1 / 61

Thursday, October 31, 2013

Thursday, October 31, 2013. Happy Halloween! Standard IE1: Scientific progress is made by asking meaningful questions and conducting careful scientific experiments. Independent Practice: Section 3.3 Reading Packet Question: Copy the chart into your Journal. Measurements and Calculations.

halen
Download Presentation

Thursday, October 31, 2013

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Thursday, October 31, 2013 • Happy Halloween! • Standard IE1: Scientific progress is made by asking meaningful questions and conducting careful scientific experiments. • Independent Practice: • Section 3.3 Reading Packet • Question: Copy the chart into your Journal.

  2. Measurements and Calculations

  3. Units of Measurement • Measurements involve NUMBER and UNIT • Represent a quantity: has magnitude, size, or amount • Gram = unit of measurement • Mass = quantity

  4. Units of Measurement • Scientists around the world agree on one system… • International System of Units (le Systeme International d’Unites) • SI units • Built from seven base units

  5. SI Base Units

  6. Units of Measurement

  7. Units of Measurement • Metric Prefixes – make units easier to use • Make the unit smaller or larger • Unit = prefix + base unit • Table pg. 74

  8. Mass • Measures quantity of matter • SI unit: kilogram, kg • ______ kg = _____ g • gram used for smaller masses • Weight: measure of gravitational pull

  9. Length • SI unit: meter, m • Longer distances: kilometer, km • _______ km = _______ m • Shorter distances: centimeter, cm • _______ m = ________ cm

  10. Volume • SI unit: m3 • A derived unit: combination of base units by multiplying or dividing • SI unit for Area: l x w = m x m = m2 • Volume: l x w x h = m x m x m = m3 • Also: liters (L), mL, dm3 and cm3 • 1 L = 1 dm3 = 1000mL = 1000 cm3

  11. Derived Units

  12. Scientific Notation • Put the numbers in the form a x 10n • a has one # to left of decimal • If # is bigger than 1  + exponent • If # is less than 1  - exponent

  13. Scientific Notation • Review: Write in scientific notation or standard notation. a. 32,700 b. 0.0003412 c. 3.901 x 10-6 d. 4.755 x 108

  14. Let’s Practice Scientific Notation Worksheet

  15. 1 2 3 4 5 Significant Figures (Sig Figs) • How many numbers mean anything? • When we measure, we can (and do) always estimate between the smallest marks.

  16. Significant Figures (Sig Figs) • Better marks better estimate. • Last number measured actually an estimate 1 2 3 4 5

  17. Rules for Significant Figures • All nonzero digits are significant. • 457 cm has 3 sig figs • 2.5 g has 2 sig figs • Zeros between nonzero digits are significant. • 1007 kg has 4 sig figs • 1.033 g has 4 sig figs • Zeros to the left of the first nonzero digit are not significant. They are not actually measured, but are place holders. • 0.0022 g has 2 sig figs • 0.0000022 kg has 2 sig fig • Zeros at the end of a number and to the right of a decimal are significant. They are assumed to be measured numbers. • 0.002200 g has 4 sig figs • 0.20 has 2 sig figs • 7.000 has 4 sig figs • When a number ends in zero but contains no decimal place, the zeros may or may not be significant. We use scientific (aka exponential) notation to specify. • 7000 kg may have 1, 2, 3 or 4 sig figs!

  18. Sig Figs • What is the smallest mark on the ruler that measures 142.15 cm? • 142 cm? • 140 cm? • Does the zero mean anything? (Is it significant?) • They needed a set of rules to decide which zeroes count.

