1. Good Afternoon! Today is Tuesday, September 15, 2015 HW Due: None Do-Now: Please write three sentences describing what you think “significant figures” means. If you have not heard of it before, take a guess as to what it might mean.

2. Significant Figures Helps to show how precise a numerical measurement is There are a few rules of thumb when determining the number of significant figures in a number

3. Significant Figures 1.Non-zero numbers and zeros between non-zero numbers are significant. 723 504 400,503

4. Significant Figures 2. Leading zeros, or zeros before non-zero numbers are not significant. 0.05 0.0000043 0.000507

5. Significant Figures 3. Trailing zeros, or zeros after the last not-zero number can be tricky. a. If there is a decimal, the trailing zeros are significant. b. If there is not a decimal, the trailing zeros are not significant. 2,000 0.00520 600.

6. Practice with Significant Figures 1.4,856 2.0.0000534 3.1,000,000 4. 5.09 5.3,450 6.0.04567 7.4,040 8.123.980

7. Homework Complete “Determining Significant Figures #1-14” for tomorrow Be sure to turn in Syllabus Agreements and Lab Safety Contracts