Lesson TranscriptClass : IX Subject : Chemistry Unit : Nature of Materials Topic : Capillarity Curricular Statement The pupils understand about the concept of capillarity through observations and experimentations with the help of examples from daily life. Capillarity The upward movement of a liquid against the force of gravity inside narrow spaces and thin tubes is called “Capillary rise”. This property of the liquid is called Capillarity. However, liquids like Mercury which have high cohesive force shows “Capillary fall” inside such tubes. She asks them to dip one end of the cloth piece into the beaker and leave the other end to hang over the beaker. The entire cloth piece will get wet after some time.Activity: I A part of cloth dipped in water slowly gets wet fully. determinig which kind of straw has the strongest capillary action. Activity: II Capillary Action Experiment using different (narrow and wide) straws. . Teacher explains to the students about the action of capillarity. The teacher gives the students a piece of cloth and a bucket full of water. The students will test the capillarity of several different straws. She asks them to observe what happens. She asks them to dip one end of the straws into the beaker but don’t let them touch the bottom of the glass. Count for thirty. How the capillarity differs in different sized straws. wide and wider) and a glass filled with coloured water. The Teacher ends the class with review questions 1) What is Capillarity? 2) Differentiate between Capillary Rise and Capillary Fall? . Teacher explains how the plants use capillary action to grow on soil. Teacher explains to the students about the action of capillarity depends on the capillary tube.The teacher gives the students three different straws (narrow. The teacher familiarizes this plant with the students and dips the stem of the plant to some coloured water. Teacher tells the student to observe the capillary action through the translucent body of the plant. Mashithandu or Vettapocha is the household name of the plant Peperomia reflexa. She asks them to observe what happens. Activity: III Experiment to show how plants use capillary action to grow on soil by using a translucent plant. Strong attractive forces lead to high surface tension. . Surface Tension Surface tension is the elastic tendency of liquids which makes them acquire the least surface area possible. This property can be understood at the particulate level in terms of the strengths of the attractive forces among the particles that make up the liquid.Class : IX Subject : Chemistry Unit : Nature of Materials Topic : Surface Tension Curricular Statement The pupils understand about the concepts of surface tension through observations and experimentations with the help of examples from daily life. By naked eye. one cannot identify the shape of the liquid drop but this slow motion video (2500 frame per second) clearly shows the shape of the liquid drop which is spherical in shape.Activity: I Video to show how the liquid drops attain the smallest surface area when it is broken into small pieces. The teacher shows a video of falling of a small liquid drop. . The teacher mix oil with water in a closed container and shake it well such that the two liquids form a mixture. The teacher discusses about the surface tension of different liquids. The teacher explains the students about the properties of surface tension. Teacher tells the student to observe the container. Students will watch the video and discuss about it. After some time the two liquids will separate each other. Activity: II Experiment to show how two liquids separate each other when the liquids have different surface tensions. The Teacher ends the class with review questions 1) What is Surface Tension? 2) How liquid drops attain spherical shape? .Activity: III Video showing how different insects can walk on the surface of water. Teacher shows the students the video that how the lizards run through the surface of water and discusses about the properties of surface tension. Teacher introduce the students to the The common basilisk (Basiliscus basiliscus) is a lizard found in Central and South American rainforests near rivers and streams which is commonly known as the jesus christ lizard. Discuss the properties of surface tension with the students. Adhesion and cohesion are water properties that affect every water molecule on earth and also the interaction of water molecules with molecules of other substances. Adhesion and Cohesion Cohesion: Water is attracted to water. Activity: I Demonstration to show how soap can eliminate water's cohesive property .Class : IX Subject : Chemistry Unit : Nature of Materials Topic : Cohesion and Adhesion Curricular Statement The pupils understand about the concepts of adhesion and cohesion through observations and experimentations with the help of examples from daily life. Adhesion: Water is attracted to other substances. The teacher takes a shallow container with water. She drops a liquid soap in the center of the “V” shape at the rear of the boat. She cuts