  19. Sig Figs. • 405.0 g • 4050 g • 0.450 g • 4050.05 g • 0.0500060 g

  20. Sig Figs • Only measurements have sig figs. • Counted numbers are exact – infinite sig figs • A dozen is exactly 12 • Conversion factors: 100 cm = 1 m

  21. Problems • 50 has only 1 significant figure • if it really has two, how can I write it? • Scientific notation • 5.0 x 101 2 sig figs • Scientific Notation shows ALL sig figs

  22. Rounding Rules • Round 454.62 to four sig figs • to three sig figs • to two sig figs • to one sig fig

  23. Sig Figs • How many sig figs in the following measurements? • 458 g • 4085 g • 4850 g • 0.0485 g • 0.004085 g • 40.004085 g

  24. Let’s Practice Significant Figures Worksheet

  25. Journal - Wednesday, November 6, 2013 • Standard IE1: Scientific progress is made by asking meaningful questions and conducting careful scientific experiments. • Independent Practice: • Significant Figures Worksheet (#2) • Question: Copy the chart into your Journal. (next slide)

  26. OPEN NOTE Quiz!! • When? • Blocks 1 and 3: Wednesday, November 13, 2013 • Blocks 2 and 4: Thursday, November 14, 2013 • Topics Included: • SI Units • Scientific Notation • Significant Figures • Significant Figures in Calculations • Density • Conversions

  27. Vocabulary Review • Calibration: a set of graduations to indicate values or positions. • Precision: Describes the closeness, or reproducibility, of a set of measurements taken under the same conditions. • Convey: To make something known to someone. • Significant: Very important. • Intervals: A period of time between events.

  28. Review:Scientific Notationand Significant Figures Worksheets

  29. Calculations with Significant Figures Rules Annotate the Reading

  30. Calculations with Sig Figs • 165.86 g + 4.091g - 140 g + 27.32 g • (35.6 L + 2.4 L) / 4.083 = • 2.524 x (16.408 m – 3.88 m) = Answers: 57g 9.31 L 31.62 m

  31. Let’s Practice Significant Figures in Calculations WS

  32. Density • Density = mass D = m volume V • Units: g/cm3 or g/mL but SI unit is kg/m3 • derived unit • Used to identify substances • Varies with temperature • As temp. increases density…

  33. Density

  34. Density Examples • If a metal block has a mass of 65.0 grams and a volume of 22 cubic centimeters, what is the density of the block? • D = m V • D = 65.0 g = 3.0 g/cm3 22 cm3

  35. Density Examples • Aluminum has a density of 2.7 g/cm3. What volume of aluminum has a mass of 60 grams? • D = M V 20 cm3

  36. Density Examples • Gold has a density of 19.3 g/cm3. A block of metal has a mass of 80 g and a volume of 12 cm3. Could this block be a piece of gold? • No, because this block has a density of 7 g/cm3s

  37. Unit Conversions

  38. Unit Conversions • Given information in one unit  need to find the equivalent in another unit • Identify what’s given • Organize plan of attack • Carry out plan WITH UNITS!!

  39. Conversion factors • “A ratio of equivalent measurements.” • Start with two things that are the same. 1 m = 100 cm • Can divide by each side to come up with two ways of writing the number 1.

  40. 1 m 100 cm 100 cm 100 cm Conversion factors =

  41. Conversion factors 1 m = 1 100 cm

  42. 1 m = 100 cm 1 m 1 m Conversion factors 1 m = 1 100 cm

  43. Conversion factors 1 m = 1 100 cm = 100 cm 1 1 m

  44. Conversion Factors • Unique way of writing the number 1. • Does NOT change the VALUE, it changes the UNITS.

  45. Write the conversion factors for the following • kilograms to grams • feet to inches • 1 L = 1 dm3 = 1000mL = 1000 cm3

  46. Let’s See How They Work • We can multiply by a conversion factor creatively to change the units . • 13 inches is how many yards?

  47. Let’s Try Some! • 323 mm = _____ nm • 3.2 miles = _____ in • 250 gallons = _____ mL • 15 days = _______ min

  48. More Unit Conversions More Involved

  49. Derived Unit Conversions • 54.3 cm3 = ______ m3 • 7.54 ft2 = _______ in2

More Related