1. 6/30/03Prof. Lynn Cominsky1 Properties of Matter Part 1 NBSP Physical Science Leadership Institute Monday June 30, 2003

2. 6/30/03Prof. Lynn Cominsky2 Standard Connections Properties of matter can be observed, measured and predicted (K) As a basis for understanding this concept, students know that objects can be described…on the basis of physical properties such as WEIGHT What are the common properties that scientists use to describe matter?

3. 6/30/03Prof. Lynn Cominsky3 First Activity: Measuring matter How do we measure mass? How do we know when 2 objects have the same mass? Assemble a balance. Sketch it in your notes, and label the parts of the balance. Experiment with the objects to see how the balance operates.

4. 6/30/03Prof. Lynn Cominsky4 Equipment for first activity Plastic balance Pans Set of random objects Lots of washers

5. 6/30/03Prof. Lynn Cominsky5 Further investigations: Does it make a difference where the objects are placed in the pans? Does it make a difference if you switch the objects and place them in different pans? Does it make a difference if you use a different balance? What does it mean when we say something is in balance?

6. 6/30/03Prof. Lynn Cominsky6 Operational Definitions An operational definition describes the process that is used to make a measurement It should be able to be used by another individual to repeat the measurement process using the same (or similar) equipment

7. 6/30/03Prof. Lynn Cominsky7 Questions for the second activity: How do we establish a set of standard masses? Can you write an operational definition for mass? Equipment for the second activity: Small pan balances Standard mass sets

8. 6/30/03Prof. Lynn Cominsky8 Mass activity #2 Use nuts to measure the mass of an object in your set Measure the mass of a single washer using the standard mass set Measure the object using the standard mass set – did the results make sense? Use the standard mass set to measure a different object Predict how many washers it would take to balance this object – did it work?

9. 6/30/03Prof. Lynn Cominsky9 Thought experiment First weigh one object, and then weigh a second object. If you now put both objects on the scale at the same time, how will the total mass compare to the sum of your first two measurements?

10. 6/30/03Prof. Lynn Cominsky10 Key concepts about mass Mass is a property of matter that can be measured using a standard set of objects. The typical standard that is used to measure mass is the gram. In most everyday situations, mass is conserved. M 1 + M 2 = M 1+2

11. 6/30/03Prof. Lynn Cominsky11 Vocabulary for ELL Equal-arm Balance: a physical instrument used to measure mass by comparing items Mass:property of matter that describes its quantity Gram:standard unit of measurement for mass Standard mass set: Set of masses which have a known relationship to one another Weight: result of gravity acting on mass

12. 6/30/03Prof. Lynn Cominsky12 ELD Activities Compare masses of different objects in the classroom Make a table to help remember new words: WordDefinition How I remember

13. 6/30/03Prof. Lynn Cominsky13 Publisher’s Materials Take some time to look through the state-adopted texts to find activities relating to measuring and observing objects Examples: HC p. C5

14. 6/30/03Prof. Lynn Cominsky14 Break – some things to think about What is the difference between mass and weight? How would your mass change if you lived on the Moon? How would your weight change?

15. 6/30/03Prof. Lynn Cominsky15 Standard Connections Students know that objects can be described…on the basis of physical properties such as SHAPE How do we measure volume? How do we know when 2 objects have the same volume? How does measuring volume compare to measuring mass?

16. 6/30/03Prof. Lynn Cominsky16 Third Activity – Volume of a Solid Given: a large block and lots of smaller cubes Use the cubes to make a model of the large block Count the number of cubes that it takes to make your model Repeat for several different objects Is volume always = length x width x height?

17. 6/30/03Prof. Lynn Cominsky17 Fourth activity: Volume and Liquid How do we measure the volume using a liquid? What is the relationship between 1 cm 3 and 1 mL? Graduated cylinders Water Plastic cubes and other objects Equipment for Fourth activity

18. 6/30/03Prof. Lynn Cominsky18 Fourth activity: Volume and Liquid Fill the graduated cylinder to the 35 mL mark. Drop in 7 of the plastic cubes. Measure each cube with a ruler. How much does the water level rise? How could you put marks on the side of the cylinder if they were not already there? Write an operational definition for volume

19. 6/30/03Prof. Lynn Cominsky19 More questions about volume and mass: How would you measure the volume of an irregularly shaped object if it was too large to fit into a graduated cylinder? Does each gram of a submerged object displace a gram of water? Could we measure the mass of a submerged object by the water displacement method?

