Georgia Performance Standards Framework for Physical Science 8 th Grade

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1 The following instructional plan is part of a GaDOE collection of Unit Frameworks, Performance Tasks, examples of Student Work, and Teacher Commentary. Many more GaDOE approved instructional plans are available by using the Search Standards feature located on GeorgiaStandards.Org. Georgia Performance Standards Framework for Physical Science 8 th Grade Cheese Puff Lab Subject Area: Physical Science Grade: 8th Standards (Content and Characteristics): S8P2. Students will be familiar with the forms and transformations of energy. a. Explain energy transformation in terms of the Law of Conservation of Energy. c. Compare and contrast the different forms of energy and their characteristics. S8CS1. Students will explore the importance of curiosity, honesty, openness, and skepticism in science and will exhibit these traits in their own efforts to understand how the world works. a. Understand the importance of and keep honest, clear, and accurate records in science. b. Understand that hypotheses can be valuable even if they turn out not to be completely accurate. S8CS2. Students will use standard safety practices for all classroom laboratory and field investigations. a. Follow correct procedures for use of scientific apparatus. b. Demonstrate appropriate techniques in all laboratory situations. c. Follow correct protocol for identifying and reporting safety problems and violations. S8CS3. Students will have the computation and estimation skills necessary for analyzing data and following scientific explanations. a. Analyze scientific data by using, interpreting, and comparing numbers in several equivalent forms, such as integers, fractions, decimals, and percents. c. Apply the metric system to scientific investigations that include metric to metric conversions (i.e., centimeters to meters). d. Decide what degree of precision is adequate, and round off appropriately. e. Address the relationship between accuracy and precision. Use ratios and proportions, including constant rates, in appropriate problems. S8CS4. Students will use tools and instruments for observing, measuring, and manipulating equipment and materials in scientific activities utilizing safe laboratory procedures. b. Use appropriate tools and units for measuring objects and/or substances. c. Learn and use standard safety practices when conducting scientific investigations. August 13, 2008 Page 1 of 9

2 S8CS6. Students will communicate scientific ideas and activities clearly. a. Write clear, step-by-step instructions for conducting scientific investigations, operating a piece of equipment, or following a procedure. b. Write for scientific purposes incorporating information from a circle, bar, or line graph, data tables, diagrams, and symbols. c. Organize scientific information in appropriate tables, charts, and graphs, and identify relationships they reveal. S8CS9. Students will understand the features of the process of scientific inquiry. Students will apply the following to inquiry learning practices: a. Investigations are conducted for different reasons, which include exploring new phenomena, confirming previous results, testing how well a theory predicts, and comparing different theories. Scientific investigations usually involve collecting evidence, reasoning, devising hypotheses, and formulating explanations to make sense of collected evidence. Enduring Understanding: Energy is the ability to do work. Without energy, forces cannot be generated to make things move or change. Energy exists in two primary forms. Kinetic energy is the energy of motion. Potential energy is stored energy that has the potential to do work. Potential energy can be stored in foods. Foods release this energy when food is burned by our bodies. This energy can be used by our bodies to do work. Essential Questions: Why does matter undergo physical and chemical changes? How does the amount of matter compare before and after it undergoes a physical or chemical change? August 13, 2008 Page 2 of 9

3 ADMINISTRATION PROCEDURES Outcome / Performance Expectations: General Teacher Instructions: Materials Needed: Safety Precautions: Task with Student Directions: Resources: Homework / Extension: Instructional Task Accommodations for ELL Students: Instructional Task Accommodations for Students with Specific Disabilities: Students will observe that energy from one form of matter can be transferred through convection, conduction, and radiation. Students will be able to measure the amount of energy transferred. It is helpful if the teacher has the lab completely ready for student involvement. The skewers can be made ahead of time to reduce student confusion. Remind them that metals conduct heat very well and to not grab the skewer anywhere than by the insulated handle. Remind students that eating should never take place in the lab setting. Teachers may use the data tables at their discretion (some teachers may want to have students create their own). Small can paper clip wooden splint Ring stand duct tape thermometer water cheese puffs balance Review lab safety for flammables. Goggles should be worn and hair and loose clothing secured. The skewers are will become hot; make sure to insulate the handles with the duct tape. Students are not to eat in the lab. See the attached document at the end of the general task. See attached problem review sheet. Calories and Joules are used in the activity as units of energy. Students may use the formatted Excel spreadsheet to enter their measurements. The program will them calculate the heat absorbed by the water. Students may use the formatted Excel spreadsheet to enter their measurements. The program will them calculate the heat absorbed by the water. August 13, 2008 Page 3 of 9

