Scientific Notation Notes

  • Scientific Notation
    • Measurement
      • Two parts
        • Number
        • Unit
      • We work with really large and small numbers
  • Scientific Notation
    • Coefficient (6.022) followed by a base (10) followed by an exponent (23)
    • If the exponent is positive then the number is greater than one
    • If it is negative then it is a decimal
    • The coefficient must be between 1 and 9, inclusive
    • Sometimes in science we use spaces instead of commas
    • After every third number
  • Accuracy vs Precision
    • Accuracy is how close a measurement is to its true value
    • Precision is the ability to repeat a measurement
    • In lab, she wants us to be precise
    • If you are precise then that means it is most likely the fault of the instrument
    • Being precise is extremely important in lab
    • Accepted value is the experimentally proven true value
    • The boiling point of water is 100 C
    • The reference value
    • The book value
    • It is consistent and it is always true
    • Experimental value is the value that you get in lab
    • That is when a person runs a lab and they get a value for something
    • Percent Error is the 1) x 100% (A-E)/(A)
  • Percent Error Problem
    • Lisa weighed a copper cylinder to be 46.83g. The correct mass of the cylidner is 48.32 g. Calculate the percent error.
    • The percent error in this case would be roughly 3.08%
  • Significant Figures
    • Reporting a measurement
    • Significant figures
    • When we take a measurement, we always take it to the precision of the instrument plus one more
    • For a ruler, we would use it to the second decimal place
    • With the thermometers in the lab, we would have to measure to the first decimal place
    • Significant Figures include all of the certain digits in the measurement plus the one that is uncertain.
    • Rules for significant figures
    • The answer can only be as accurate as the device that took the measurement
    • All nonzero digits are significant
    • Captive Zeros are significant (0s that have numbers around it (it is in the middle))
    • 20.55 would be 4 and 200.05 would be 5
    • Leading 0s are not significant
    • 0.00253 would be 3 and 0.0305 would be 3
    • Trailing 0s are significant when there is a decimal point
    • 200.00 would have 5, 40.50 would have 4, 3400 would have 2, and 0.050600 would have 5
    • Sometimes you would have to use scientific notation to get the correct number of significant figures
    • Exact numbers have an infinite amount of significant figures
    • conversion factors
    • constants
    • number of desks in the row would be exactly 5 and so it would have in infinite amount of significant figures
1)
|accepted value - experimental value|)/(accepted value

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