Ray Optics and Optical Instruments
Lesson Plan for Class XII
Learning outcomes
? Students will understand the difference between virtual and real images.
? Students will extend their previous knowledge of reflection and refraction at plane surfaces to curved surfaces.
? They will further learn to apply these to understand how lenses form images.
? Students will learn about combination of lenses, and how they can be used to achieve desired results.
? Students will learn about the construction and working of some basic optical instruments: the compound microscope and the refracting telescope.
Key Ideas
? Types of images: real and virtual
? Image formation
? Magnification: lateral and angular
The Opening
Review the laws of reflection and refraction that the students are already familiar with. Discuss the two types of images, real and virtual, with attention to how they are formed. Also discuss ray tracing, another concept that they have learnt earlier.
Phase 1
Help them apply the laws of refraction and refraction to curved surfaces and derive the mathematical relations. Draw the figure on the board, and let them try to figure out the mathematical relations, with minimal guidance from the teacher. Pay special attention to rules of sign conventions, as they have not studied this before, and often tend to get confused.
Using these laws, ask them to derive mathematical expressions for lenses (lens formula and lens maker’s formula). They should be able to do this on their own, possibly with a little guidance.
Phase 2
Ask them to use a combination of ray tracing and mathematical manipulation to find out what happens when images are formed using a combination of two lenses.
Phase 3
Discuss how a convex lens can be used as a simple microscope. Take some time to discuss angular magnification, and comparing it with lateral magnification.
Discuss how a combination of two lenses can be used to construct a compound microscope and a telescope. Discuss both of these in detail, and in parallel, drawing out similarities and differences.
The Closure
Ask students to draw a table, listing the different kinds of images formed in different situations. This will help them review the chapter, organize their thoughts and will also act as self-assessment.
Activities
Give students as many kinds of lenses and mirrors, ask them to identify them as convex or concave, and find their approximate focal lengths.
Ask students to find out what kind of images are formed by different kinds of lenses and mirrors in different situations by practically forming images on screens.
The students can make a small microscope and telescope, using appropriate lenses. This will help them in understanding the difference between the two.
Assessment
Group discussions, along with individual numerical problem solving can be used to assess the students’ learning experience. Lively discussions on conceptual problems should be encouraged.
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Lesson Title: A Fun Way to Learn How Calories Leads to Weight Loss Equipment Needed: • “Joe’s Cutting Calories” PowerPoint Presentation (this is optional but you can get it for free at: http://www.teacherspayteachers.com/Product/A-Fun-Way-to-Learn-How-Cutting-Calories-Leads-to-Weight-Loss-Lesson • calculators • Joe’s Cutting Calories” worksheet (1 for each pair of students) I will cut and paste them here, but they will be in a better format at the above website for free! • food label sheets (1 for each pair of students) I will cut and paste them here, but they will be in a better format at the above website for free! • weight scale and height chart to check own height (I have just used a sharpie and put the height chart on the side on my bulletin board so I always have it Pre-Lesson To Do: • print worksheets-enough for 1 sheet for each pair of students • print food labels-enough for 1 sheet for each pair of students (I have these in protector sheets) Introduction: 1. I introduce my nutrition unit with the CDC’s obesity rates by state PowerPoint. Download it at: Think/Pair/Share: 2. “Why do you think Americans are becoming more and more overweight?” Students can turn and share with their table partner if you have time, and/or have a class discussion Lesson: 3. Go over the reasons too many Americans are overweight slides on PowerPoint. When you get to the portion sizes information, you can