20. 6/30/03Prof. Lynn Cominsky20 Thought experiment Suppose a graduated cylinder is filled up to the 50 mL mark with dry sand. Then suppose that 30 mL of water is poured into the cylinder. Will the final volume of the water and sand be measured at 80 mL? Explain your reasoning.

21. 6/30/03Prof. Lynn Cominsky21 Key concepts Volume – is measured using a standard set of objects such as uniform cubes, or by measuring a liquid such as water, which is displaced by the object to be measured Volume is NOT conserved: V 1 + V 2 is not necessarily equal to V 1+2

22. 6/30/03Prof. Lynn Cominsky22 Volume: the amount of space that an object displaces Graduated Cylinder: A physical instrument used to measure volume of liquids (directly) or of solids (by submersion) Vocabulary for ELL

23. 6/30/03Prof. Lynn Cominsky23 ELD Activities There are at least two volumes associated with a tin can. What are they are and how would you measure each?

24. 6/30/03Prof. Lynn Cominsky24 Publisher’s Materials Take some time to look through the state-adopted texts to find activities relating to measuring volume that could be used in your classroom.

25. 6/30/03Prof. Lynn Cominsky25 Lunch break - Things to think about Consider the two boxes shown. Their dimensions are given in meters. Answer the following questions about the boxes. Explain your reasoning. 3 6 2 2 3 3 Box A Box B

26. 6/30/03Prof. Lynn Cominsky26 Lunch break questions: Suppose these boxes, including their lids, are made of very thin plywood. Which box requires more wood? Which box will hold more peanuts? Which box is heavier (empty)? Which box would say is bigger and why?

27. 6/30/03Prof. Lynn Cominsky27 Standard Connections Students know that objects can be described…on the basis of physical properties such as FLOATING & SINKING How do we measure density? How can we tell if an object will sink or float?

28. 6/30/03Prof. Lynn Cominsky28 Key concepts: density Density is defined as the mass of an object divided by its volume Density is a characteristic property of an object: under the same conditions, all objects made of the same material have the same density The units for density are g/cm 3 – The value tells you how many grams are in one cubic centimeter of material

29. 6/30/03Prof. Lynn Cominsky29 Thought experiment: Density A block of wood has a mass of 18 g and a volume of 25 cm 3 How would you interpret the number 18/25? How would you interpret the number 25/18? Write an operational definition for density

30. 6/30/03Prof. Lynn Cominsky30 Fifth Activity: Sinking and Floating Given: a set of objects, and a beaker of water. Water’s density is 1 g/cm 3 Predict whether your objects will sink or float, then test out your predictions Can you turn any sinkers into floaters? Floaters into sinkers? Separate the sinkers and floaters into separate groups

31. 6/30/03Prof. Lynn Cominsky31 Fifth Activity: Sinking and Floating What similarities are there among the objects that floated? What differences? What similarities are there among the objects that sank? What differences? Make a list of things that you believe influence whether or not an object can float How will you test your ideas about sinking and floating?

32. 6/30/03Prof. Lynn Cominsky32 Sixth activity: Why does a boat float? Tear off two pieces of aluminum foil that are approximately the same size Make one into a boat Crumple the second one up into a ball Measure the mass of each piece Drop each into the pan of water What happens?

33. 6/30/03Prof. Lynn Cominsky33 Sixth activity: Why does a boat float? Can you determine the density of each piece? Why or why not? Predict how many washers you can add to the boat before it will sink. Test out your prediction. Does the mass effect whether an object sinks or floats? Does the volume?

