Uncertainty
What is the uncertainty in the following number:
3.12 dm
+/- 0.01 dm
What is the proper format for scientific notation?
A x 10a
A - is a decimal number between 1 and 10
a - a positive or negative integer
What is a significant figure?
Digits of a number with some degree of certainty
Name the two aspects of uncertainty
Precision and accuracy
What numbers do not have uncertainty?
Exact numbers
ex. 10 frisbees, 1 dog, a dozen donuts etc..
What is the scientific notation for the following number:
0.000789 mm
7.89 x 10-4 mm
How many significant figures are in 0.00289001 nm?
6 sf 0.00289001 nm
Define precision
agreement among repeated measurements
What do/does the uncertainty of measurement(s) represent?
the reliability of measurements
Express 9.654 x 10^5 m in decimal form
965400 m
Exact numbers contain how many significant figures?
Infinite
Define accuracy
agreement of a measurement with the true or accepted value
Calculate the following with correct significant figures: 4.90 X 5.917 = 29.0
28.9933 -> 29.0 (three sig figs)
Can a measurement be both accurate and precise?
Yes, a repeated measurement close to the true/accepted value is both accurate and precise
Calculate the following with correct significant figures: 7.8 + 9.663 = ?
17.463 -> 17.5 (three sf)
Explain how measurements can be precise, but not accurate.
Measurements with the same repeated results far away from the true/accepted value are precise but not accurate.