Daily Review Tell the difference between accuracy and precision. Give an example. Record 56,489.23 in scientific notation. Record 0.0025050 in scientific notation. What is the formula for percent error?

Significant Figures and Metric units Chapter 3

Learning Objectives You will need to be able to: Determine the number of significant figures in a number. Calculate using significant figures Round using significant figures

Significant Figures In a measurement the last digit is considered to be an estimate (guess). Significant figures in a measurement include those numbers that are known plus one estimates digit.

Significant Figure Rules 1) ALL non-zero numbers (1,2,3,4,5,6,7,8,9) are ALWAYS significant. EX: 12.543 has 5 Sig. Figs. 2) ALL zeroes between non-zero numbers are ALWAYS significant. “Captured Zeros” EX 1.02 has 3 Sig. Figs. 3) ALL zeroes which are SIMULTANEOUSLY to the right of the decimal point AND at the end of the number are ALWAYS significant. “Place Holders” EX: 0.0023 has 2 Sig. Figs. EX: 100 has 1 Sig. Fig. 4) ALL zeroes which are to the left of a written decimal point and are in a number >= 10 are ALWAYS significant. “Trailing Zeros” EX: 12.00 has 4 Sig. Figs.

Practice: Sig. Figs. Determine the number of significant digits in each of the following: 6.571 g b) 0.15070 kg c) 28.0 ml d) 2500 e) 0.0700000 g Answers 4 5 3 2 6

Ten-Two In your notebook: Take two minutes to summarize what you have learned to far!

Significant Figures: Rules for Calculation Rule #1:ADDITION AND SUBTRACTION: When adding or subtracting numbers, count the NUMBER OF DECIMAL PLACES to determine the number of significant figures. Record your answer using the FEWEST NUMBER of decimal places 23.112233 (6 places after the decimal) 1.3324 (4 places after the decimal) + 0.25 (2 places after the decimal) 24.694633 (on calculator) Answer: 24.69 (rounded to 2 places in the answer)

Significant Figures: Rules for Calculation Rule #2 MULTIPLICATION AND DIVISION: When multiplying or dividing numbers, count the NUMBER OF SIGNIFICANT FIGURES. Record your answer using the SMALLEST number of significant figures 23.123123 (8 significant figures) x 1.3344 (5 significant figures 30.855495 (on calculator) Answer 30.855 (rounded to 5 significant figures)

Practice: Sig. Figs. Using the rules for Significant figures calculate the following and record using the correct significant figures. 16.5 + 8 + 4.37 13.57 - 6.3 3.15 x 2.5 x 4.00 40.8 / 5.05 Answers 21 7.3 32 8.08

Measurement Activity

Sigs. Figs Daily Review What are significant figures? Why are significant figures important? How many significant figures are in the number 0.2304? 1.1200? Calculate using the correct number of significant figures. 2.3 x 1.23 12.3 + 1.33 + 4.2569 Sigs. Figs

Learning objectives You will need to be able to: Understand the SI base units and their abbreviations Use prefixes and convert between metric units Understand measurement abbreviations.

Early Measurement What do you find right or wrong with these forms of measurements?

The International System of Units

Prefixes for the SI System

Practice What is the unit of measurement for length? What is the unit of measurement for count or quantity of a substance? What is the base unit for temperature? What is the base unit for mass? Meter Mole Kelvin Kilogram

Practice Give the abbreviation for the following measurement units: centiliter Millimeter Megagram picosecond deciliter Answers cL mm Mg ps dL

How many jumps does it take? Ladder Method 1 2 3 KILO 1000 Units HECTO 100 Units DEKA 10 Units DECI 0.1 Unit Meters Liters Grams CENTI 0.01 Unit MILLI 0.001 Unit How do you use the “ladder” method? 1st – Determine your starting point. 2nd – Count the “jumps” to your ending point. 3rd – Move the decimal the same number of jumps in the same direction. 4 km = _________ m Starting Point Ending Point How many jumps does it take? 4. 1 __. 2 __. 3 __. = 4000 m

Practice: Metric conversions Convert these using the diagram 1000 mg = _______ g 1 L = _______ mL 160 cm = _______ mm 14 km = _______ m 109 g = _______ kg 250 m = _______ km

Thinking log On a post-it note: The hardest part of the lesson was_______________ I was successful in ___________________