2. Uncertainty in Measurement
Precision: how close together the measurements are to one another
Accuracy: How close to the true value

3. Significant Figures What’s Significant?
-Sig. Figs tell the reader how precise the measurements were taken
What’s Significant?
All non-zero digits (1,2,3,etc.)
2. All Zeros appearing in between non-zero digits (101,102, etc.)
3. Zeros that appear in front of non-zero digits are NOT significant
Example: 
7x 10-6
(only one sig fig)

4. Sig fig rules
4. Zeros at the end of a number and RIGHT of the decimal place ARE significant
Example:
(3 sig figs)
5. Zeros to the right of a number are not significant, Unless there is a decimal point
Ex. 5200
2 sig figs
however: 5200.
Now has 4 sig figs

5. How many significant figures in each
314________ ________
______ ________
500.0_______ ______
_______ x 105______

6. 1. 42 ______________ 2. 4003_____________
More Examples
Indicate the number of significant figures
______________ _____________
____________ _____________
______________ _____________
___________ ____________
_____________ _____________
_________ ______________
__________ __________
____________ _________
x 104__________ x 10-6_________

7. Significant Figures in Calculations
Multiplication/Division
------The answer can have no more significant figures than there and in the measurement with the smallest number of Sig. Figs.
Ex x 3.0 = 51.6
(3) (2)
Therefore have to round to 2 sig figs
Solve and answer with the correct number of sig figs
x 0.3__________ / 10____________
3. 162/ 10.__________ / 10.0___________
x 2.00_________ x 102/189__________

8. Addition / Subtraction
Answer can have no more decimal places than there are in the smallest measurements. (# To the right of the decimal) Ex
In addition / subtraction we can gain or lose sig. Figs.
= 100
(2) (2) (1)