Chemistry and Biology Lesson Plans and Concept Maps - Business Plan Example

TEACHER: Chemistry TIME: 60MIN LESSON HEADING/TOPIC: Describe the use of pH scale in comparing the concentrations of Acids and Alkalis LESSON OBJECTIVES: 1. Understanding the pH factor 2. Differentiating between acidic, basic and neutral substances 3. Carrying out experiments for identifying the properties of substances KEY CONCEPTS/IDEAS: 1. pH factor 2. Acid, base and neutral substances 3. Basic or alkaline substances SYLLABUS LINK: Prescribed Focus Area (PFA) Important of the pH factor in describing the chemical properties of substances and its impact on society and the environment Knowledge and Understanding In order to understand the chapter properly, the student/s require to have; 1. Understanding of the chemical composition of substances 2. Basic knowledge about carrying out experiments in a chemistry lab. 3. Ionisation of the compounds 4. Understanding of chemical basis of energy transformations in chemical reactions 5. Basic knowledge of chemical equations Skills 1. Ability to carry out experiments 2. Ability to justify the appropriateness of a particular investigation 3. Eye for observation around us with particular emphasis on accuracy and reliability. 4. Must be able to feel the difference in taste of acidic and basic (alkaline) substances Values and Attitudes 1. Ethical behaviour and desire for critical evaluation 2. Willingness to devote time for carrying out the experiments and observing the outcomes. 3. To take adequate precautions and not to indulge in undesired experiments in a chemistry lab, as it might lead to unpredictable and dangerous results. 4. Responsive towards the safety of all concerned. PLAN: TIME TEACHER ACTION STUDENT-CENTRED ACTIVITIES (including assessment of learning) RESOURCES OPENING (10-15 minutes) To start with, the teacher will come out with some practical aspects of the differences in acids and alkaline substances. This difference can be in the form of taste, odour, colour etc. which can be observed easily by an individual. Teacher talks about the pH factor (theoretical aspect) with main points like; Its discovery in 1909 by the Danish chemist Soren Sorensen. pH signifies ‘potential hydrogen’, that’s why we always talk in terms of hydrogen ions while differentiating between acids and bases. pH measures the degree of acidity In addition explain to the students that if pH factor is between 1 and 7 the substance shows acidic properties. If the pH factor is exactly 7 (e.g. distilled water), it is neutral. But when the pH factor is between 7 and 14 it shows alkaline properties. (This is based on the existing theoretical concepts) In addition some examples are provided to students which signify the difference between acids and bases. Some such examples are; i. Students are encouraged to come out with their observations/ examples, which in their opinion help in categorising acids and alkaline substances. For example: Some will find it interesting to talk about the difference tastes, some would speak about the composition of the substances etc. ii. Students are asked about the taste and experience when they consume certain types of food articles and how at times consumption of some food items might have resulted into bad taste or other after-effects like; Lemon Banana Water Milk Litmus paper Salt pH Meter (if available) Baking soda Vinegar Teaspoons Glass tumbler Beaker/ container Some phenolphthalein Ammonia Litmus paper colour scale (easily available) i. Acids are often sour or sharp to taste, while ‘bases’ are slippery and bitter. ii. Household vinegar contains acetic acid. Lemon juice, contain citric acid. iii. Bananas, mineral water, watermelon etc. are alkaline in nature In addition it also needs to be emphasized that there’s no fine dividing line between acidic and alkaline substances. There are some substances which can be acidic as well as alkaline in nature. Example: Orange can be acidic or alkaline depending upon the sourness or sweetness contained within. Similarly nutritionists often talk about acidic or alkaline forms depending upon their condition after ingestion. Some substances which are acidic in their natural form happen to be alkaline when broken down within our body. For example, vegetables with acidic properties show alkaline properties after being processed through the metabolic process, while foods from the animal world changes from alkaline to acidic. This happens because when this food is broken down, some of them will release H+, thus becoming acidic or accept H+, thus becoming alkaline. Pain in stomach Bad taste Nausea Teacher need to take precaution that stronger acids are not used during the experiments MAIN BODY Information about the pH values (35-40 Minutes) Chemical experiments Activity-1: Students are handed over pieces the litmus paper. Experiment-1 Take about half glass of water. Add some teaspoons of baking soda and mix the solution to make it concentrated Different students are then provided different types of acidic and basic liquids. And they are asked to dip the litmus paper into the solution. Add one spoon of vinegar to the solution Result: The colour of the litmus paper changes according to the pH value of the liquid. Students are then asked to write the approximate value of