1. Measurements Every measurements has UNITS
Every measurement has uncertainty

2. Accuracy and precision
How close a measurement is to the accepted value
How close a series of measurements are close to one another. The closer the measurements are to one another, the more precise it is.

3. Accuracy and Precision

4. Significant figures
are used to indicate the precision of a measured number or sets of numbers
Measurements are made one place beyond where the measuring device is marked. In any measurement, the digit furthest to the right is estimated
For example, a ruler marked to the nearest tenth of a centimeter can be read to the hundredths place by estimating how far between the lines the measurement falls.

5. Estimate +0.1/-0.1 By estimating the last digit, our measurements are not precise, they have an estimated error of +,-0.1 When you are measuring small quantities, you need to use equipment that is more precise to avoid a greater potential for error
2.35cm

6. Sig Fig Rules ALL NON ZERO DIGITS ARE SIGNIFICANT
TRAILING ZEROS ARE NOT SIGNIFICANT
30,000m x 104 m sig fig
300m
30m 3m

7. Sig Fig Rules SANDWICHED ZEROS ARE SIGNIFICANT 303 yrs 3 sig figs
3104 lbs
5080 g

8. Sig Fig Rules LEADING ZEROS ARE NOT SIGNIFICANT
0.008m x sig fig
0.3cm cm mm cm

9. Calculations and reporting the correct number of sig figs
ADDITION AND SUBSTRACTION
Look at the decimal places and your report your answer with the least
35.23g g
58.33g → 58.3g
Significant to the 0.1 place

10. Calculations and reporting the correct number of sig figs
MULTIPLICATION AND DIVISION
Report you answer with the least amount of significant digits used in your calculation
0.2451g x 3.51g x g=
Your answer can only be reported with 3 sig figs → g

11. Practice How many sig figs are in the following numbers: 9.03 x 103 mm
5051ft
0.0033
48,600 gal

12. Practice
Write the answer in scientific notation and with the correct number of sig figs:
2.70 g x 0.050g x 8.09g =
8540 / =
100 x 340=
50.0 / 80=