UC Irvine FOCUS! 5 E Lesson Plan Title: Hot! Hot! Hot! Grade Level and Course: Grade 7 Life Science Grade 8 Physical Science Grade 9 Chemistry Grade 9 Physics Grade 10 Biology Materials: HotSnapZ hand warmer Styrofoam cups Thermometer Balance Stopwatch water Instructional Resources Used: (concept maps, websites, think-pair-share, video clips, random selection of students etc.) Mixed levels groups of four, each student has a job: scribe who records data, lab technician who reads temperature, leader who makes sure all parts of lab are followed correctly, assistant who gathers materials and equipment. Hands on, inquiry based investigation California State Standards: Grade 7 Investigation and Experimentation 9. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, student should develop their own questions and perform investigations. Students will: o Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data. Grade 8 Physical Science: 3.d. Students know the states of matter (solid, liquid, gas) depend on molecular motion. 3.e. Students know that in solds the atoms are closely locked in position and can only vibrate, in liquids the atos and molecules are more loosely connected and can collide with and ove past one another, and in gases the atoms and molecules are free to move independently, colliding frequently. 5.c. Students know chemical reactions usually liverate heat or absorb heat. 5.d. Students know physical processes include freezing and boiling, in which a material changes form with no chemical reaction.
Grade 9 Physics Heat and Thermodynamics: 3.a. Students know heat flow and work are two forms of energy transfer between systems. 3.b. Students know that the work done by a heat engine that is working in a cycle is the difference between the heat flow into the engine at high temperature and the heat flow out at a lower temperature (first law of thermodynamics) and that this is an example of the law of conservation of energy. 3.c. Students know the internal energy of an object includes the energy of random motion of the object s atoms and molecules, often referred to as thermal energy. The greater the temperature of the object, the greater the energy of motion of the atoms and molecules that make up the object. 3.d. Student know that most processes tend to decrease the order of a system over time and that energy levels are eventually distributed uniformly. Grade 9 Chemistry Chemical Thermodynamics: 7. a. Students know how to describe temperature and heat flow in terms of the motion of molecules (or atoms). 7.b. Students know chemical processes can either release (exothermic) or absorb (endothermic) thermal energy. 7.c. Students know energy is released when a material condenses or freezes and is absorbed when a material evaporates or melts. 7.d. Students know how to solve problems involving heat flow and temperature changes, using known values of specific heat and latent heat of phase change. Common Core State Standards: Grade 7 Writing: 10. Write routinely over extended time frames (time for research, reflections, and revision) and shorter time frames (a single sitting or a day or two) for a range of discipline-specific tasks, purposes and audiences. Grade 7 Speaking and Listening: 4. Present claims and findings (e.g., argument, narrative, summary presentations), emphasizing salient points ins a focused, coherent manner with pertinent descriptions, facts, details and examples; use appropriate eye contact, adequate volume and clear pronunciation. Grade 9-10 Writing: Write routinely over extended time frames (time for research, reflections and revision) and shorter time frames (a single sitting or a day or two) for a range of asks, purposes and audiences. Grade 9-10 Speaking and Listening: 4. Present information, findings, and supporting evidence clearly, concisely, an logically (using appropriate eye contact, adequate volume and clear pronunciation) such that listeners can follow the line of reasoning and the organization, development, substance and style are appropriate to purpose (e.g., argument, narrative, informative, response to literature presentations),
audience and task. Lesson Objectives: To evaluate the energy content of a commercial hand warmer using calorimetry. Differentiation Strategies to meet the needs of diverse learners: English Learners: Students will list unfamiliar words in relation to this lab. Each will ask the group to define or explain it, e.g., calorimetry is to measure a unit of heat. Special Education: Students will be incorporated in appropriate groups that will allow them to successfully complete the task. GATE: Students will develop another experiment using the hand warmers that demonstrates the energy content, e.g., How much longer will it take for the hand warmer to no longer produce heat? or research the chemical makeup of the substance inside the hand warmer. ENGAGE Describe how the teacher will capture the students interest. o As a continuation of the unit Think Like a Scientist which focuses on the Scientific Method, students will be told the day before that there will be an investigation the next day. All tools and materials for the investigation will be out on each table. The teacher will ask, What do you think we will doing with these items? Students will give suggestions at table group and then one person from each group will be asked to share to the whole class. o What questions will the teacher ask during the engage piece? 1. So far in this unit on the Scientific Method we have discussed and done hands on activities with observation skills and stating hypotheses. Today we will be using tools to measure temperature changes of water using commercial hand warmers, a triple beam balance, beakers, thermometer and water. What do you think we will do first to set up this experiment? (measure the present water temperature, activate the hand warmer) 2. What do you predict will happen to the water temperature as time passes? (It will drop slowly and level off) 3. Will each group s results be the same? Why or why not? EXPLORE: Describe the hands-on laboratory activity that the students will be doing. o Students will record temperature changes in water as the hand warmer releases energy in the form of heat over a period of ten minutes. They will then plot a graph of temperature (T) vs t (time) as T is recorded. List the big idea conceptual questions that the teacher will ask to focus the student exploration. 1. What good lab practices were important for this investigation? 2. What happened to the heat as time passed? 3. Why did we measure the mass of the water? 4. How did we measure the temperature? 5. What does our graph communicate? EXPLAIN What is the big idea concept that students should have internalized from doing the exploration?
