Pt1420 Unit 6 Assignment

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Pages: 3

Hi Lee, Unfortunately, I had to leave to go to a wedding before you came back to the office for me to give you instructions. However, I have left a note for you, which should answer any questions you have. Every time you take a measurement, there is always some degree of uncertainty. It is important to record only the numbers that are significant. These significant figures refer to the numbers that the person who is measuring deems to be right without losing the accuracy of the measurement.
I know sometimes we use the words “accuracy” and “precision” interchangeably, but when it comes to science, they are different. Accuracy is how closely your measured amount is to the true amount of an item and precision is how well individually measured amounts agree
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The first number has three sig-figs and the second number has four. I was able to determine this by following three rules: 1) All non-zero numbers and zeros between two non-zero numbers are significant. 2) If a decimal place is present, trailing zeros are significant. 3) Leading zeros in a number are not significant.
You may be wondering what the zeros that are not significant mean. The four zeros to the right of the decimal point in 0.0000420 are placeholders and are not significant. The zeros after the four are not significant as well because there is no decimal point.
Another important concept to understand is scientific notation. Scientific notation allows us to write numbers in a way that is easier to understand. 0.0000420 becomes 4.20 x 10−5 and 1004000 is 1.004 x 106 .The exponent is found by counting the number of places you must move the decimal to expand the number. A positive exponent means you will move the decimal place to the right when going from scientific notation to expanded form and a negative exponent means you will move it to the left. See how by converting the numbers to scientific notation it is also easier to see how many sig figs are