1 / 15

150 likes | 275 Views

Significant Figures and working with measurements. Science 10 G.Burgess Feb.2007. What is a Significant Figure?. A number that demonstrates the precision of a measuring tool. Rules for Measuring significantly. Write out all digits shown by the markings on the measuring tool

Download Presentation
## Significant Figures and working with measurements

**An Image/Link below is provided (as is) to download presentation**
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.
Content is provided to you AS IS for your information and personal use only.
Download presentation by click this link.
While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

**Significant Figuresand working with measurements**Science 10 G.Burgess Feb.2007.**What is a Significant Figure?**• A number that demonstrates the precision of a measuring tool.**Rules for Measuring significantly**• Write out all digits shown by the markings on the measuring tool • Make a guessed digit for the space between the markings • If you are using a mm ruler, you guess a digit for the space between the mm markings.**Recognizing Significant Digits in pre-measured numbers**Rules: • All digits 1-9 are always significant. IE. The number 234 has two S.F.’s. The number 7344.6 has 5 S.F.’s. • Zeros to the left of non-zero digits are not significant. IE. The number 0078 has 2 S.F.’s. The number 022 has 2 S.F.’s.**Recognizing Significant Digits in pre-measured numbers**• Zeros to the right of a non-zero digit are significant only when a DECIMAL is present. IE. The number 7000 only has 1 S.F. because there is not a decimal in the number. The number 70.00 has 4 S.F.’s because there is a decimal. • Zeros between non-zero digits are significant. IE. The number 807 has 3 S.F.’s. The number 70.006 has 5 S.F.’s**Rounding numbers**• Round down all digits ending with 4 or less. • Round up all digits that are 6 or more. • If the digit is a 5; • If the digit before is odd, round up • If the digit before is even, round down.**Practice Problems**• Round the following to 3 Sig. Fig.’s • 0.9973 • 0.01955 • 6.070 • 809.2 • 875.54 • 0.0019754 • 201.59 • 29.27 • 20.52 • 687.59300 • Answers • 0.997 • 0.0196 • 6.07 • 809 • 876 • 0.00198 • 202 • 29.3 • 20.5 • 688**Scientific Notation**• The short hand method for writing very large or very small numbers and showing numeric significance • All notation numbers have a non-zero digit followed by a decimal and other significant digits. • IE. 87.99 rounded to 2SF would be 8.8 X 102 • Check out next slide to find out how.**How to convert to Scientific Notation**• Converting 0.97580 to sci.notation. • Write first non-zero digit. In this case it is the digit 9 • Put a decimal after the 9 • Write out all other digits • Write X 10 • Give the 10 an exponent that represents the number of places the decimal was moved. • **minus means decimal was moved to the left • **plus means the decimal was moved to the right. Example: 9 9. 9.7580 9.7580 X 10 9.7580 X 10-1**Using Scientific Notation to show significance**• The only digits that appear in a sci.notation number are the significant ones. IE. • 79,954.094 rounded two significant figures would be; • 80,000 • Using scientific notation the number would be; • 8.0 X 104**Practice Problems**• Convert the following numbers to scientific notations having 3 sig figs. • 0.000207 • 98.256 • 999.999 • 5467.3 • 100809.2 • Answers • 2.07 X 10-4 • 9.82 X 101 • 1.00 X 103 • 5.47 X 103 • 1.00 X 106**Multiplying and Dividing with significant figures**• Your answer must be rounded to the same number of significant digits as the number with the least number of significant digits. 75 = 2 SF’s X 1.256 = 4 SF’s 94.200 = 5 SF’s **Answer must be rounded to 2 SF’s. Answer = 94**Practice Problems**• Complete the following using Sig figs. • 6.25 X 0.3 =___ • 78 X 0.345 =___ • 2 x 16 = ___ • 25.03 5.33 = ___ • 0.09465 0.00356 = ___ • 2 • 27 • 30 • 4.70 • 26.6**Adding and Subtracting with Significant Figures**• Your answer must have the same number of place values as the number with the least. 18.509 = 3 SF after Decimal +96.5 = 1 SF after Decimal 115.009 = 3 SF after Decimal **Our answer must have no more than 1 place after the decimal. Answer is 115.0**Practice Problems**• Complete the following using Sig figs. • 13.05 + 6 = ___ • 120 + 56.5 =___ • 1209.9 + .1 = ___ • 0.98 – 0.0567 = ___ • 0.16458 - .1307 = ___ • Answers • 19 • 176 • 1210.0 • 0.92 • 0.0339

More Related