1. Warm-Up: To be turned in
How long (in cm) is this line?
What is the volume (in mL) of the liquid?

2. Using Scientific Measurements
Sig Figs and Scientific Notation

3. Accuracy vs. Precision
Accuracy- how close the measurements are to the accepted value
Precision- how close the measurements are to each other

4. Sig Figs
The digits in a measured number that indicate the measuring equipment’s degree of precision.
All numbers in a measurement are known with certainty, except for the last number

5. Determining the Number of Sig Figs
All non-zeros are always significant
Leading zeros are never significant
Ex: has 2 sig figs
“sandwiched” zeros are always significant
has 5 sig figs
Trailing zeros are significant only if there is a decimal
2000 has 1 sig fig
2000. has 4 sig figs

6. Practice
Put the following numbers in order from the fewest sig figs to most sig figs:

7. Solving problems Using Sig Figs
Adding/ subtracting- answer will have the same number of digits as the number with the fewest decimal points
Ex: = 9.08  9.1
Multiplying/ dividing- answer will have the same number of digits as the number with the fewest sig figs
Ex: 2.6 x 3.14 =  8.2

8. Practice
= x 2.56=

9. Scientific Notation
Shorthand for writing really large and really small numbers
M x 10n format
M is a number greater than 1, but less than 10
N is a whole number whose value is based on how many places the decimal is moved to the left or right
Ex: 90,000= 9 x = 9 x 10-4

10. Practice
Put the following in scientific notation:
Put the following numbers in standard notation:
2.5 x 106
1.36 x 10-4

11. Solving Problems Using Scientific Notation
Addition/ subtraction- can only be done if exponents are the same
Add M values, but leave exponent the same
Ex: 3.6x x104 = 5.4x104
Multiplication/ division- multiply M values, add (if multiplying) or subtract (if dividing) exponents
Ex: 1.2x103 x 2.0x107 = 2.4x1010

12. Practice
2.5 x 106 – 1.0 x 106 = 2.5 x 106 = 2.0 x 102