the pH factor by observing the colour of the litmus paper and matching it with the reading indicated on the colour scale. Result: A Chemical reaction takes place between baking soda (a basic substance) and vinegar (an acid substance). This results in formation of foam and bubbles. Activity-2: Experiment-2 Take a beaker Add some drops of phenolphthalein. Result- A colourless solution. Then, some drops of ammonia. The solution becomes reddish pink in colour. Phenolphthalein becomes reddish when the pH value of the solution exceeds 8.3. Ammonia increased the pH value of the solution. Add some drops of vinegar. The solution once again becomes colourless. This proves the Le Chateliers Principle. According to this principle, “If a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.” Place approx 20 ml of water in a beaker. Find out its pH value. Now place a straw in the beaker (Note: It will be better if we can cover the beaker by a piece of paper in such a manner that only the straw comes out of it) Ask some students (5-6) to gently exhale into the beaker for several breaths (1-2 minutes). This breathing implies mixing of CO2 in the water. Now once again measure the pH value of the water. There will be a difference in the pH value. To certain extent, this explains the phenomenon of acid rain. Such observation will help the students in applying the learning into practical experiment. CLOSURE (10-15 minutes) Learning Acidic and basic properties of substances The fact that a substance can display acidic or basic properties under different circumstances can be explained to the student by observing the experiment-2. Importance of the pH factor Different type of properties of a number of substances around us. EVALUATION After the lecture and experiments, the students will be able to have first-hand information about the nature of substances around us like fruits, vegetables, liquids, other eatables, chemical substances etc. The students will be able to differentiate between the substances on the basis of the pH factor Students will be able to carry out simple experiment with confidence Students will be able to spell out the properties of substances depending upon their acidic or basic nature. Concept Map TEACHER: CLASS: LESSON: STUDENT NUMBER: DATE: TIME: EQUIPMENT/CHEMICALS: Litmus paper Salt Vinegar Baking Soda Phenolphthalein Ammonia HINTS/ HAZARDS: Breathing in Ammonia vapours in excessive quantity can be harmful to health One must take adequate precautions while performing experiments in a chemistry lab Experiments must be conducted under strict supervision of teacher and some qualified laboratory assistants TEACHING AIDS: White-board Marker pens Instruction sets TEACHER: CLASS: Biology DATE: TIME: 60MIN LESSON HEADING/TOPIC: Osmosis and Diffusion LESSON OBJECTIVES: 1. Gaining first hand information about Osmosis and diffusion 2. How the processes of Osmosis and diffusion play an important role in our surroundings and lives. 3. Observing and learning about these processes - for carrying out experiments KEY CONCEPTS/IDEAS: 1. Cell membranes 2. Concentration of the liquids/ substances 3. Membrane permeability 4. Molecular movement 5. Facilitated diffusion 6. Osmosis 7. Diffusion 8. Tonicity of solutions: Hypotonic, Hypertonic and Isotonic SYLLABUS LINK: Prescribed Focus Area (PFA) Gaining an insight into the processes of Osmosis and Diffusion and how these processes are very common around us in a number of processes. Knowledge and Understanding In order to understand the concepts properly the students should have an understanding of; i. Cell membranes. Cell being the basic unit of life. ii. Capillary action – resulting in transport of liquid from one part to another iii. Some knowledge about the biochemical processes occurring in cells and macroscopic changes in organism iv. Some knowledge about the human evolution theory Skills i. Ability to carry out experiment ii. Patience in observing the experiments iii. Friendly with biological terminology iv. Ability to assess the validity of references and conclusions Values and Attitudes i. Ethical behaviour throughout the experiments ii. Positive attitude towards the task being carried out iii. Team spirit and respect for the time and devotion of all team members PLAN: TIME TEACHER ACTION STUDENT-CENTRED ACTIVITIES (including assessment of learning) RESOURCES OPENING (10-15 minutes) Teacher explains some practical examples of diffusion and osmosis like; i. The continuous use of oxygen by living cells during aerobic respiration. Oxygen molecules diffuse into cells thus increasing the oxygen concentration ii. Diffusion of oxygen from air to blood and carbon dioxide from blood to air. iii. The process of diffusion also enables metabolic wastes like CO2 to come out of the body. iv. How heating results in more movement of molecules and thus increasing the rate of diffusion. v. How our skin allows some liquids to pass through while others are stopped (depending upon the concentration of the liquid substances) vi. The process of dialysis in which blood transfusion takes place while retaining the larger blood cells and the proteins vii. Process of water filtering, which allows water to pass through but stops the larger molecules of dust particles. This fact can be better understood with the Reverse