Middle school explanations: Many chemical reactions release energy in the form of heat, light, or sound. These are exothermic reactions. Other chemical reactions must absorb heat in order to proceed. These are endothermic reactions and work must be done in order to get these reactions to occur. In this exploration, heat was released by the hand warmer and was transferred to the water. Thus an exothermic reaction occurred. As time passed the water temperature rose, eventually plateaued and decreased. High School explanation: o Many chemical reactions release energy in the form of heat, light or sound. These are exothermic reactions. Exothermic reactions may occur spontaneously and result in higher randomness or entropy (delta S > 0) of the system. They are denoted by a negative the flow (heat is lot to the surroundings) and decrease in enthalpy (delta H < 0). In the lab, exothermic reactions produce or may even be explosive. There are other chemical reactions that must absorb energy in order to proceed. These are endothermic reactions. Endothermic reactions cannot occur spontaneously. Work must be done in order to get these reactions to occur. When endothermic reactions absorb energy, a temperature drop is measured during the reaction. Endothermic reactions are characterized by positive heat flow (into the reaction) and an increase in enthalpy (+delta H). Source: http://chemistry.about.com/cs/generalchemistry/a/aa051903a.hrm EXTEND List the higher order questions that the teacher will ask to solicit student explanations for their laboratory outcomes, and justify their explanations. 1. Does T increase or decrease with time? 2. Is this endothermic or exothermic? Explain. 3. What other observation(s) can you describe? 4. Identify and explain possible sources of error. (Hint: think about where energy also might have gone). 5. The manufacturer states this process is reversible. What does this mean? 6. How might this happen? Explain how students will develop a more sophisticated understanding of the concept. Grade 7 explanation: o As stated above, this investigation is a part of a series on observation, asking questions gathering data, making hypotheses, recording data, and communicating results. How is this knowledge applied in our daily lives? o Student groups will list as many heat transfer examples as they can, e.g., hot pan on stove can transfer heat to the counter top, heat from the window can transfer heat into the room. Background Knowledge for the Teacher:
Middle School: o The scientific method is a process for predicting, on the basis of a handful of scientific principles, what will happen next in a natural sequence of events. Because of its success, this invention of the human mind is used in many fields of study. The scientific method is a flexible, highly creative process built on three broad assumptions: o Change occurs in observable patterns that can be extended by logic to predict what will happen next. o Anyone can observe something and apply logic. o Scientific discoveries are replicable. o The scientific method ultimately allows for the formulation of scientific theories. Part of science education is to learn what these theories are and trace their operation in the world. A theory in popular language is a collection of related ideas that one supposes to be true; in science, a theory is defined by the principles of the scientific method. Those principles, in order of precedence, are as follows: 1. A scientific theory must be logically consistent and lead to testable predictions about the natural world. 2. The strength of a scientific theory lies solely in the accuracy of those predictions. 3. Of two scientific theories that make accurate predictions, the theory that makes a greater number of predictions with fewer underlying assumptions is likely to prove stronger. The making and testing of predictions is what distinguishes science from other intellectual disciplines, and emphasizing the accuracy of predictions rather than the cogency of explanations is the key to scientific progress. A large assortment of recorded observations can often be accounted for with explanations that sound good but are nonetheless wrong. Predictions that can be tested and verified, however, provide a sound standard by which a scientific theory can be judged. http://www.cde.ca.gov/ci/sc/cf/documents/scienceframework.pdf Student pages are attached.
Hot! Hot! Hot! An Energy Experiment Objective: calorimetry. To evaluate the energy content of a commercial hand warmer using Materials: HotSnapZ hand warmer styrofoam cup water thermometer balance stopwatch Procedure: 1. Mass the hand warmer. 2. Place in calorimeter (cup). 3. Add water to almost fill the cup, and then remove the hand warmer. 4. Measure the temperature of water in the cup (T0). 5. Trigger the hand warmer by clicking the button. 6. As quickly as possible: remove thermometer, place hand warmer back in cup, replace thermometer, record temperature as a function of time (t). 7. Plot a graph of temperature (T) vs. time (t). Data: Mass of hand warmer Time (t) Temperature (T)
Evaluate: 1. Does T increase or decrease with time? Is this endothermic or exothermic? Explain. 2. Is this a linear function? If not, describe the curve. 3. What other observation(s) can you describe? 4. What can you suggest is happening? 5. How might you investigate further?
6. Why did the temperature depend on time in the way it did? 7. Each calorie of heat causes 1 gram of water to increase its temperature by 1 o C. Can you calculate how many calories of heat your warmer finally transferred? 8. Express calories per gram of warmer. Compare to what other groups obtained (look at the class distribution) 9. Identify and explain possible sources of error in this number (Hint: think about where energy also might have gone). 10. The manufacturer says this process is reversible. What do they mean? How might this happen? Could you just go on getting more and more heat flow from this warmer? Does that violate the law of conservation of energy? Why or why not? Explain. 11. If resources exist, find explanations for what is going on inside the warmer in terms of molecules. 12. Is the change you see in the hand warmer a physical change or a chemical change? Explain.