1-3 Scientific Notation or Exponential Notation (Section 2. 1, p

To write a number in scientific notation, move the decimal to create a number between 1 and 10, followed by an exponent that would move the decimal to give the original number. For example, 1035 = 1.035 x 103 and 0.00306 = 3.06 x 10-3.

1-4 Dimensional Analysis (Section 2.6, p. 28-33) Dimensional analysis uses the idea that units can cancel, just like numbers, and anything divided by itself = 1. 2 • 2 = 22 x • x = x2 cm • cm = cm2 2/2 = 1 x/x = 1 cm/cm = 1

Conversion Factors 1 ft = 12 inches 5 ft 12 in = 60 in 1 ft A string of conversions can be used to find # sec. in one year : 1 year 365 days 24 hours 60 min 60 sec = 31,536,000 sec 1 year 1 day 1 hour 1 min  

Converting both numerator and denominator is possible, as long as the units to be canceled are placed diagonally. Example: How fast, in miles/hour, is the speed of light (3.00 x 108 m/s)? You need to convert meters to miles and seconds to hours!!!! What fun 

Note: Always write the units vertically, m not m/s s 3.00 x 108 m 60 sec 60 min 1 km 0.62 miles = 6.70 x 108 mi s 1 min 1 hour 1000 m 1 km hr  

1-5 Accuracy –vs- Precision Accuracy refers to “how close a particular value is to the true value”, while precision refers to “how close several measurements of the same quantity are to each other.” For example, three students are attempting to measure the mass of a metal cylinder using a triple beam balance. Each student weighs the cylinder 3 times. The accepted “true” mass of the cylinder is 3.00 g. Below are the results:

Trial # Student #1 Student #2 Student #3 3.01 g 2.50 g 4.00 g 2 3.00 g 4.01 g 3 2.99 g 3.50 g 3.99 g Average Comment on the precision and accuracy of the measurements recorded by each student: Student #1 Student #2 Student #3 Student #1 a, p Student #2 no a, no p Illusion of accuracy Meas #3 no a, but p

Are the groups accurate? Precise? Can there be accuracy for a group without precision?