show the Portion Distortion Slide Show at: http://hp2010.nhlbihin.net/oei_ss/menu.htm#sl2 . I have some real magazine ads I show and discuss how the diet and weight loss ads are deceiving and unhealthy. (later in the PowerPoint I will show how it’s literally impossible for most people to lose “10 lbs. in 10 days” if they want to lose fat.) 4. Next I discuss the three main nutrients: Fat, Protein, and Carbohydrates. I cover that idea that the bottomline to weight loss or gain is calories in or out (and family genetics) 5. Ask students if anyone knows how many calories they should eat. Many will say “2000″ so I discuss how the food label says 2000 but that is an “average.” I tell them we are going to figure out EXACTLY how many calories they need, but first they must get their height and weight. Stress the importance of the correct weight; it’s needed for almost every formula in nutrition. 6. They get height and weight on own around your room. When everyone is done, talk about the weight range chart and that I don’t want anyone leaving depressed…rather be motivated. If they want to lose weight they should rather think of it as “eating healthy” and choose a plan they can do for LIFE. 7. Go through formula for calories with one student example on the board. After everyone is done I take the time to walk around and check each students (you’ll find several mistakes) Next I cover the healthy way to drop weight at 1-2 lbs. per week, the “set point theory” and “yo-yo” dieting.” 8. Show how it’s unhealthy and impossible to lose 10 pounds in 10 days like some ads claim. 9. Hand out “Joe’s Cutting Calories” worksheet (cut and pasted below…) and 1 set of food labels for each pair of students. (also see below) Go over the direction PowerPoint slides for “Joe’s Cutting Calories” worksheet (you may need to finish the worksheet tomorrow.) Point out that two of the labels have more than 1 serving per container and Joe is eating the whole thing so they’ll need to multiply the calories by how ever many servings there are. There are no right or wrong answers and they can drop 4 items or 1 item, it’s their choice. Think/Pair/Share: 10. Students will discuss with their partner how they want to have Joe drop 500 calories. When everyone is done I go around the room and have students share out. I question why they chose the foods they did and why Joe might have a hard time with their solution, or why it is a good idea, etc. 11. I conclude with the PowerPoint slides on how Joe could actually just have 1/2 a box of Mac n’ Cheese and he could do that for life…How it’s all about healthy choices you can sustain, and not about a fad diet . I also point out how Joe could double his weight loss with EXCERCISE. We’ll look more at exercise in a later lesson (*see lesson link below). Reflection: 12. If time, you have students reflect and set their own goals on eating healthy. This would be a good time to give my “Eating Healthy For Life” survey (*see link below). I also included a couple of slides to direct students to keep a food journal. You could use this to do the igoogle lesson in the future (*see below). 13. Homework could include filling out the goal sheet in the “Eating Healthy for Life” for a week (see link below) or you could take students to the computer lab and show them a cool calorie counter on igoogle and they could keep track of calories for a week. (*see lesson link below). Or, I also have a “Fat and Sugar Homework” assignment (*see link below). “Joe’s Cutting Calories” Worksheet: Names:_________________ + ______________________ Per:_______ 3500 calories = 1lb. Joe is a 16-year old teenager. He is 6’0 and weighs 250 lbs. Here is his typical food consumption for 1 day: Breakfast – 2 scrambled eggs, 2 pieces of bacon, 1 piece of toast, a glass of orange juice Snack – 1 Snickers candy bar Lunch – 2 pieces of pepperoni pizza, 2 bread sticks, and one cup of milk Snack- a box of Kraft Macaroni and Cheese Dinner – 1 Burrito, 1 cup of rice, a salad, and 1 20 oz. Coke Late night snack- 1 microwave popcorn bag Joe wants to lose weight in a healthy way and he has heard that if he drops 500 calories a day from what he usually eats, he will drop 3500 calories and that equals 1 lb. so he can lose 1 lb. a week. Obviously Joe’s daily food intake isn’t as low in fat as it could be and he is missing some important foods (like fruits and vegetables), and