Current Affairs 5th Class

         Soil Erosion   Removal of the top fertile layer of the soil due to weathering is called soil erosion. Heavy rain fall and wind are the cause of soil erosion.            Soil Erosion by Wind Particles from the top layer of the soil are lifted up by the Wind to carry it to some other place. This type of erosion of soil generally occurs in arid regions with little vegetation or no vegetation.                Soil Erosion by Rain and Running Water Due to cutting down of trees and less vegetation, the top fertile layer of the soil is exposed and hence it can be easily carried away with flowing water and rain water.              Soil Erosion by Overgrazing of Animals Overgrazing on the same piece of land without giving time for the growth of new plants erode the top fertile layer and make it barren or desert.                  Cutting Down of Trees Roots of trees hold the top fertile layer of the soil. Now a day in order to meet the demands of large scale industries and huge population, trees are being cut down at high rate. Deforestation exposes the top layer of the soil to the environmental factors such as wind, water, rain etc. Deforestation causes desertification                Deep Ploughing Deep ploughing throws the soil to one side and then to other side, when the tractor machine returns to the same part of land. This process loosen the top layer of the soil which can be easily carried by the agents like flowing water, rain, wind etc. Deep ploughing makes the soil very loose               How to Prevent Soil Erosion                Prevent Soil from Erosion by Afforestation We can reduce soil erosion by planting trees as the roots of the plants hold the top fertile layer of the soil firmly.            Prevent Soil from Erosion by Making Dam and Embankment Dam and embankment are the water storing and holding body. As result flow of water can be controlled, there by checking the soil erosion. Embankment reduces the speed of water waves              Preventing Soil Erosion by Terrace Farming more...

     Soil   Soil is the uppermost layer of the earth's surface which is made up of the particles of rocks, humus, air and water. Soil contains nutrients and water for the survival of plants. The product, after the process of photosynthesis is glucose, which is made by the plant in the presence of carbon dioxide and Sun rays. The leaves of the plant trap Sun rays and carbon dioxide from the atmosphere. The other necessary nutrients such as, water and minerals are absorbed by the root from the soil. Therefore, the growth of the plant depends on the quality of soil.              Formation of Soil Soil is formed from rocks by weathering. Rocks are broken down into small pieces due to heat of the Sun, wind, snow, rain and natural events like earthquakes to form soil. Soil formation as well as fossil fuel formation is a very slow process. It takes millions of years to form particles of soil from rocks. Roots of few plants can also break rocks by penetrating deep into the space of rocks. Weathering of rocks due to flowing water               Different Layers of Soil     Top soil or A-horizon is dark in colour and rich in minerals and humus. This layer is soft, porous and can retain water. Plants grow in this layer. This layer is beneficial for worms, beetles, rabbit, rats and moles as it provides shelter to these organisms. Sub soil or B horizon lies below the top soil. It is grey or red in color. It is comparatively harder and made up of hard broken pieces of rocks. A type of rock which is called Bed rock is found below the surface of the earth. Bed rock consists of hard non porous rocks.                   Components of Soil                                                                                                                                                                 Pot made from                 Crops grown in loamy            Sandy soil is used                Clayey soil                            loamy soil                         as building material     Residual soil: Soil more...

         Separation of mixture                   Interconnection of the different states of the matter SOLID                        LIQUID                      GAS                                                                                     Releasing heat                                   releasing (heat)              Melting (heat)                               vaporization (heat)         The above mentioned examples are physical change that can be brought back either by giving or loosing heat- Physical change is reversible. Burning of paper is a chemical change as ash can't be brought back to paper by any means. Chemical change is irreversible.                             Rusting of Iron                                     Burning Paper     Growth from an infant to an adult is an irreversible change.                 Which of the following plays an important role In the process of changing one state of matter into another? (a) Heat (b) Volume (c) Mass (d) Density (e) None of these   Answer: (a) Explanation One state of matter is converted into another form either by taking or releasing heat energy. Therefore, option (a) is correct and rest of the options is incorrect.           Which one of the following is an example of liquid state of matter? (a) Air (b) Soil (c) Water (d) All of these                                  (e) None of these   Answer; (c) Explanation Water is an example of liquid stale of matter. Therefore, option (c) is correct and rest of the options is incorrect.

       Introduction   Everything, which we see around us is called the matter. Matter is made up of atoms and atoms are made up of electrons, protons, and neutrons. There are three states of matter, solid, liquid and gas. The properties of solid, liquid and gas states of a same matter are different. The atoms in the solid are tightly packed in comparison to the structure of atoms in liquid and gas. In this chapter, we will study about the properties of different types of matter.          Matter Anything which occupies space and has mass is called matter. Amount of matter present in a body is called the mass of the body. Mass of a body is constant and remains same, even in the space. Volume is the amount of space, which is occupied by the body or an object. Amount of occupied space by an object is called its volume. The whole universe is made up of only two things, matter and energy.                     Properties of Three States of Matter more...

Catgeory: 5th Class

Data Handing

LEARNING OBUJECTIVE This lesson-will help you to:—  

• Understand how to group data.
• Draw frequency distribution table.
• Learn how to make bar graph.

  Historical preview

• Statistics is the collection, organization analysis and interpretation of data it can be assumed to have started around 1749. There have been many changes since then in the beginning it was just about collecting the data about states but later stared to information of all types.

  QUICK CONCEPT REVIEW There are so many things and works in our lives. We all manage and collect the details of the work we do. Every office keeps the records. We need to collect the information and there is even more need to arrange' that information. We need to do grouping of the data collected. We cannot keep the information ungrouped as it will be very difficult to retrieve any information at the time of need... We shall learn about some of the ways to group or to handle the data. (1) Making the table: The first step to group any data is to make a table category wise. For example: Rajesh threw a dice twenty times. The outcomes were: 5,344,5,6,3,2,4,4,5,5,5,2,1,6,5,3,6,6 If we want to see which number appeared how many times it becomes a bit difficult to count each number? So we can group them as follows: First of all we see how many numbers are there which are appearing. As we know there are 6 faces of the dice so there will be numbersl.2, 3,4,5,6 which will be appearing. Each time the number appears we put a mark | in front of that number. So I means 1, || means 2, ||| means 3, III means 4 and we represent 5 as \[\bcancel{||||}\] so 6 will be \[\bcancel{||||}|\] and so on. These symbols are called tally marks.   Some Terms

• The data which is given in the beginning (like data in the example above) is called ungrouped or raw data.
• Each entry in the list is called observation.

  So the table will be as follows; (This table is called frequency distribution table.)  

Properties	Solid	Liquid	Gas
Mass	It has mass	It has mass	It has mass
Occupy space	It occupies space	It occupies space	It occupies space

more...

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Number on the dice	Tally marks	Frequency
1	|||	3
2	||	2