1. MEASUREMENT

2. Chapter One: Measurement
1.1 Measurements
1.2 Time and Distance
1.3 Converting Measurements
1.4 Working with Measurements

3. 1.4 Working with Measurements
Accuracy is how close a measurement is to the accepted, true value.
Precision describes how close together repeated measurements or events are to one another.

4. 1.4 Working with Measurements
In the real world it is impossible for everyone to arrive at the exact same true measurement as everyone else.
Find the length of the
object in centimeters.
How many digits does your answer have?

5. 1.4 Working with Measurements
Digits that are always significant:
Non-zero digits.
Zeroes between two significant digits.
All final zeroes to the right of a decimal point.
Digits that are never significant:
Leading zeroes to the right of a decimal point. (0.002 cm has only one significant digit.)
Final zeroes in a number that does not have a decimal point.

6. What is area of 8.5 in. x 11.0 in. paper? Looking for: Given:
Solving Problems
What is area of 8.5 in. x 11.0 in. paper?
Looking for:
…area of the paper
Given:
… width = 8.5 in; length = 11.0 in
Relationship:
Area = W x L
Solution:
8.5 in x 11.0 in = 93.5 in2
# Sig. fig = 94 in2

7. 1.4 Working with Measurements
Using the bow and arrow analogy explain how it is possible to be precise but inaccurate with a stopwatch, ruler or other tool.

8. 1.4 Resolution
Resolution refers to the smallest interval that can be measured.
You can think of resolution as the “sharpness” of a measurement.

9. 1.4 Significant differences
In everyday conversation, “same” means two numbers that are the same exactly, like 2.56 and 2.56.
When comparing scientific results “same” means “not significantly different”.
Significant differences are differences that are MUCH larger than the estimated error in the results.

10. 1.4 Error and significance
How can you tell if two results are the same when both contain error (uncertainty)?
When we estimate error in a data set, we will assume the average is the exact value.
If the difference in the averages is at least three times larger than the average error, we say the difference is “significant”.

11. 1.4 Error
How you can you tell if two results are the same when both contain error.
Calculate error
Average error
Compare average error

12. Is there a significant difference in data? Looking for: Given:
Solving Problems
Is there a significant difference in data?
Looking for:
Significant difference between two data sets
Given:
Table of data
Relationships:
Estimate error, Average error, 3X average error
Solution:
Math answer: in2
Determine # of significant figures = 94 in2