it would be smart for him to substitute some healthier foods, but for starters, let’s focus on the foods Joe could cut out or cut down on in his diet that would equal 500 calories, without changing any other eating habits right now. 1. Tell Joe what food(s) he could realistically cut out to equal 500 calories per day to lose 1 lb. per week. (there is no specific right answer since 500 calories can be cut in many different ways…) You can choose a whole food item to cut, and/or or have him lower the portion size of any item he’s eating. (you don’t have to choose 4!) Food(s):___________________________ Calories:_______________ Food(s):___________________________ Calories:_______________ Food(s):___________________________ Calories:_______________ Food(s):___________________________ Calories:_______________ Total Calories Cut: _________ 2. If Joe drops 1 lb. a week for 4 months, how much weight will he lose? 3. If Joe decides to start exercising on top of cutting those 500 calories, and he begins to walk to school and home everyday (and he’ll walk on the weekends too), he will burn another 500 calories per day. 4. How many lbs. can Joe lose in 4 months? (hint: now he is dropping 1,000 calories per day x 7 days per week and is losing 2 lbs. per week) **You can download the exact food labels from my free lesson on my website above which will help students learn to read food labels, (since they wouldn’t cut and paste here) but I have included the information on the labels so this lesson is complete as is: Microwave Popcorn Kraft Mac n’ Cheese Bacon Bread Sticks: Snickers Candy Bar Pepperoni Pizza Coke Egg Have Fun!! My website has other free and for sale lessons: https://sites.google.com/site/thebesthealthlessons or check out my full profile at: http://www.teacherspayteachers.com/Store/Mrs-Steele/Products You will find these other nutrition lessons for free and for sale: (just do a search for these titles) *A Fun Way to Learn How to Eat from All Food Groups Lesson: PwrPoint + *Lesson Plan: How Calories are Burned through Exercise Worksheet *Lose Weight, Get Healthier Plan: Individual Habits Survey + Check off *iGoogle Calorie Counter Worksheet: Learn How to Use Nutrition Gadgets *Fat and Sugar Experiment Lesson: Measure crisco + sugar into baggies! Nutrition Facts Food Label Reading Gaining Muscle Food Label Scavenger Calcium Lesson for How to Improve Body Why Water is Good Calorie Counting Health Lesson: Lesson Title: Food Label Reading Lesson and PowerPoint: Is this product healthy? Equipment Needed: http://www.teacherspayteachers.com/Product/Food-Label-Reading-Lesson-PwrPt-Is-This-Product-is-Healthy • calculators • Food Label Reading Worksheet -I will cut and paste below, but you can download it for free at: (http://www.teacherspayteachers.com/Product/Food-Label-Reading-Lesson-PwrPt-Is-This-Product-is-Healthy • 1 wrapper/product for each student or printed labels below-1 for each student. I will cut and paste below, but you can download it for free at: Pre-Lesson To Do: Introduction: 1. I hook students into this food label reading activity by talking about how companies may try to deceive you into buying their products and I show real products and have students get their calculators ready and help me add up some of these deceptions: (see 2nd PowerPoint Slide) • they may have an unrealistic serving size (I show them a real Tostitos bag where the serving size is 6 chips!) • servings per contanier may be unrealistic (show a real jumbo muffin wrapper that has 3 servings per container-how would you even cut that into thirds??!!) or show a King Size Chili Cheese Fritos with 4.5 servings per container (can you do that math in your head?) • it can have deceptive packaging (have a strawberry Poptart wrapper to show them-there are 4 strawberries on the front and then read them the ingredients) • beware of asterisks! (show a brownie box that lists the calories and fat of just the dry brownie mix-like who would just eat that?) or worse show them the most deceptive label I’ve ever found-Kraft Mac ‘n Cheese where it lists 2.5 grams of fat with an asterisk that tells you they’re just counting what’s in the box (in other words if you just ate the noodles hard out of the box!) With butter, milk and cheese it’s really 16 grams of fat and 3 servings per container so it’s really 48 grams of fat not 2.5!!!!) Think/Pair/Share: 2. If time you can have students turn to their partner and see if they can think of a product where the food label was deceptive. Share out to class if time. Lesson: 3. Go over the rest of the Food Label PowerPoint to teach how to read a fool label and what is most important on a food label. 