1. Definitions and Examples
Accuracy
Closeness of a measurement to the accepted value
Precision
Reproducibility of a measurement
Physics 104

2. Significant Digits All measured digits plus one estimated digit
Read the smallest division on the instrument and then estimate one more digit 3 3 2
3.21 has ___ significant digits. The ___ and ___ are measured and the ___ is estimated.
Eight and ¼ meter long string should be reported as ____ m or ____ m. 1
8.2
8.3
Physics 104

3. 1 Y 3 5 Review In a measurement, how many digits are estimated?
Is the estimated digit significant?
A measurement 2.45 m has ___ significant digits.
The ___ is the estimated digit. 1 Y 3 5
Physics 104

4. Convert 2.54 m to … km Mm dm cm mm μm 0.00254 km 0.00000254 Mm 25.4 dm
In each, the ___ and the ___ are measured and the ___ is estimated.
The purpose of the zeros is to act as decimal place holders. 4
Physics 104

5. 8600 m = 8.60 x 103 m A zero can be a measured digit.
A zero can be an estimated digit.
Zeros are not significant when they are place holders only.
Significant digits examples
83000 km g s
56.08 m/s
8.3 x 103 cm
8.30 x103 cm
g/cm3
Cover up the zeros. Does the magnitude of the number change?
Do zeros disappear when in scientific notation?
To show that a place holding zero is significant, put a bar over the zero.
8600 m = 8.60 x 103 m
Physics 104

6. Problem Set #1
1.080 x 10-4 kg
m/s s
6.0 x 10-4 m3
Physics 104