PASCO ME-9849 Significant Figures Set - Manual (Page 10)

Significant Figures Set Length Measurements with the True Meter Stick
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This would also be an appropriate time to discuss the role of zeroes in significant figures.
Place Holder Rule or Leading Zeroes
Zeroes that serve as placeholders are NOT significant.
Example: .003 g contains only one significant figure, the "3."
Right-Right Rule or Trailing Zeroes
Zeros to the right of the decimal AND to the right of the last significant figure are significant.
Example: 1.400 m contains four significant figures.
Decimal Rule (Used for Whole Numbers)
If a decimal is NOT included for a whole number, rightmost zeroes are NOT significant.
Example: 2300 km contains two significant figures.
If a decimal is included for a whole number, rightmost zeroes are significant.
Example: 2300. km contains four significant figures.
Note: Sometimes a line is written above a zero to identify that it is significant.
Example: 2300 km contains three significant figures.
Sandwich Rule
Zeroes in between other significant figures are significant.
Example: 20.03 g contains four significant figures.
Questions:
1. In this activity, a meter stick was used to make measurements. Make a list of techniques
necessary to insure optimum precision when using a meter stick.
Sample values: .145 m .144 m .146 m .144 m
2. How many digits can you read with certainty?
3. Which digit is uncertain?
4. For the following measurements underline the digits that are known with certainty and circle
the digits that are estimated.
4.35 m .009340 g 3400 km 1.38 x 10
3
m/s