4. Hand out the Food Label Reading worksheet to each student (they don’t choose a product yet) (I’ll cut and paste it below, but you can get it in a better format for free at the above website) 5. Next I go through the A & W sundae on the PowerPoint as they follow looking at their worksheet so they will know what to do when they choose a product. 6. After the explanation and demonstration, have each student either pick a product/wrapper, or have each pick a food label (free at the above link) to read. Walk around and help – it involves some math so have calculators handy and be ready to be a math teacher for a few minutes. Think/Pair/Share: 7. If time, you could go around the room and have each student share what % fat and sugar their product was and if it would make the vending machine. Reflection/Follow Up: Assessment/Homework: Homework could include students filling out the goal sheet in the “Eating Healthy for Life” for a week (see link below) or you could take students to the computer lab and show them a cool calorie counter on igoogle and they could keep track of calories for a week. (*see lesson link below). Or, I also have a “Fat and Sugar Homework” assignment (*see it at: http://www.teacherspayteachers.com/Product/Fat-and-Sugar-Homework-Visually-see-the-fat-or-sugar-in-products ). Food Label Reading Worksheet: Name:_______________________________________ Date:_________ Per:_______ copy a real food label here…………………. Choose a food label from the class box – the product must have fat and sugar in it: 1. Write the name of your food product here:_______________________________________ 2. Write the Serving Size of your product: _________________________________________ 3. How many Servings Per Container?___________________________________________ -If there is more than one serving per container, and you ate THE (Calories x how many servings = ) ______________. -If there is more than one serving and you ate the whole container, how many Total Fat grams would you really be eating? Is your product’s serving size realistic for you to eat? YES______ or NO______ Have they been deceptive by listing a small serving size? YES____ or NO______ 4. What is the Total Fat listing for 1 serving of your food?__________________ The two fats that are bad for you are: SATURATED FAT + TRANS FAT. If your product lists Saturated Fat, how many grams does it have in one serving?______ If your product lists the ingredients, do you see “hydrogenated,” or “partially hydrogenated” ? YES_______ (If yes, THAT’s TRANS FAT!) NO_______ 5. What is the Sugars listing for 1 serving of your food?__________________ TO BE CONSIDERED FOR OUR SCHOOL’S VENDING MACHINE AND A “HEALTHY” 6. FIGURE FOR FAT: Calories from Fat ÷ total calories =________________ % Total Fat Is your product’s total fat under 35%? YES_______ or NO_______ 7. FIGURE FOR SUGAR: Sugar grams x 4 (since there are 4 calories in every gram) ÷ total calories =________________% Sugar Is your products sugar less than 35%? YES_________ NO__________ IS YOUR PRODUCT HEALTHY ENOUGH TO BE IN THE SCHOOL VENDING MACHINE: YES _____________ NO______________ Have Fun!! My website has other free and for sale lessons: https://sites.google.com/site/thebesthealthlessons or check out my full profile at: http://www.teacherspayteachers.com/Store/Mrs-Steele/Products You will find these other nutrition lessons for free and for sale: (just do a search for these titles) *Food Label Scavenger Hunt Lesson: Worksheet + 42 Food Labels to Read *Lose Weight, Get Healthier Plan: Individual Habits Survey + Check off *iGoogle Calorie Counter Worksheet: Learn How to Use Nutrition Gadgets *Fat and Sugar Experiment Lesson: Measure crisco + sugar into baggies! *A Fun Way to Learn How Cutting Calories Leads to Weight Loss Lesson *A Fun Way to Learn How to Eat from All Food Groups Lesson: PwrPoint + *Lesson Plan: How Calories are Burned through Exercise Worksheet Nutrition Facts Gaining Muscle Calcium Lesson for How to Improve Body Why Water is Good Calorie Counting Health Lesson: Heartrate and Target |
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