1. QUESTION:
Which of the following has the fewest number of significant figures? A mg, B mL, C g D x10-3 m
If number is written in scientific notation, all digits in the coefficient are significant.
If number is not written in scientific notation, first significant digit is the first nonzero digit.
>>>If number has a decimal point, all digits after the first nonzero digit are significant
>>>if there is no decimal point, trailing zeros may or may not be significant --- assume that only digits up the last nonzero digit are significant.
SCRIPT
Which of the following has the fewest number of significant figures?
…Ten point five zero milligrams
…Twenty thousand seven hundred milliliters
…zero point zero zero three one zero zero grams
…or one point five zero zero times ten to the negative third power
PAUSE 3 seconds.
To answer this question, let’s count the number of significant figures for each of the choices given.
Let’s start with choice D, which is written in scientific notation…
BOX CHOICE D
CLICK
A number is written in scientific notation if it is written as a number between one and ten, which is called the coefficient HIGHLIGHT
Times a power of ten
HIGHLIGHT 10-3
If a number is written in scientific notation, then all the digits in the coefficient are significant.
HIGHLIGHT the word “coefficient”
HIGHLIGHT 1.500
Therefore, there are four significant digits in choice D….. One, five, zero, and zero
CALLOUT “4 s.f.” next to choice D
Let’s take a look at the other choices, which are not written in scientific notation.
In these cases, the first significant digit is the first nonzero digit --- that is… the leftmost nonzero digit.
For choice A, the first significant digit is one ---- HIGHLIGHT 1
For choice B, the first significant digit is two ---- HIGHLIGHT 2
For choice C, the first significant digit is three --- HIGHLIGHT 3
Now, if the number has a decimal point, as in choices A and C, then all digits to the right of the first significant digit are also significant.
HIGHLIGHT “If number has decimal point…. “ on slide
So, in choice A, the numbers zero, five, and zero are also significant.
HIGHLIGHT 0, 5, and 0 as they are called out)
Choice A has four significant figures…. CALLOUT “4 s.f.” next to choice A
In choice C, the numbers one, zero, and zero are significant…
So, choice C has four significant figures…. CALLOUT “4 s.f.” next to choice C
Finally, let’s take a look at choice B, which is not in scientific notation and does not have a decimal point.
HIGHLIGHT “if there is no decimal point….” in slide
The rule in this case is that trailing zeros may.. Or may not be significant.
HIGHLIGHT last two zeros in
It is customary to assume the worse --- that is… that they’re not significant.
Therefore, if unless we are given information to the contrary, only two, zero, and seven are significant in choice B.
There are 3 significant figures in choice B.
CALLOUT “3 s.f.” next to choice B.
The correct answer is B. It has only three significant figures… the other choices have four significant figures.

2. Video ID: 1A-2-1 © 2008, Project VALUE (Video Assessment Library for Undergraduate Education), Department of Physical Sciences Nicholls State University Author: Glenn V. Lo Narrator: Glenn V. Lo Funded by Louisiana Board of Regents Contract No. LA-DL-SELECT-13-07/08