun   Luminous Objects Sun, candle, diya and lamp are examples of objects that produce light. These are called luminous objects.                                                                                                                                                                                   Diya                                                                  Lamp   Non-luminous Objects The objects that do not produce light are called non-luminous objects. Paper, kite and table are examples of non-luminous objects.                                                                             more...

  Matter   Matter Matter is anything that occupies space and has weight. It is classified into three categories. Solid, liquid and gas. All matter can be split into tiny units that are not visible to the naked eye. These small units are called molecules.   Salt molecule is the smallest particle of salt.   Atom A molecule has smaller units called atoms. Atoms are building blocks of matter. There are 117 kinds of atoms known to us. Atoms of same kind form elements. Atoms of different kinds combine and form compounds.   Molecules are constantly in a state of motion and are attracted towards each other. In solids, molecules are tightly packed.   In liquids, molecules are less closely packed compared to solids. In liquid, molecules can move freely and can flow. That is why a liquid has definite volume but no definite shape. In more...

  Number Sense and Numerations   Numbers Numbers are mathematical symbol by which we express date, time, distance, position, quantity etc. We use ten symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) to write any number. Like 62232, 52155, 40034 etc.   Number System Number system deals with the study of different types of numbers. In this chapter, we will study about the categorization of different types of numbers.   Natural Numbers Counting starts with 1 and continue till infinite. Counting numbers are called natural numbers. For example, 1, 2, 3, 4, 5, 6, 7 ................ etc.   Whole Numbers When 0 is included with natural numbers, they are called whole number. In other words "Natural numbers together with zero are called whole numbers." For example, 0, 1, 2, 3, 4, 5, 6, 7 ................ etc.   Integers Integers are the collection of more...