1. LIVE INTERACTIVE LEARNING @ YOUR DESKTOP May 24, 2012 ACS: Matter – Solids, Liquids, and Gases: Introducing a Free Online Resource for Middle School Chemistry Presented by: James Kessler

2. American Chemical Society Middleschoolchemistry.com Big Ideas about the Very Small Chapter 1: Matter – Solids, Liquids, and Gases

3. American Chemical Society Welcome Six chapters of activity-based lesson plans that align with state standards and national frameworks in physical science and inquiry. Two main goals: Help students understand and be able to explain basic chemistry concepts on the molecular level. Help students to design and conduct valid scientific experiments. What is middleschoolchemistry.com?

4. American Chemical Society What’s in a Chapter? Fully-developed 5-E Lesson Plans –Hands-on Activities –Student Activity Sheets –Multimedia –Extra Teacher Background Student Reading Test Bank

5. American Chemical Society Goals of the Webinar Demonstrate how the activities and animations from the lessons in Chapter 1 can be used with students Review basic chemistry concepts covered in the Chapter 1 lessons

6. Big Idea for Chapter 1: Have never thought about it and happy that way Willing to listen if it doesn’t take too long Stay up nights pondering this question Why are different substances solid, liquid, or gas at room temperature? Use the “Fascination Number Line” to input your level of fascination with this question. American Chemical Society

7. Lesson 1.1 Molecules Matter What are some examples of matter? EngageExploreExplainEvaluateExtend American Chemical Society

8. Attractions between Water Molecules EngageExploreExplainEvaluateExtend Students observe water on wax paper. Does the water drop stay together or come apart easily? If water was made of tiny particles (molecules), would you say they are attracted to each other or not?

9. American Chemical Society The Motion of Water Molecules ExploreEngageExplainEvaluateExtend What else can we learn about the particles that make up water? Why do you think the food coloring spread out? If the food coloring is also made of particles, how could the water molecules help to spread them out?

10. American Chemical Society Molecular Model Animation - Liquid ExploreEngageExplainEvaluateExtend Attractions keep molecules close together. Molecules are in motion and move past each other.

11. American Chemical Society Drawing a Model of a Liquid The student activity sheet serves as the “Evaluate” for each lesson. ExploreEngageExplainEvaluateExtend Students draw a model of water molecules and a caption to describe what their model represents.

12. American Chemical Society Effects of the Attractions of Water Molecules ExploreEngageExplainEvaluateExtend Why do you think the water keeps its shape the moment the balloon is popped?

13. American Chemical Society Play a Water Game Let’s play “Water Drops Unite” & “Race Drop Raceway” ExploreEngageExplainEvaluateExtend

14. American Chemical Society Why are Water Molecules Attracted to Each Other? The water molecule is composed of two hydrogen atoms bonded to an oxygen atom. These are covalent bonds in which electrons are shared between the oxygen atom and the hydrogen atoms.

15. Water Molecules are Polar American Chemical Society In the bonds in a water molecule, the electrons are not shared equally. The electrons are more attracted to the oxygen atom than to the hydrogen atoms. This makes water a “polar” molecule.

16. American Chemical Society Water Molecules Attract Each Other Water molecules attract one another according to their opposite polar ends. This accounts for the cohesion between water molecules and gives water many of its characteristic properties.

17. Let’s pause for questions from the audience

18. American Chemical Society Lesson 1.2 Heating and Cooling Water If you wanted to test whether heating or cooling water affects the motion of the molecules, how could you do it? How would we make sure our test is fair? Ask students: What do you think you could do to the water to make the water molecules move faster?

19. American Chemical Society Heating and Cooling Water On the molecular level, why does heating the water affect how fast the food coloring mixes in the water? Adding or removing energy affects the speed of molecules: Heating a liquid increases molecular motion Cooling a liquid decreases molecular motion

20. American Chemical Society Moving Molecules Aside from moving faster or slower, what else changes about water molecules as the temperature changes? Add energy: Further apart Faster motion competes with attractions Remove energy: Closer together Slower motion competes with attraction

21. American Chemical Society Liquid Characteristics of a liquid on the molecular level The molecules of a liquid move at a certain speed at room temperature. The attractions between the molecules are strong enough to keep them close together at that speed. Adding energy (heating) makes molecules move faster, causing them to move a little further apart. Removing energy (cooling) makes molecules move slower, causing them to move a little closer together.

