1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Significant Figures concept

  1. Sep 1, 2005 #1
    I don't really get the concept of significant figures. Anyone can help me out?
    1200 X 23.4
    What is that in significant figures?
  2. jcsd
  3. Sep 2, 2005 #2
    *Significant figures = "sigfigs"
    Remember that products will have as many sigfigs as the least accurate multiplier.
    Here, in your case, 1200 [itex] \Rightarrow [/itex] 2 sigfigs, and 23.4 [itex] \Rightarrow [/itex] 3 sigfigs.

    *Therefore, the product will have two sigfigs, represented as [itex] 28000 = 2.8 \cdot 10^4 [/itex]

    ->Just remember the sigfigs product rule here :wink:
  4. Sep 2, 2005 #3
    I always hated those when I was first learning them. Here are the basic rules.

    -All digits except zeros at the beginning of the number are significant.
    i.e 9.12 (3) 0.912 (3) 0.00000912 (3)

    -Terminal zeros @ right of decimal point are significant.
    i.e 912.0 has four.

    Multiplication and division;

    Final answer has the same amount of significant figures as the number with the least sig fig in original problem.

    i.e 34.987 x 54.2 = 1896.3

    Addition and subtraction;

    Final answer has the same number of sig fig as the number with the least number of decimal places.
    i.e 12.9875 + 1.23 = 14.22

    I think the best way to explain it is, you answer can only be as accurate as the least accurate answer. If that makes sense.

    If you still don't get it, I have another way to explain but it's as long, if not longer than this. I don't really want to type that out yet. Haha.

    Hope this helps.
  5. Sep 2, 2005 #4
    Hmm, I always liked sigfigs, never hated learning them.. :smile:
    Last edited: Sep 2, 2005
  6. Sep 2, 2005 #5


    User Avatar
    Science Advisor
    Homework Helper

    first term has two sig figs, the second has three, your final product should have two sig figs.
  7. Sep 2, 2005 #6
    Ok, not really hated. But they are easy to get confused on. So as I was learning them I can't say I liked them. :tongue2:

    But after the first few minutes I liked them. Most of the class was still having problems with them by the end though.
  8. Sep 6, 2005 #7
    The concept is very simple, but it is surprisingly easy to make a mistake when working with sigfigs.
  9. Sep 6, 2005 #8
    *Mostly I just double-check my work to ensure proper use of sigfigs :cool:
    However, the stupid mistakes I do make :shy:, are just silly arithmetic errors (working under duress!), usually (+) sometimes (-). Though when working under pressure/duress...double-checking isn't always convenient :rolleyes:
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Significant Figures concept
  1. Mole Concept (Replies: 1)

  2. The concept of mole (Replies: 4)

  3. Significant figures (Replies: 6)