4 CHEESE PUFF LAB Purpose: Rockets are powered by some type of fuel. All fuels convert chemical potential energy in to thermal energy. As gases are heated during combustion they expand and exert a force on their surroundings. This unbalanced force will cause acceleration and thereby changes the motion of the rocket. This force is commonly called thrust. The purpose of this lab is to calculate the amount of potential energy (Calories) in a cheese puff that may be used to heat surrounding gases. (ALTERNATE PURPOSE) Potential energy is stored energy. One very important source of this energy is the energy stored in chemical bonds. When the bonds are broken, the energy is released, and this energy can be used to do work. One way to break these bonds is through a process called combustion we often refer to this as burning. A car uses combustion to release the energy in chemical bonds of gasoline, and in the same way our cells use combustion to release the energy stored in the chemical bonds of our food. The purpose of this lab is to calculate the potential energy (Calories) in a cheese puff that can be used to heat surrounding gases. Q (heat) = m (mass) x C p x Δ T C p of water = 1 cal / gram o C Pre-lab Questions: 1. What is the Law of Conservation of Energy? 2. What is the difference between heat and temperature? 3. What is thermal energy? 4. Compare and Contrast conduction, convection, and radiation. August 13, 2008 Page 4 of 9

5 Useful information: One Stop Shop For Educators To determine the number of calories in food, small samples are placed in a calorimeter and burned. The increase in temperature of the surrounding water is measured and the calories are determined from the mass and the specific heat of the water. So, the heat lost by the cheese puffs is the heat gained by the water. Because the amount of calories in food is very large, food calories are actually kilocalories. Materials: Small Erlenmeyer flask (clean cans work well) paper clip wooden splint Ring stand duct tape thermometer Test tube clamp Cheese puff water balance Procedure: 1. Review lab safety for flammables. Goggles should be worn and hair and loose clothing secured. 2. Straighten the paper clip on one end. Wrap a small piece of duct tape on the opposite end for insulation. You now have a skewer. Mass the paper clip and duct tape. 3. Skewer the cheese puff length wise. Record the mass of the cheese puff and paper clip. 4. Measure the mass of the flask. Record 5. Add approximately 50 ml of water to the flask and record the mass. 6. Measure the temperature of the water. Record 7. Place the flask in the test tube clamp on the ring stand. 8. Light one end of the wooden splint, hold the paper clip by the insulated end and light the cheese puff. Immediately hold the burning cheese puff under the flask as close as possible without smothering the flame. 9. Once the cheese puff has extinguished itself, measure the final temperature of the water (stir the water slightly). Record. 10. Mass the skewer and cheese puff residue. August 13, 2008 Page 5 of 9

6 Calculations: One Stop Shop For Educators 1. Determine the mass of the water. 2. Determine the mass of the cheese puff consumed. 3. Determine the temperature change of the water. 4. Use your answers to numbers 1 and 3 to calculate the heat gained by the water Q (heat) = m (mass) x C p x T 5. The heat gained by the water is equal to the heat lost by the cheese puff. Calculate the heat lost by the cheese puff per gram of cheese puff. Heat lost per gram = Heat lost by the cheese puff Mass of the cheese puff Data Table 1 Mass of skewer + cheese puff Mass of skewer + residue Mass of cheese puff consumed Data Table 2 Mass of flask + water Mass of flask alone Mass of water Data Table 3 Final temperature of water Initial temperature of water Change in temperature August 13, 2008 Page 6 of 9

7 Conclusions: One Stop Shop For Educators 1. What instrument was used to measure the mass? 2. The cheese puff possessed chemical potential energy before the combustion reaction. As the combustion reaction proceeded, what type of energy was the chemical energy converted into? 3. How does your answer to #2 illustrate the Law of Conservation of Energy? 4. What types of heat transfer were observed during the reaction? Challenge Questions 5. Heat energy was lost by the cheese puff (transferred to water). Wait a minute! Does this mean that the Cheese puff gets cooler when you burn it? Why not? 6. How many calories does the manufacturer allow for each gram of Cheese puff? 7. How does the experimental value for calories compare to the actual value? What are some reasons for the differences? 8. Calculate the percent error for the calories of the Cheese puff. August 13, 2008 Page 7 of 9

8 Homework/Extension Name Date Heat Review C H20 = 1 cal/ g o C Heat = Mass of Sub. x Specific Heat of Sub. x Temp. Change Q = m c T 1. How many calories of heat area required to increase the temperature of 500 grams of water from 10.6 C to 50.6 C? 2. What temperature change will 100 grams of water undergo when it absorbs 200 calories? (Must rearrange equation to solve for T). 3. How many calories of heat area required to increase the temperature of 1000 grams of water from 10 C to 80 C? August 13, 2008 Page 8 of 9

9 4. What will be the final temperature if 50 ml of water at 20 o C absorbs 2,000 calories? 5. Calculate the energy (heat) lost when a.01 kg sample of aluminum (c = 920 J/kg K) cools from 75 o C to 25 o C. August 13, 2008 Page 9 of 9