22. American Chemical Society Lesson 1.3 An Application of Molecular Motion in Liquids: Thermometers Students place a thermometer in hot and then cold water. Ask students to explain, on the molecular level: Why the liquid goes up when a thermometer is placed in hot water? Why the liquid goes down in cold water?

23. American Chemical Society How Thermometers Work Hot: faster, further apart, move up Cold: slower, closer together, move down

24. Let’s pause for questions from the audience

25. American Chemical Society Lesson 1.4 Molecular Motion in Solids Do the same principles that apply to liquids also apply to solids?

26. American Chemical Society Heating and Cooling a Solid Ask students: If solids are also made of atoms and molecules, try to explain why this happens on the molecular level.

27. American Chemical Society Solids vs. Liquids Assume that the solid and liquid are both at room temperature. Vibrate Attracted to each other Don’t move past each other

28. American Chemical Society Heating and Cooling a Solid Hot: faster, further apart Cold: slower, closer together Flexible joints in roads keep the road from cracking as it expands and contracts with changes in temperature.

29. American Chemical Society How are the Atoms of a Metal Attracted to Each Other? The atoms of a metal are attracted to one another in a way called “metallic bonding.” The outer electrons move between the metal atoms (positive ions). The attraction between the positive metal ions and the negative electrons holds the metal together as a solid.

30. American Chemical Society Solid Characteristics of a solid on the molecular level The atoms or molecules of a solid move at a certain speed at room temperature. The attractions are strong enough to keep them close together at that speed and to hold them in fixed positions as a solid. Adding energy (heating) increases the motion of the atoms causing them to move a little further apart. Removing energy (cooling) decreases the motion of the atoms causing them to move a little closer together.

31. Let’s pause for questions from the audience

32. Gases Are Matter, Too American Chemical Society Air is made up of molecules of different gasses. It is about 78% nitrogen and about 20% oxygen. These molecules have mass and take up space.

33. American Chemical Society Lesson 1.5 Molecular Motion in Gases Very far apart Very weak attractions

34. American Chemical Society Heating and Cooling a Gas The mouth of an “empty” bottle is dipped into a detergent solution. The bottom of the bottle is placed in hot water and then in cold water. On the molecular level, why does this happen?

35. Modeling Heating and Cooling a Gas American Chemical Society Outside air pressure is the same on both. The faster-moving molecules in the heated sample push harder against the air pressure and expand the bubble. The slower-moving molecules in the cooled sample push less hard against the air pressure, which causes the bubble to contract.

36. American Chemical Society Heating and Cooling a Gas Warmer, faster moving molecules push harder from the inside against the bubble film than the air pressure pushes from the outside. Cooler, slower moving molecules don’t push as hard as the outside air pressure, which pushes the bubble down.

37. Why Are the Molecules of the Gases in Air Not Attracted to Each Other? American Chemical Society Nitrogen gas (N 2 ) Oxygen gas (O 2 ) Nitrogen (N 2 ) and oxygen (O 2 ) gas are made of two identical atoms bonded together. Each atom attracts the electrons of the other equally. There is no polarity like in the water molecule.

38. American Chemical Society Gas Characteristics of a gas at the molecular level The molecules of a gas move at a certain speed at room temperature. The attractions between the molecules are not strong enough at that speed to keep them close together as a liquid or a solid; therefore, they move independently as a gas. Adding energy (heating) increases the motion of the molecules and, if they can, they move further apart. Removing energy (cooling) decreases the motion of the molecules and, if pushed on hard enough, they move closer together.

39. Student Understanding - Balance Between Attraction and Motion 39 Different substances are solid, liquid, or gas at a particular temperature because of a balance between the attractions of the atoms or molecules of the substance and their motion at that temperature. Poor Understanding Moderate Understanding Good Understanding American Chemical Society

40. Do the Lessons Align with the New National Framework for Science Education? Disciplinary Core Ideas The position and motion of atoms or molecules in a solid, liquid, and gas. Science and Engineering Practices Developing and using models. Planning and carrying out investigations. Constructing explanations based on evidence. Crosscutting Concepts Cause and effect: Adding or removing energy (heating and cooling) causes changes in the motion of molecules. Systems and system models: Students model substances as systems composed of particles.

41. American Chemical Society For more resources … www.middleschoolchemistry.com For more information, contact us at k8education@acs.org

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