1. Significant Digits

2. What are significant digits?
So that we don’t have endless numbers behind a decimal point, scientists have agreed on some rules to determine which numbers in a measurement are really important
Significant digits are the digits of a number that really mean something

3. Rules for significant digits:
Non-zero digits in a measurement are always significant.
For example: if a car odometer measures 7.2 miles, then there are TWO significant digits
(the “7” and the “2”)

4. Rules for significant digits (contd.)
Zeros between two significant digits in a measurement are significant.
For example: The number has 4 significant digits.

5. Rules for significant digits (contd.)
All final zeros to the right of a decimal point are significant.
If there is no decimal point, final zeros are NOT significant.
So, “1.000” would have 4 sig. digits, but “10” would only have 1 sig. digit.

6. Rules for significant digits (contd.)
Zeros that exist only to put the decimal point in the right place are NOT significant.
So if we had “ kilometers”, it would only have 1 sig. digit.

7. How many sig. digits are there in . . .
36.33 minutes?
Answer: 4 significant digits

8. How many significant figures are there in . . .
0.0074?
Answer: 2
0.010 kilograms?

9. “Math for Science”

10. Accuracy How close a measurement comes to the actual or true value
“Correctness”

11. Precision
A measure of how close a series of measurements are to one another
“Repeatable”

13. Error
Error: The difference between the accepted value and the value you measured in the lab

14. % Error Calculation (Accepted – Experimental)

15. Types of Observations Quantitative = number
Qualitative = like (description)
Examples: 171cm or tall
2.35kg or heavy OC or hot

16. Scientific Notation (x 10) means “time 10 to the __ power)
Move Decimal Point (by # of spaces)
If positive, makes number bigger (right)
If negative, makes number smaller (left)
Ex: 1 x 102 or x 10-2
Ex: or