Catalyst 10/12/10

1. Catalyst 10/12/10 Knowing what you know about precision, answer the following questions: Of the numbers 1100 cm vs. 1100.0 cm • Which is more precise? • How precise is each number? • Why would you choose one or the other number? Objectives: Identify and convert between units of the SI System. Determine the number of significant figures in numbers.

2. Agenda 10/12/10 • Catalyst (5) • Quick Review of Procedures and behavior (10) • SI System notes & guided practice (15) • Significant figures notes and guided practice (15) Homework: Conversion worksheet & bring calculator tomorrow

3. New Procedures: Catalysts • Catalysts will have a grade for answers and the stamp which will be given for silently working on catalyst 2 minutes after the bell • Stampers who stamp students who are not working silently lose their points and will not stamp again • You my make up the catalyst question, but not the stamp-except for verified excused absences • Excused absences can be verified by having parents sign and put phone number in catalyst for the day

4. New Procedures: Behavior • Every warning/reminder/incidence of inappropriate behavior loses 1 point (up to 5 per day) • Every unexcused or unverified absence loses all points • Every tardy loses 2 points for the day

5. SI: Base Units

6. SI: Derived Units

7. Unit Conversions

8. The Metric System is based on sets of 10. 1 x 10 = 10 10 X 10 = 100 10 x 100 = 1,000

9. The mnemonic: Memorize this! Kids Have Dropped over Dead Converting Metrics.

10. “Staircase” Method Draw and label this staircase every time you need to use this method, or until you can do the conversions from memory

11. You must also know… …how to convert within the Metric System. Here’s a good device: On your paper draw a line and add 7 tick marks:

12. Next: Above the tick marks write the abbreviations for the King Henry pneumonic: k h d o d c m m l g Write the units in the middle under the “o”.

13. Let’s add the meter line: k h d o d c m km hm dam m dm cm mm L g

14. Let’s add the liter line: k h d o d c m km hm dam m dm cm mm kL hL daL L dL cL mL g Deca can also be dk or da

15. Let’s add the gram line: k h d o d c m km hm dam m dm cm mm kl hl dal l dl cl ml kg hg dag g dg cg mg

16. How to use this device: Look at the problem. Look at the unit that has a number. On the device put your pencil on that unit. Move to new unit, counting jumps and noticing the direction of the jump. 3. Move decimal in original number the same # of spaces and in the same direction.

17. Example #1: • Look at the problem. 56 cm = _____ mm Look at the unit that has a number. 56 cm On the device put your pencil on that unit. k h d u d c m km hm dam m dm cm mm

18. Example #1: Move to new unit, counting jumps and noticing the direction of the jump! k h d u d c m km hm dam m dm cmmm One jump to the right!

19. Example #1: Move decimal in original number the same # of spaces and in the same direction. 56 cm = _____ mm 56.0. One jump to the right! Move decimal one jump to the right. Add a zero as a placeholder.

20. Example #1: 56 cm = _____ mm 56cm = 560 mm

21. Example #2: • Look at the problem. 7.25 L = ____ kL Look at the unit that has a number. 7.25 L On the device put your pencil on that unit. k h d u d c m kl hl dal L dl cl ml

22. Example #2: • Move to new unit, counting jumps and noticing the direction of the jump! k h d u d c m kl hl dal L dl cl ml Three jumps to the left!

23. Example #2: (3) Move decimal in original number the same # of spaces and in the same direction. 7.25 L = ____ kL .007.25 Three jumps to the left! Move decimal to the left three jumps. Add two zeros as placeholders.

24. Example #2: 7.25 L = ____ kL 7.25 L = .00725 kL

25. Example #3: Try this problem on your own: 45,000 g = ____mg k h d u d c m kg hg dag g dg cg mg

26. Example #3: k h d u d c m kg hg dag g dg cg mg Three jumps to the right! 45,000.000.

27. Example #3: 45,000 g = 45,000,000 mg Three jumps to the right!

28. Example #4: Try this problem on your own: 5 cm = ____ km k h d u d c m km hm dam m dm cm mm

29. Example #4: k h d u d c m km hm dam m dm cm mm Five jumps to the left! .00005.

30. Example #4: 5 cm = .00005 km Five jumps to the left!

31. Factor-Label Method • Multiply original measurement by a conversion factor • A fraction that relates the original unit and the desired unit. • Conversion factor is always equal to 1. • Numerator and denominator should be equal measurements. • When a measurement is multiplied by a conversion factor, original units should cancel

32. Factor-Label Method: Example • Convert 6.5 km to m • First, we need to find a conversion factor that relates km and m. • We should know that 1 km and 1000 m are equivalent (there are 1000 m in 1 km) • We start with km, so km needs to cancel when we multiply. So, km needs to be in the denominator

33. Factor-Label Method: Example • Multiply original measurement by conversion factor and cancel units.

34. Factor-Label Method: Example • Convert 3.5 hours to seconds • If we don’t know how many seconds are in an hour, we’ll need more than one conversion factor in this problem

35. Examples #5-9: Solve these problems one by one on your whiteboard using one of the methods described. (5) 35 mm = ____ cm (6) 14,443 L = ____ kL (7) 0.00056 kg = ____ g (8)35.4 L = ____ mL (9)16 mm = ____ km

36. Counting Significant Figures

37. Calculating With Sig Figs

38. Calculating With Sig Figs

39. Practice Problems • Determine how many significant figures are in each of these numbers and problems • 2.03 • 0.0224 + 1.54 • 0.00471 - .003 • 10.00 * 2.0 • 5000000 / 10.000 • 1.078509700