ngss chemistry webinar

Click here to load reader

Post on 06-May-2015

2.362 views

Category:

Education

0 download

Embed Size (px)

DESCRIPTION

An introduction and overview of the NGSS, with a particular emphasis on the science and engineering practices in chemistry.

TRANSCRIPT

  • 1.NGSS Models and Modeling in the Chemistry Classroom Larry Dukerich Dobson H.S. Mesa, AZ CRESMET Arizona State UniversityBrenda Royce University H.S. Fresno, CA Gary Abud, Jr. Grosse Pointe North H.S. Grosse Pointe, MI

2. The Problem with Traditional Instruction Presumes two kinds of knowledge: Facts and ideas - things packaged into words and distributed to students. Know-how - skills packaged as rules or procedures. Assumes students will see the underlying structure in the content. 3. Teaching by Telling is Ineffective Students Systematically miss the point of what we tell them. do not have the same schema associated with key ideas/words that we have. do not improve their problem-solving skills by watching the teacher solve problems 4. Algorithms vs Understanding What does it mean when students can solve stoichiometry problems, but cannot answer the following? Nitrogen gas and hydrogen gas react to form ammonia gas by the reaction N2 + 3 H2 2 NH3The box at right shows a mixture of nitrogen and hydrogen molecules before the reaction begins.=H =NWhich of the boxes below correctly shows what the reaction mixture would look like after the reaction was complete?ABCD 5. How Do You Know? All students know the formula for water is H2O. Very few are able to cite any evidence for why we believe this to be the case. 6. Do They Really Have an Atomic View of Matter? Before we investigate the inner workings of the atom, lets first make sure they really believe in atoms. Students can state the Law of Conservation of Mass, but then will claim that mass is lost in some reactions. When asked to represent matter at submicroscopic level, many sketch matter using a continuous model. 7. Representation of Matter Question: Whats happening at the simplest level of matter? 8. More Storyboards Gas Diffusion: Where s The Air?Aqueous Diffusion: The Continuous Model of Matter 9. Wheres the Evidence? Why teach a model of the inner workings of the atom without examining any of the evidence? Students know the atom has a nucleus surrounded by electrons, but cannot use this model to account for electrical interactions. Whats gained by telling a Cliffs Notes version of the story of how our current model of the atom evolved? 10. Instructional Objectives Construct and use scientific models to describe, to explain, to predict and to control physical phenomena. Model physical objects and processes using diagrammatic, graphical and algebraic representations. Recognize a small set of particle models as the content core of chemistry. Evaluate scientific models through comparison with empirical data. View modeling as the procedural core of scientific knowledge 11. What Do We Mean by Model?Models are representations of structure in a physical system or process 12. Why Models? Models are basic units of knowledge A few basic models are used again and again with only minor modifications. Models help students connect Macroscopic observations Microscopic representations Symbolic representations 13. Why modeling?! To help students see science as a way of viewing the world rather than as a collection of facts. To make the coherence of scientific knowledge more evident to students by making it more explicit. Models and Systems are explicitly recognized as major unifying ideas for all the sciences by the AAAS Project 2061 for the reform of US science education. 14. Uncovering Chemistry Examine matter from outside-in instead of from inside-out Observable Phenomena Model Students learn to trust scientific thinking, not just teacher/textbook authority Organize content around a meaningful Story of Matter 15. Particle Models of Gradually Increasing Complexity Begin with phenomena that can be accounted for by simple BBs Conservation of mass Behavior of gases - KMT Recognize that particles DO attract one another Sticky BBs account for behavior of condensed phases 16. Models Evolve as Need Arises Develop model of atom that can acquire charge after you examine behavior of charged objects Atom with + core and mobile electrons should explain Conductivity of solutions Properties of ionic solids 17. Energy - Early and Often Make energy an integral part of the story line Help students develop a coherent picture of the role of energy in changes in matter Energy storage modes within system Transfer mechanisms between system and surroundings 18. Reconnect Eth and Ech Particles in system exchange Ek for Ech to rearrange atoms 181 kJ + N2 + O2 > 2 NO Representation consistent with fact that an endothermic reaction absorbs energy, yet the system cools 19. How to Teach it? constructivistvstransmissionistcooperative inquiryvslecture/demonstrationstudent-centeredvsteacher-centeredactive engagementvspassive receptionstudent activity vsteacher demonstrationstudent articulationvsteacher