1 / 16

Review of Essential Skills:

Review of Essential Skills:. SI Units, Scientific Notation, Significant Figures & Rounding. SI Units. Standard Unit: Metric is usually the preferred unit in science. Metric referred to as “S.I.” (System Internationale ) Also known as MKS system M etres : Standard unit for distance

magda
Download Presentation

Review of Essential Skills:

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

Presentation Transcript

  1. Review of Essential Skills: SI Units, Scientific Notation, Significant Figures & Rounding

  2. SI Units • Standard Unit: Metric is usually the preferred unit in science. • Metric referred to as “S.I.” (System Internationale) • Also known as MKS system • Metres: Standard unit for distance • Kilograms: Standard unit for mass • Seconds:Stanard unit for time • Some examples: Speed (m/s), Volume (m3)

  3. Scientific Notation • Often in Physics, calculations require the usage of large figures, scientific notation makes these calculations easier. • Some examples: • 37010000 m = 3.701 x 107 m • 0.00003152 s = 3.152 x 10-5 s Decimal moved left? Positive Exponent Decimal moved right? Negative Exponent

  4. SN Recipe • Place a decimal to get a number between 1 and 10. • Multiply by 10. • Add a power/exponent to the 10 based on the number of times you moved the decimal.

  5. Eg.1: Convert each number below to scientific notation. • Eg.2: Convert each number to real notation. a) 0.0673 km b) 350 000 145 s = 0.0673 = 350 000 145 = 6.73 x 10-2km = 3.50000145 x 108s a) 4.5 x 103m b) 2.3456 x 10-7s = 23456 = 45 0.000000 00 = 0.000 000 23456 s = 4 500 m

  6. Significant Figures (“Sig Figs”) • Values that are significant to a measurement • Gives certainty to any measure. • Guidelines • Count from left to right, beginning with the first non-zero digit.

  7. 2. Zeros at beginning are never significant.

  8. 3. All non-zero digits in a number are significant.

  9. 4. Zeros between digits are significant.

  10. 5. Zeros at the end of a number with a decimal point are significant.

  11. 6. Zeros at the end of a number without a decimal are not significant.

  12. 7. All digits in the coefficient of a number written in scientific notation are significant.

  13. Significant Figures (“Sig Figs”) • Values that are significant to a measurement. • Leading / trailing zeros are typically placeholders. • Eg.3: State the number of sig figs in each case. 2 Last 3 zeros are placeholders 5 Last 2 zeros are placeholders ~ 4 Tilde (~) indicates last significant figure Numbers recorded AFTER decimal place wouldn’t be recorded unless significant 4 Leading zeros not significant, last two digits are part of the measurement 5

  14. Rounding Rules • Very simple set of rules with the exception of numbers terminating in 5 • Rules: • Number terminates in value > 5: Round up • Number terminates in value < 5: Round down • Number terminates in 5: • Round to ensure the rounded value is an even number.

  15. Eg.4: Round to the specific number of sig figs. • Since the last example is terminated by a non-zero number, the “5 rule” does not apply… 5.64 4.63 3.6 3.6 3.6 3.7

  16. Why the “5 rule”? • Automatically rounding up skews data in one direction. Eg.5: Consider the following data set: [1.5, 2.5, 3.5, 4.5] • Original sum: 1.5+2.5+3.5+4.5 = 12 14 [2,3,4,5] [2,2,4,4] 12

More Related