Presentation on theme: "SN Starter A group of students are asked to express this number"— Presentation transcript:
1 SN Starter A group of students are asked to express this number ( ) to three significant figures. Which of thefollowing are correct?.0033.048 x 1033.05 x 10-3.00305d. and e. are both correct.
2 Conversions Converting From One System of Units to Another You will need a conversion factor like ( 1 meter = 3.28 ft).It can be used two ways:(1m/3.28ft) or ( 3.28ft/1m)Multiply your given dimension by the conversion factor to obtain the desired dimension.How many feet in 2 meters? m (3.28ft/m) = 6.56 feetHow many meters in 10 feet? ft(1m/3.28ft) = 3.05 meters
3 Converting AreasTo convert areas, you must square the conversion factor.Conversion factor: 1 inch = 2.54cmA page is 8.5 inches by 11 inches. What is the area in square centimeters?The area in square inches is 95 in2. So……95 in2 = __________cm295 in2(2.54cm/1 in)2 = 95(6.45 cm2) / (1 in2) = 613 cm2
4 Converting VolumesTo convert volumes, you must cube the conversion factor.A cubic foot is how many cubic inches?Conversion factor: 1 foot = 12 inches1 ft 3 ( 12 in/ 1 ft)3 = 1 ft 3 ( 123 in3/ 13 ft3) = 1728in3
6 Examples 12nm = 12 x 10-9 m Finished. Change 12nm to meters. n = x 10-9 so replace it:12nm = 12 x 10-9 m Finished.
7 Examples 250g ( 1 kg/1x103 g) = .250 kg Change 250 grams to kilograms. 1 kg = 1x103 gram250g ( 1 kg/1x103 g) = kg
8 Scientific NotationIf numbers are very large, like the mass of the EarthkgOr very small like the mass of an electron :kgthen standard decimal notation is very cumbersome,so we use scientific notation.
9 Scientific Notation Example: 5.9 x 1024 Example: 6.2 x 10-4 A number in scientific notation has two parts:1st part: a number between 1 and 102nd part: 10 to some power.Example: x 10241024 Means move the decimal 24 places to the right.Example: x 10-410-4 Means move the decimal 4 places to the left.
10 Examples – Put the number in Scientific Notation Answer: = 3.45 x 105bAnswer: = 3.4 x 10-4
12 Examples Simplify: (2 x 103)(4 x 106) = (2)(4) x 103(106) = 8 x 109
13 Significant FiguresHow to count the number of significant figures ina decimal number.Zeros Between other non-zero digits are significant.a has three significant figuresb has five significant figures
14 Significant FiguresZeros in front of nonzero digits are not significant:0.892 has three significant figureshas one significant figure
15 Significant FiguresZeros that are at the end of a decimal number are significant.57.00 has four significant figureshas seven significant figuresAt the end of a non-decimal number they are not.5700 has two significant figures2020 has three significant figures
16 Non-Decimal NumbersMajor pain to try to figure out the significant figures – it depends on the number’s history. Don’t Use Them.
17 SN Practice Find the number of significant figures. 2.00450 .0034050 14506 sf’s.5 sf’s3 sf’s4 sf’s
18 Significant Figures After Division and Multiplication After performing the calculation, note the factor that has the least number of sig figs. Round the product or quotient to this number of digits.3.22 X 2.1 = 6.836.5/3.414 = 10.7
19 Significant Figures Addition or subtraction with significant figures: The final answer should have the same number of digits to the right of the decimal as the measurement with the smallest number of digits to the right of the decimal.Ex:= 103.2