Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the...

27
Standards of Measurements

description

Significant Figures All nonzero digits are significant.  1, 2, 3, 4, 5, 6, 7, 8, 9 Zeros within a number are always significant.  Both 4308 and have four significant figures.

Transcript of Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the...

Page 1: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Standards of Measurements

Page 2: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Accuracy and Precision

Accuracy – how close a measured value is to the actual value

Precision – how close the measured values are to each other

Page 3: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Significant Figures

All nonzero digits are significant. 1, 2, 3, 4, 5, 6, 7, 8, 9

Zeros within a number are always significant. Both 4308 and 40.05 have four significant figures.

Page 4: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Significant Figures

Zeros that set the decimal point are not significant. 470,000 has two significant figures. 0.000084 has two significant figures.

Trailing zeros that aren't needed to hold the decimal point are significant. 4.00 has three significant figures.

Page 5: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Significant Figures

If the least precise measurement in a calculation has three significant figures, then the calculated answer can have at most three significant figures.

Mass = 34.73 grams Volume = 4.42 cubic centimeters.

Rounding to three significant figures, the density is 7.86 grams per cubic centimeter.

Page 6: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Scientific Notation

For large numbers, moving the decimal to the left will result in a positive number 346500 = 3.46 x 105

For small numbers, moving the decimal to the right will result in a negative number 0.000145 = 1.45 x 10-4

For numbers less than 1 that are written in scientific notation, the exponent is negative.

Page 7: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Scientific Notation

Before numbers in scientific notation can be added or subtracted, the exponents must be equal. 5.32 x 105 + 9.22 x 104

5.32 x 105 + 0.922 x 105

5.32 + 0.922 x 105

6.24 x 105

Page 8: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Scientific Notation

When numbers in scientific notation are multiplied, only the number is multiplied. The exponents are added.

(3.33 x 102) (2.71 x 104) (3.33) (2.71) x 102+4

9.02 x 106

Page 9: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Scientific Notation

When numbers in scientific notation are divided, only the number is divided. The exponents are subtracted.

4.01 x 109

1.09 x 102

4.01 x 109-2 1.09

3.67 x 107

Page 10: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Scientific Notation

A rectangular parking lot has a length of 1.1 × 103 meters and a width of 2.4 × 103 meters. What is the area of the parking lot?

(1.1 x 103 m) (2.4 x 103 m) (1.1 x 2.4) (10 3+3) (m x m) 2.6 x 106 m2

Page 11: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

SI UnitsKilo- (k)

1000

Milli- (m)

Hecto- (h)

Deka- (da)

Base Unit

Deci- (d)

Centi- (c)

100

10

m, L, g

0.1

0.010.001Mnemonic device:

King Henry Died By Drinking Chocolate Milk

Page 12: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Metric System

Meter (m) – The basic unit of length in the metric system

Length – the distance from one point to another A meter is slightly longer

than a yard

Page 13: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Metric System

Liter (L) – the basic unit of volume in the metric system A liter is almost equal to a

quart

Page 14: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Metric System

Gram (g) – The basic unit of mass

Page 15: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Derived Units

Combination of base units Volume – length width height

1 cm3 = 1 mL Density – mass per unit volume (g/cm3)

D = MV D

MV

Page 16: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Density1) An object has a volume of 825 cm3 and a density of 13.6 g/cm3. Find its mass.

GIVEN:V = 825 cm3

D = 13.6 g/cm3

M = ?

WORK:M = DV

M = 13.6 g x 825 cm3

cm3 1

M = 11,220 gDM

V

Page 17: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Density2) A liquid has a density of 0.87 g/mL. What

volume is occupied by 25 g of the liquid?

GIVEN:D = 0.87 g/mLV = ?M = 25 g

DM

V

WORK:V = M DV = 25 g 0.87 g/mL

V = 28.7 mL

Page 18: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Density3) You have a sample with a mass of 620 g & a

volume of 753 cm3. Find the density.

GIVEN:M = 620 gV = 753 cm3

D = ?

DM

V

WORK:D = M VD = 620 g 753 cm3

D = 0.82 g/cm3

Page 19: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Dimensional Analysis / Unit Factors Dimensional analysis – a problem-solving

method that use any number and can be multiplied by one without changing its value

Page 20: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Dimensional Analysis / Unit Factors How many hours are there in a year?

There’s 8,760 hours in a year.

24 hr1 day

x 365 days1 year

= 8760 hr1 year

Page 21: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Dimensional Analysis / Unit Factors The distance from Grove Hill to Thomasville

is 15 miles. How many feet is that?

There’s 79,200 feet in 15 miles.

5280 ft1 mi

x15 mi1

= 79200 ft1

Page 22: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Dimensional Analysis / Unit Factors Convert 36 cm/s to mi/hr

3600 sec1 hrx36 cm

secx 1 in

2.54 cm1 ft

12 inx

=1 mi5280 ft

129600 mi160934.4 hr = 0.805 mi/hr

Page 23: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Temperature

A degree Celsius is almost twice as large as a degree Fahrenheit.