34. 6/30/03Prof. Lynn Cominsky34 Key concepts: Sinking and Floating When an object is totally submerged in a liquid, it displaces a volume of the liquid equal to its volume If the object is floating in a liquid, it displaces a volume of the liquid which has the same mass as the entire object If you know the density of both the object and the liquid, you can calculate how much of the object is submerged in the liquid

35. 6/30/03Prof. Lynn Cominsky35 Math connections An ice cube with volume of 1 cm 3 has a density of 0.9 g/cm 3 It is floating in very salty water that has a density of 1.2 g/cm 3 What is the mass of the ice cube? What is the mass of the salty water that it displaces? What is the volume of the water that it displaces? How much of the ice cube floats above the water?

36. 6/30/03Prof. Lynn Cominsky36 Vocabulary for ELL Sinking: when an object is entirely covered with liquid Floating: when only part of the object is covered with liquid

37. 6/30/03Prof. Lynn Cominsky37 ELD Connections When someone is slow to understand, they may be called dense. Why? When someone is feeling sad, they are said to have a sinking feeling. Why? When someone is feeling happy, they are said to be floating on air. Why?

38. 6/30/03Prof. Lynn Cominsky38 Publisher’s Materials Take some time to look through the state-adopted texts to find activities relating to sinking and floating that could be used in your classroom. Examples: HM p. 198, HM p. C7

39. 6/30/03Prof. Lynn Cominsky39 Break – things to think about You are sitting in a boat which is floating in a small pond. Next to you, inside the boat, is a large rock. The density of this rock is 10 g/cm 3. You pick up the rock and throw it over the side of the boat. Does the water level in the pond go up, stay the same or go down? Explain your answer.

40. 6/30/03Prof. Lynn Cominsky40 Standard Connections Students know that objects can be described…on the basis of physical properties such as ATTRACTION TO MAGNETS What types of materials are attracted to magnets? How can we tell the difference between a magnet and a metal? Are any materials repelled from magnets?

41. 6/30/03Prof. Lynn Cominsky41 Equipment for third activity Magnets of various sizes and shapes Some pieces of non-magnetized metal Other things like rubber, wood, glass, plastic, aluminum, paper clips, etc. Seventh activity: Exploring magnets Use different magnets and bag of objects to explore magnetic properties

42. 6/30/03Prof. Lynn Cominsky42 A few things to try: Bring pairs of like and unlike magnets together at different locations Play with magnets and pieces of metal like paper clips Play with magnets and other materials What common properties do objects have that are attracted to magnets? Some things on your own!

43. 6/30/03Prof. Lynn Cominsky43 Key concepts Metals are always attracted to magnets Magnets are both attracted and repelled from other magnets Some metals are more strongly magnetic than others – iron is typically used for magnets Some parts of the magnet are more magnetic than others

44. 6/30/03Prof. Lynn Cominsky44 Vocabulary for ELL n Magnet: material that can both attract and repel other magnets. Iron is most common. n Pole: Part of the magnet where the force is the strongest n Metal: material that is often attracted to magnets and a good electrical conductor n Horseshoe magnet: U-shaped magnet NS

45. 6/30/03Prof. Lynn Cominsky45 Publisher’s Materials Take some time to look through the state-adopted texts to find activities relating to magnets that could be used in your classroom. Examples:

46. 6/30/03Prof. Lynn Cominsky46 ELD Activities Make a list of things that are attracted to magnets Make a list of things that have magnets in them Why do we say that some people have magnetic personalities?

47. 6/30/03Prof. Lynn Cominsky47 Take away – brain teaser Someone gives you 2 bars of identical shape, weight and appearance One is a magnet and the other one is metal How can you tell which is which? (You can’t use any other equipment, you can’t touch the bars to anything but each other and you don’t know which way North is located.)

48. 6/30/03Prof. Lynn Cominsky48 Lesson Study Activities Identify a key concept from today’s lecture for further development Review the publisher’s materials about this key concept Discuss the best way to present this key concept in your classroom

49. 6/30/03Prof. Lynn Cominsky49 Resources Physics by Inquiry – L. McDermott and the PEG at U Washington