presentationlab-basedvstextbook-based 20. Be the Guide on the Side Dont be the dispenser of knowledge Help students develop tools to explain behavior of matter in a coherent way Let the students do the talking Ask, How do you know that? Require particle diagrams when applicable 21. Preparing the Whiteboard 22. Making Presentation 23. NGSS Practices 24. Practice 1: Asking Questions and Defining Problems What Teachers Do?What Students Do?24 25. Practice 2: Developing and Using Models What Teachers Do?What Students Do?25 26. Practice 3: Planning and Carrying Out Investigations What Teachers Do?What Students Do?26 27. Practice 4: Analyzing and Interpreting Data What Teachers Do?What Students Do?27 28. Practice 5: Using Mathematics and Computational Thinking What Teachers Do?What Students Do?28 29. Practice 6: Constructing Explanations & Designing Solutions What Teachers Do?What Students Do?29 30. Practice 7: Engaging in Argument from Evidence What Teachers Do?What Students Do?30 31. Practice 8: Obtaining, Evaluating, and Communicating Information What Teachers Do?What Students Do?31 32. What Could It Look Like??? Lower EleUpper EleMiddle LevelHigh SchoolPractice 1 Practice 2 Practice 3 Practice 4 Practice 5 Practice 6 Practice 7 Practice 832 33. Practices of the NGSS I noticedI wonder33 34. How Important Is Energy? Topics/Content Skills34 35. A Coherent Approach to Energy Presentation at the Summer 2003 AAPT MeetingLarry Dukerich Dobson HS/Arizona State UGregg Swackhamer Glenbrook North HS, Northbrook, IL 36. Current State of Energy Concept Energy is regarded as an abstract quantity, invented for doing calculations Treatment of energy is inconsistent from discipline to discipline Students cannot use energy to adequately describe or explain everyday phenomena Students are taught that energy comes in different forms 37. The Problem with Transforming Energy Focus on changing one form of energy into another1 implies that there are different kinds of energy Forms of energy locution implies that somehow energy is changing - diverting attention from the changes in matter that we can describe James Clerk Maxwell argued against forms of energy treatment, calling it the old theory1- American Association for the Advancement of Science, Project 2061 Benchmarks Online, 38. Substance Metaphor Substance metaphor focuses attention on energy storage and transfer Energy is stored in different systems and in different ways in those systems, and it is transferred by some mechanism or other from one system to another2 Consider information It would be nonsense to say that hard disk information is transformed into wire information and then into RAM information and then into CD information3 Use of substance metaphor can integrate the way physics and chemistry approach energy 2, 3 - G Swackhamer, Understanding Energy-Insights 39. Problems with Energy in Chemistry Heat regarded as an entity, rather than a mechanism for energy transfer Different variables used interchangeably Q - what you can calculate E - what youd really like to discuss H - what you can discuss Only in college texts is treatment of 1st law of Thermodynamics more thorough 40. Problems with Energy in Chemistry Tenuous connection between kinetic energy and potential energy - typical examples are from realm of physics Students try to apply energy conservation to heating or cooling curves Kinetic energy changes with temperature Potential energy changes on plateaus Therefore, energy is shuttling back and forth between kinetic and potential 41. Problems with Energy in Chemistry Role of energy in bonding is muddled Rearranging atoms in molecules results in energy change But is it kinetic, potential or both? Students conclude that somehow bonds store energy ATPADP releases energy because high-energy phosphate bond is broken View is inconsistent with bond dissociation energy 42. Applying the Substance Metaphor Do brief coherent treatment of 1st Law of Thermodynamics - Modeling Instruction in HS Physics E n e r g y F lo w In itia l F in a l E kFTE gE eD ia g r a mE kE gEeE in tbox 00W Focus on ways to represent energy storage and transfer 43. Distinguish between attractions and chemical bonds Both involve electrostatic interactions Specificity and directionality of these interactions differ sufficiently that it is useful to treat them separately These interactions are associated with different kinds of change Attractions - physical changes Bonds - chemical changes 44. Two Categories of Potential Energy In physics, it is useful to subdivide potential energy into gravitational, elastic and electrical categories In chemistry, it is useful to consider two categories Interaction - due to van der Waals type attractions between particles (non-directional & non-specific) Chemical - due to bonds within molecules (covalent) or within crystal lattices (ionic). Bonds are directional and involve specific particles. 45. Attractions and Energy Attractions lower the potential energy of a system of particles, whether due to gravitational forces between macroscopic bodies e