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Unit Conversion. “Hard work has made it easy. That is my secret. That is why I win” Nadia Comaneci Olympic gymnast. Unit Conversion. Learning Target ‘GUESS’ procedure Students learn how to: 1) Convert between metric and non-metric units e.g. meters and yards
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Unit Conversion “Hard work has made it easy. That is my secret. That is why I win” Nadia Comaneci Olympic gymnast
Unit Conversion Learning Target • ‘GUESS’ procedure Students learn how to: 1) Convert between metric and non-metric units e.g. meters and yards 2) Convert between metric units e.g. meters and kilometers 3) Do multi-step conversion problems e.g. seconds to years
Challenge Question How many seconds are there in 1 year? * reminder: bring your calculator to class every day this semester
Unit Conversion Why important? Youtube: When NASA Lost a Spacecraft Because It Didn't Use Metric - It Happened in Space #21 Re-Read sec 1.2 p. 10-15Units of measurement and intro to unit conversion.
1.2 Unit Conversion:non-metric metric How many centimeters is 5 feet? (1 foot = 30 centimeters) ANS = 150 centimeters
Unit Conversion Notes: The unit you are converting from goes in the bottom(top/bottom?) of the conversion factor The unit you are converting to goes in the top(top/bottom?) of the conversion factor See ‘Skills Toolkit’ p. 13 Youtube: Tyler DeWitt - Converting Units with Conversion Factors https://www.youtube.com/watch?v=7N0lRJLwpPI
GUESS Procedure Given Unknown Equation Substitute Solve
Unit Conversion:metric non-metric A bicycle has its frame size given as 62 cm. What is the frame size in inches? (1 inch = 2.54 cm) *Note: metric to non-metric conversion factors will always be given to you ANS = 24 inches
Significant Figures Significant figures tell you the accuracy with which a measurement was made e.g. 62 cm OR 62.001 cm Suggested reading Sec 2.3 Measurements and Calculations p. 54-63
Significant Figures – multiplication & division Notes: The number of sig figs in your answer….. is the same as the number of sig figs in the ‘given’
Significant Figures – multiplication & division Notes: * If there is more than one given….. the number of sig figs in your answer….. is the same as the number of sig figs in the ‘given’ …. which has the least(least/most) number of sig figs e.g. 2.2 x 5.0451363 = 11.099299? ANS = 11 (2 sig figs) (rounding)
Significant Figures – Exact Values* Conversion factors have an infinite number of significant figures e.g. 1 m = 100 cm 1.00000000 m = 100.000000000 cm
Practice: scratch paper The distance between Los Angeles and San Diego is about 124 miles. How many kilometers is the distance between the two cities(1 mile = 1.6 km) ANS = 198 kilometers
1.2 Prefixes Think about it….... How many grams are there in 1 kilogram?
Dimensional AnalysisScratch paper work 1) Convert 1258 cm to meters ANS = 12.58 m 2) Convert 234g to kg
1.2 Dimensional Analysis Practice 2) Convert 234g to kg ANS = 0.234 kg 3) Convert 123 km to m
1.2 Dimensional Analysis 3) Convert 123 km to meters. ANS = 123 000 m 4) How many milligrams are there in 4.3 kg?
1.2 Dimensional Analysis 4) How many milligrams are there in 4.3 kg? First convert kg to g Then convert g to mg ANS = 4 300 000 mg Convert to scientific notation ANS = 4.3 x 106 mg
Scientific Notation When to use it? 16 = 1.6 x 101 • When a number is greater than 10000 • 34000 = 3.4 x 104 • When a number is smaller than 1/1000th • 0.00034 = 3.4 x 10-4
1.2 Dimensional Analysis: PracticeScratch paper work p. 14 # 1, 2, 3 p. 19 # 8, 9, 10* (* HONS: 1 cm3 = 1 mL) To check your answers, show work to teacher when complete
1.2 Dimensional Analysis: PracticeScratch paper work More practice: p. 32 # 22 a,b, & 23a,b,c,d*, e*, f* To check your answers, show work to teacher when complete Work sheet: One-Step Dimensional Analysis Problems
Challenge Question How many seconds are there in 1 year? ANS = 31 536 000 seconds ANS = 3.1536 x 107 seconds
Practice* Superman can run continuously at 62 miles per hour. How many miles can Superman run in one week? Write your final answer in scientific notation to 2 sig figs. ANS = 10416 miles/week
Dimensional Analysis*Scratch paper If the average heart rate is 72 beats per minute, approximately how many times will a heart beat in a year? • Given: average heart beat is 72 beats/min • Unknown:heartbeats per year (unit is beats/year)
Dimensional Analysis 72 beats/min X60 min/hour X24 hours/day X 365 days/year ANS = 37 843 200 beats/year Convert to scinotn (2 sig figs) 3.8 X107beats/year