Presentation on theme: "Unit Conversion SI units: The International System of Units (abbreviated SI from the French Système international d'unités]) is the modern form of the."— Presentation transcript:
1 Significant Figures, Scientific Notation, Unit Conversion, and Unit Magnitudes
2 Unit ConversionSI units: The International System of Units (abbreviated SI from the French Système international d'unités]) is the modern form of the metric systema system of units of measurement devised around seven base units and the convenience of the number ten
3 How to convert 1). Find your decimal point 2). Find your direction 3). Count your steps4). Move the decimal
4 Kilo Hecto Deca base Deci Centi Milli King Henry died by drinking chocolate milkExample: 12 Kilograms = _____ DecigramsDeci is 4 spaces to the left of Kilo so move the decimal 4 spaces to the right.Answer: 12 kg = g
5 Unit ConversionI will give you these conversion factors if you need them in a problem!1 inch = 2.54 cmexactly 1 lb = 454 g1 qt = L1 mi = 5280 ft1 qt = 2 pt4qt = 1 gal1 ounce = grams
6 Unit Conversions Convert 3598 grams into pounds. (exactly 1 lb = 454 g )
12 Extra Practice Practice on your own 1). 5 decimeters = mm 2). 14 hL = L3). 245 kilograms= mg4) mm= m
13 Scientific NotationScientific notation is simply a method for expressing, and working with, very large or very small numbers. -Numbers in scientific notation are made up of three parts: the coefficient, the base and the exponent.-EX: 5.67 x103 is the scientific notation for 5670-5.67 x 103 coefficient base exponent
14 Scientific Notation1. The coefficient must be greater than or equal to 1 and less than 10.2. The base must be 10.3. The exponent must show the number of decimal places that the decimal needs to be moved to change the number to standard notation. A negative exponent means that the decimal is moved to the left when changing to standard notation.
15 Converting to Scientific Notation Move decimal until there’s 1 digit to its left.-Places moved = exponent.Large # (>1) positive exponentSmall # (<1) negative exponentEX: Put in scientific notationPractice
16 Scientific Notation Adding and Subtracting Be sure that the exponents are the sameThen add or subtract the decimal number as listedMultiplication and DivisionTo multiply – multiply the first factors then add the exponentsTo divide – divide the first factors then subtract the exponent of the divisor from the exponent of the dividend
17 Scientific Notation Practice Write the following numbers in scientific notationmm438,904 sComplete the following addition and subtraction problems6.23 x 106 kL x 107 kL9.87 x 104 g – 6.2 x 103 gComplete the following multiplication and division problems(4.8 x 105 km) x (2.0 x 103 km)(8.4 x 106 L) ÷ (2.0 x 103 L)
18 Dimensional Analysis Dimensional Analysis Conversion Factor A tool often used in science for converting units within a measurement systemConversion FactorA numerical factor by which a quantity expressed in one system of units may be converted to another system
19 Dimensional Analysis The “Factor-Label” Method Units, or “labels” are canceled, or “factored” out
20 Dimensional Analysis Steps: 1. Identify starting & ending units. 2. Line up conversion factors so units cancel.3. Multiply all top numbers & divide by each bottom number.4. Check units & answer.
21 Dimensional Analysis Practice How many seconds are in 1.4 days?Plan: days hr min seconds1.4 days x 24 hr x 60 min x 60 sec =1 day hr minsec
22 Density Calculate density and use density to identify pure substances Ratio of mass to volumeDirectly proportional measure of how tightly matter is packedSubstances can be identified by comparing densities to known densitiesdensity (D) = mass (m) / volume (V)Expressed in g/mLDensity can be calculated by measuring the change in volume by a specifically measured mass
23 Density PracticeA 5-mL sample of water has a mass of 5 g. What is the density of water?An object with a mass of 10 g raises the level of water in a graduated cylinder from 25.1 mL to 30.1 mL. What is the density of the object?The density of aluminum is 2.7 g/mL. What is the volume of 8.1 g?
24 Accuracy and Precision EQ: In what ways do proper techniques contribute to reliable results?
25 Accuracy & PrecisionDistinguish between accuracy and precision in measurementAccuracy – extent to which a measurement approaches the true value of a quantityAgreement of a measurement with the accepted value of the quantityPrecision – degree of exactness or refinement of a measurementHow close a series of measurements are to one another.
26 France vs. ItalyItaly converts all five penalty kicks to win championship
27 A 41-year-old New York man who underwent two operations – one to remove a blood clot from the left side of his brain, and another when doctors discovered the clot was on the right side of his brain. The mistake? The patient's brain scan had been hung up backwards for viewing in the operating room.
31 % Error Calculating percent error % error = theoretical – actual x 100 The accepted length of a steel pipe is 5-m. Calculate the percent error for each of these measurements5.25 m4.75 m5.5 m
32 Sig Figs Rules recognizing significant figures Non-zero numbers are always significantZeros between non-zero numbers are always significantAll final zeros to the right of the decimal place are significantZeros that act as placeholders are not significant. Convert quantities to scientific notation to remove placeholder zerosCounting numbers and defined constants have an infinite number of significant figures
33 Sig Figs Rounding Rules If the digit to the immediate right of the last significant figure is less than five, do not change the last significant figureIf the digit to the immediate right of the last significant figure is greater than five, round up the last significant figureIf the digit to the immediate right of the last significant figure is equal to five and is followed by a nonzero digit, round up the last significant figure if odd. If even, do not round up.
34 Sig Figs How many significant figures in the following measurements? 431,801 kg10,235.0 mgcmcgWrite the above in scientific notation to four significant figures
35 Sig Figs Rules for using significant figures in calculations Addition or SubtractionThe answer can have no more digits to the right of the decimal point than there are in the measurement with the smallest number of digits to the right of the decimal pointmmm = m = 2.21 X 101 m
36 Sig Figs Multiplication or Division The answer can have no more significant figures than there are in the measurement with the smallest number of significant digitsProblem:g/mL x 500. mL = g x 102g = 5.57 x 102g
37 Sig FigsRound the answers to each of the following problems to the correct significant figures7.31 x x 1038.54 x 10-3 – 3.41 x 10-4(2.4 x 102) x (3.26 x 104)(1.024 x 102) ÷ (5.12 x 101)