Conservation of Matter: A Modeling Approach As you arrive, take the first handout. Please work on the Challenge Question.

Conservation of Matter: A Modeling Approach California Science Education Conference 2013 Rich Hedman--Sacramento AREA Science project (CSUS) Lysa Munson--Al Arqam Middle school, sacramento Kaye Schwartz--james rutter middle school, sacramento

Context The lessons you are going to experience were designed by three teachers and a facilitator engaged in the process of lesson study. The lessons were designed for middle school students, but are applicable to students at any grade level. All the handouts and instructions (including this PowerPoint) will be available for download from our website, so please write on the handouts we provide you. Funding for our work was provided through a California Mathematics and Science Partnership (CaMSP) grant called Excellence in Science Education Plus (eSCI+). The grant provides for collaboration between the Elk Grove Unified School District, Sacramento State, UC Davis, and the Sacramento Area Science Project.

Let’s begin by collecting some data…

Experiment #1 Turn to the Experiment #1. You will be given some materials. Follow the instructions. Record your results. You have 8 minutes.

Let’s review the particle model of matter… The particle model of matter was developed with our students earlier in the school year.

The Particle Model of Matter Everything in the world is made of extremely small particles. These particles are arranged and spaced in certain ways. The particles in a substance can have empty space between them. In a gas, there is a lot of empty space between the particles. In a solid, the particles are close together and locked in place. In a liquid, the particles are as close together as in a solid, except they can change position and move around each other. These particles move. All particles show some amount of motion. Temperature is an indicator of the amount of motion.

Models in Science Models are sets of ideas about how some feature of the natural world works. These sets of ideas (i.e. models) can be used to explain, predict, and make sense of phenomena.

These are NOT the kinds of models we are talking about: These are physical replicas or representations that may be useful in communicating about and reasoning with underlying models.

For More on Modeling: Join me tomorrow (Saturday) in this room from 9:30- 10:30am: Understanding Modeling, the NGSS Practices, and Day & Night

Apply Model to Construct Explanation of Your Experiment #1 Results Apply the particle model to construct an explanation as to why the mass stayed the same before and after mixing. On poster paper. You must include a drawing and a written response. Post on wall when complete. You have 8 minutes.

Apply Model to Construct Explanation of Your Experiment #1 Results What patterns can we see when we look across all the posters?

Let’s gather additional data…

Experiment #2 Turn to the Experiment #2. You will be given some materials. Follow the instructions. Record your results. You have < 5 minutes.

Discuss Experiment #2 Results What are your results? Why? What could have caused your results?

Let’s test your ideas…

Experiment #3 Obtain Experiment #3 handout. You will be given some materials. Follow the instructions. Record your results. You have < 5 minutes.

Apply Model to Construct Explanation of Your Experiment #3 Results Apply the particle model to construct an explanation as to why the mass stayed the same before and after mixing. On poster paper. You must include a drawing and a written response. Post on wall when complete. You have 8 minutes.

Experiment #3 = Chemical Reaction Experiment #3 was a chemical reaction. What is the evidence?

Generalizing from Specific Cases We can use the results of all three experiments, and our posters explaining what happened at the particle level, to create a general statement about matter. We had students work together in small groups to write a final concluding statement regarding what these experiments tell us about matter in general.

General Statement About Matter When substances are mixed (even if there is a chemical reaction), the total mass is the same before and after the mixing. This is because particles of matter are not created or destroyed when substances are mixed, even if there is a chemical reaction. The number of particles of each element are the same before and after the mixing, so the total mass of everything stays the same. This is a big idea of science: CONSERVATION OF MASS!

Which standard is this? current California standards and ngss

8th Grade CA Science Content Std. 5b. 5. Chemical reactions are processes in which atoms are rearranged into different combinations of molecules. As a basis for understanding this concept: b. Students know the idea of atoms explains the conservation of matter: In chemical reactions the number of atoms stays the same no matter how they are arranged, so their total mass stays the same.

NGSS Middle School Physical Sciences MS-PS1-5 Performance Expectation Students who demonstrate understanding can: Develop and use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved.

Discuss Our Original Experiment #3? Only if we have enough time left: Do the demonstration. Ask participants to explain the results. Discuss.

Questions? All files can be downloaded from: http://saspcsus.pbworks.com Rich Hedman: hedmanrd@csus.edu Lysa Munson: lysa@lhamous.com Kaye Schwartz: kschwart@egusd.net Conservation of Matter: A Modeling Approach CA Science Education Conference 2013