Osmosis (RO) process in water filters. Students are encouraged to come out with their own sets of observations and examples. In fact while telling the students about the examples of diffusion and osmosis; it will be a good idea to ask them about the difference between these two types of biological phenomenon. The students are bound to come out with their different sets of answers. Each such relevant answer may be recorded on the white-board (or black board), thus making the learning more interactive. Water Potato (membrane) Filter paper Ink pen Glass tumbler Beaker Perfume spray Salt Artificial membrane MAIN BODY To start with, we must explain the process of diffusion first, because Osmosis is a special case of diffusions. Students are to indulge in interactive session all through this lecture. (30-40 minutes) Definition of Diffusion: The net movement of molecular ions from an area of higher concentration to an area of lower concentration is termed as diffusion. Students are asked to observe the ‘movement’ and ‘feel’ the concentration of liquids of on both sides before and after the experiments. The molecules all always on the move from one region to other due to the inherent kinetic energy. This movement is also called thermal motion, which increases as the surrounding temperature become more. This movement happens to be random until provided a direction by some force. Diffusion therefore results in homogenous mixing. Students are also asked to have a look at the quantity of the liquids. Example: As cell is considered a basic unit of living beings, a number of fluids, particles etc. are to be sent across the cell membranes, in order to keep the cell alive. The processes helping in this task are diffusion and osmosis. Practical examples of Diffusion: Process of respiration by human beings Process of photosynthesis in plants In Kidney dialysis waste from the body/ blood is removed by diffusing across artificial membrane in the dialysis machine. This process doesn’t do any harm to blood cells and proteins. Experiment-1: Let us take a container vertically divided into two equal parts with the help of an artificial membrane (e.g. cellophane food wrap). This way we are able to have two chambers within one container. Now fill up Sodium Chloride (NaCl) solution on one side of the container (side-A) and pure water on the other side of the container (side-B). The solute concentration on both the sides of the container can be calculated beforehand. In this case, ideally, the solute concentration on the water side will be 0%, while on the other side normally we take the NaCl solution with 5-10% concentration. Slowly the solute starts diffusing from side-A to side-B, while water starts diffusing from side-B to side-A. Once again we measure the concentration on both the sides. We’ll find that now the concentration figures are different from the one’s in the beginning. Definition of Osmosis: It is the process of diffusion of water (or any such liquid) across a permeable membrane. The diffusion takes place from a high water potential to a low water potential. A dilute water solution has a higher water potential than a concentrated solution. In other words the solvent will tend to diffuse across the membrane from a less concentrated to the more concentrated solution. Some examples of Osmosis: Absorption of water by plant roots The kind of dehydration that we experience after drinking salty water (from sea, for example) is also a result of osmosis. In this case, when the salty water goes into our stomach, pure water starts coming out of our body due to osmotic pressure, which leads to dehydration and at times into death. In Reverse Osmosis fine filter is used to take out clear water from salty (or contaminated) water. In this case the salty (or contaminated water is put on one side of the permeable membrane and then pressure is applied to stop and subsequently to reverse the osmotic pressure. Experiment-2: We can divide a container as in above experiment in Part-A and Part-B with the help of a membrane. Let us put 100mM NaCl solution of 58 molecular weight (MW i.e. grams per mole) in part-A. And put 100mM glucose solution of 180 MW in part B. As a result water moves from part-B to part-A Similarly, we can put 10 gm insulin/litre (of 5800 MW concentration in Part-A, and 1 gm glycerine/ litre (of 75 MW) in part. Water would flow from part-A to part-B. Closure (10-15 minutes) Having told about a number of practical instances of diffusion and osmosis. The students are now asked to repeat some of the examples and the findings of the experiments. In addition, when the students try to be imaginative and goes into thinking process, a number of other examples might be there on the class board. This in turn helps in developing a regenerative thinking. Learning As a result of this lecture students are able to comprehend the difference between diffusion and osmosis. EVALUATION The lecture would be termed useful, if; The students are able to correlate the experiments with normal experiences in their life The students are able to conduct some such experiments on their own. Students are able to understand the process of reverse osmosis as well (which incidentally happens to be just the reverse of what happens in the process of osmosis) Concept Map Read More