Slide 1 of 48 Measurements and Their Uncertainty 3.1 3.1

Slide 1 of 48

Measurements and Their Uncertainty 3.1

3.1

© Copyright Pearson Prentice Hall

Measurements and Their Uncertainty

>

Slide 2 of 48

Significant Figures in Calculations

Significant Figures in Calculations

How does the precision of a calculated answer compare to the precision of the measurements used to obtain it?

3.1

Slide 3 of 48



> Significant Figures in Calculations

In general, a calculated answer cannot be more precise than the least precise measurement from which it was calculated.

The calculated value must be rounded to make it consistent with the measurements from which it was calculated.

3.1



>

Slide 4 of 48

3.1 Significant Figures in Calculations

Rounding

To round a number, you must first decide how many significant figures your answer should have. The answer depends on the given measurements and on the mathematical process used to arrive at the answer.


SAMPLE PROBLEM

Slide 5 of 48

3.1


SAMPLE PROBLEM

Slide 6 of 48

3.1


Slide 7 of 48

Practice Problems

.

for Sample Problem 3.1

Write down your answers.



>

Slide 8 of 48


Addition and Subtraction

The answer to an addition or subtraction calculation should be rounded to the same number of decimal places (not digits) as the measurement with the least number of decimal places.


SAMPLE PROBLEM

Slide 9 of 48

3.2


SAMPLE PROBLEM

Slide 10 of 48

12.52 349.0 8.24 369.76

Final Answer 369.8 meters


Slide 11 of 48

Practice Problems for Sample Problem 3.2

Write down your answers and round toThe correct number of SF’s..



>

Slide 12 of 48


Multiplication and Division

• In calculations involving multiplication and division, you need to round the answer to the same number of significant figures as the measurement with the least number of significant figures.

• The position of the decimal point has nothing to do with the rounding process when multiplying and dividing measurements.


SAMPLE PROBLEM

Slide 13 of 48

3.3


SAMPLE PROBLEM

Slide 14 of 48

3.3


Slide 15 of 48

Practice Problems for Sample Problem 3.3

Write down your answer with the correctNumber of SF’s.


Slide 16 of 48

Section Quiz

-or-Continue to: Launch:

Assess students’ understanding of the concepts in Section 3.1.

Section Assessment

Write down your answers.


Slide 17 of 48

3.1 Section Quiz

1. In which of the following expressions is the number on the left NOT equal to the number on the right?

a. 0.00456 10–8 = 4.56 10–11

b. 454 10–8 = 4.54 10–6

c. 842.6 104 = 8.426 106

d. 0.00452 106 = 4.52 109


Slide 18 of 48

3.1 Section Quiz

2. Which set of measurements of a 2.00-g standard is the most precise?

a. 2.00 g, 2.01 g, 1.98 g

b. 2.10 g, 2.00 g, 2.20 g

c. 2.02 g, 2.03 g, 2.04 g

d. 1.50 g, 2.00 g, 2.50 g


Slide 19 of 48

3. A student reports the volume of a liquid as 0.0130 L. How many significant figures are in this measurement?

a. 2

b. 3

c. 4

d. 5

3.1 Section Quiz

END OF SHOW

Documents

Slide 1 of 48 Measurements and Their Uncertainty 3.1 3.1