out a boat from an index card as shown in the figure. The Teacher explains the students about cohesive properties of water and how soap breaks the cohesion between molecules. She gently touches the pepper coated water with her finger. The teacher places the boat onto the water so that it is floating in the middle of the tray. The teacher tells the students to observe the effect of soap water on the pepper coated normal water. Activity: II Demonstration of cohesive forces in water and how these forces can be disrupted. The teacher dunk her finger into the soap solution and take some of the solution with her. one container with strong soap (dish wash) solution and in the other container with normal water. The teacher tells the students to observe and record what happens to the boat. The Teacher explains the students about cohesive properties of water and how soap breaks the cohesion between molecules. The teacher sprinkle small amount of pepper powder to the normal water so that it is evenly coated.The teacher takes two containers. . Activity: III Video showing 36 Drops of Water on a coin. The teacher shows a video which clearly depicts the adhesive and cohesive properties of water. The Teacher ends the class with review questions 1) What is Adhesion? 2) What is Cohesion? . In this video. The Teacher discuss to students about the cohesive and adhesive properties of water. it shows 36 drops of water adhere on a coin. Base indicators (also known as pH indicators) are substances which change colour with pH.Base indicators Acid . They are usually weak acids or bases. which when dissolved in water dissociate slightly and form ions. . Acid .Class : IX Subject : Chemistry Unit : Acids and Bases Topic : Acid Base Indicators Curricular Statement The pupils understand about acid base indicators through observations and experimentations with the help of examples from daily life. Activity: I Finding the solution whether it is acid or base using china rose stained paper. She tells the students to observe the colour change and report. Activity: II Shows the video how beetroot acts as Ph indicator . Again the students observe the colour change and report. She uses the given solution (Vinegar) and makes a spot on the stained paper. The teacher discuss with students about acids and bases and how china rose acted as an indicator. Then the teacher uses another solution (washing soda) and makes a spot on the paper. The teacher takes china roses with her and she stains it on drawing sheet. milk. The students observe and get a beautiful greeting card. The students will observe the colour change with each liquids and report. The Teacher ends the class with review questions 1) What is an acid-base indicator? 2) Discuss about pH scale? . Activity: III Makes a greeting Card using turmeric and soap solution The teacher applies turmeric paste on a sheet of plane white paper and dries it. The teacher draws a beautiful flower with soap solution with the help of a cotton bud. The teacher discuss with the students about pH value of different liquids.The teacher shows how beetroot acts as Ph indicator when it is used with different liquids such as vinegar. baking soda and bleach. Neutralization When solution of acid is mixed with the solution of base. both of them neutralize each other and a third substance. . Such phenomenon is called neutralization or neutralization reaction. called salt. is formed.Class : IX Subject : Chemistry Unit : Acids and Bases Topic : Neutralization Curricular Statement The pupils understand about Neutralization reaction through observations and experimentations with the help of examples from daily life. lemon and soap water The teacher takes three glass bowls. The teacher discusses about the neutralization reaction. Again the teacher drops lime juice drop by drop to the above solution till the color disappears to yellow. . Activity: II Tells about the neutralization reaction in everyday life. She tells the students to observe the color change. one with turmeric solution. other with soap solution and another with lemon juice. She drops two drops of turmeric solution into the soap water and the soap water changes the color to dark red.Activity: I Demonstration of neutralisation reaction using turmeric. The students observe the reactions.How ant sting is neutralized using moist baking soda. it injects the acidic liquid into the skin. Activity: III Animation on Neutralization reactions The teacher shows an animation in which the neutralization reaction is shown in details even to the molecular level. She describes how ant bites can be healed using neutralization reaction. which contains zinc carbonate. When an ant bites. The Teacher ends the class with review questions 1) What is Neutralization? 2) What is the end product formed after every neutralization reaction? . The teacher explains the importance of neutralization reaction in everyday life.The teacher tells the students about ant bites. The effect of the sting can be neutralised by rubbing moist baking soda (sodium hydrogen carbonate) or calamine solution.