You can convert from one scale to the other by using one of the following formulas:

Page 24: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Temperature

Convert 90 degrees Fahrenheit to Celsius oC = 5/9 (oF - 32)

oC = 5/9 (90 - 32)

oC = 0.55555555555555556 (58)

oC = 32.2

Page 25: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Temperature

Convert 50 degrees Celsius to Fahrenheit oF = 9/5 (oC ) + 32

oF = 9/5 (50 ) + 32

oF = 1.8 (50) + 32

oF = 90 + 32

oF = 122

Page 26: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Temperature

The SI base unit for temperature is the kelvin (K). • A temperature of 0 K, or 0 kelvin, refers to the

lowest possible temperature that can be reached. • In degrees Celsius, this temperature is

–273.15°C. To convert between kelvins and degrees Celsius, use the formula:

Page 27: Standards of Measurements. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured values.

Temperature


ACCURACY & PRECISION IN MEASUREMENT

ACCURACY & PRECISION IN MEASUREMENT

Accuracy & Precision

Accuracy & Precision

IMPROVING ACCURACY AND PRECISION OF CALCULATED … · IMPROVING ACCURACY AND PRECISION OF CALCULATED PROCESS VARIABLES BY USING DIRECTLY MEASURED NONSUGARS . Jeffrey L. Carlson Gregory

IMPROVING ACCURACY AND PRECISION OF CALCULATED … · IMPROVING ACCURACY AND PRECISION OF CALCULATED PROCESS VARIABLES BY USING DIRECTLY MEASURED NONSUGARS . Jeffrey L. Carlson Gregory

Accuracy, Precision ppt

Accuracy, Precision ppt

V. Precision and Accuracy - University of South Carolina V. Precision and Accuracy Experimental Uncertainties If you want to get the most reliable value for a measured quantity, even

V. Precision and Accuracy - University of South Carolina V. Precision and Accuracy Experimental Uncertainties If you want to get the most reliable value for a measured quantity, even

Significant Figures Honors Chem section 1.5. Accuracy vs. Precision Accuracy: how close a measured value is to the true value. Precision: the degree of.

Significant Figures Honors Chem section 1.5. Accuracy vs. Precision Accuracy: how close a measured value is to the true value. Precision: the degree of.

Precision and accuracy in measurements Shows accuracy, but not precision Shows precision but not accuracy.

Precision and accuracy in measurements Shows accuracy, but not precision Shows precision but not accuracy.

Accuracy and Precision

Accuracy and Precision

Measurement. Objectives Make measurements with accuracy and precision. Identify and quantify causes and effects of uncertainties in measured data. Record.

Measurement. Objectives Make measurements with accuracy and precision. Identify and quantify causes and effects of uncertainties in measured data. Record.

Accuracy, Precision, and Security

Accuracy, Precision, and Security

Accuracy, Precision & Significant Analysis Figures ......2017/10/29  · Accuracy • Accuracy = the extent to which a measured value agrees with a standard value Accuracy of a device

Accuracy, Precision & Significant Analysis Figures ......2017/10/29  · Accuracy • Accuracy = the extent to which a measured value agrees with a standard value Accuracy of a device

ROUNDOFF AND TRUNCATION ERRORS. Accuracy and Precision Accuracy refers to how closely a computed or measured value agrees with the true value, while precision.

ROUNDOFF AND TRUNCATION ERRORS. Accuracy and Precision Accuracy refers to how closely a computed or measured value agrees with the true value, while precision.

Measurement and Significant Figures. Precision and Accuracy What is the difference between precision and accuracy in chemical measurements? Accuracy refers.

Measurement and Significant Figures. Precision and Accuracy What is the difference between precision and accuracy in chemical measurements? Accuracy refers.

MULTIPLE DEM MEASURED ACCURACY ABSTRACT - asprs

MULTIPLE DEM MEASURED ACCURACY ABSTRACT - asprs

1.07 Accuracy and Precision

1.07 Accuracy and Precision

Precision Workholding Technology High Precision Air Chucks · **Chuck accuracy is defined as the total indicator reading (maximum radial and lateral runout) of a master gage measured

Precision Workholding Technology High Precision Air Chucks · **Chuck accuracy is defined as the total indicator reading (maximum radial and lateral runout) of a master gage measured

Accuracy vs Precision

Accuracy vs Precision

Accuracy vs. Precision: Understanding Potential Errors ... · Accuracy vs. Precision: Understanding Potential Errors from Radiocarbon ... the half-life model ... Accuracy vs. Precision:

Accuracy vs. Precision: Understanding Potential Errors ... · Accuracy vs. Precision: Understanding Potential Errors from Radiocarbon ... the half-life model ... Accuracy vs. Precision:

DIFFERENTIATE: ACCURACY AND PRECISION

DIFFERENTIATE: ACCURACY AND PRECISION

Standards of Measurements Chapter 1.2. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured.

Standards of Measurements Chapter 1.2. Accuracy and Precision Accuracy – how close a measured value is to the actual value Precision – how close the measured.