Significant Figures

[ccouge]

i <3 you

u helped me out lots :D

[KimGyunAh]

Singh is King, Khan is Mahan. :p

[WeShallNeverStop]

I love you.

[Mogster27]

And then everything makes sense.

[ZombieTacticalStore]

WOW! The Kilometer part really helped me to see it. Thank you!

[labbeellaavita]

so if im multiplying 6.0kg and 3.0m/s, both numbers have 2 significant figures right? and my answer will be 18 kg m/s ???

[hekje12345]

Finally I found someone explaining why some of these zeroes are not signficant.

[shakilmujeeb]

Really forgot this since my elementary education

[KOcreative8991]

what if it is :

39,010

and

1.5300

[snowpixie15]

THANK YOU GOOD SIR. My teacher sucks at her job.

[superrkoman]

@snowpixie15 me2 what school?

[selectguygl]

heres how i do it:

i dont remember any rules i just imagine this:

If there is a decimal point Present an airplane will come from the Pacific ocean, airplanes can fly through 0's but not any other number so all of the numbers the 'plane' flies through dont count. If the decimal is Absent it comes from the Atlantic and the same rules then apply.

ex: 0.00700 the decimal is present so from the pacific (left) it goes through 3 zeros leaving you with 700 or 3 sig figs... much easier imo

[helloooerinnn]

would 370. and 370.0 have the same number of sig figs?

[shayan894]

@helloooerinnn no friend 370. has 3 sig fig where as 370.0 will have4 sig fig

[Madsupervilian]

@helloooerinnn no 370. = 3 s.f. and 370.0= 4 s.f.

spend time to study youll get it

[CapsRule1]

still dont quite get it...fml

[rilesbriles]

Thank YOU I finally understand now!

[0mgitsthatkidagain]

You sir, are a pro with writing with your mouse and a pro at tutoring

[sharmin801]

YOU are the King Khan.

[TheBlankThought]

oh God. Im still so confused, ive looked up a ton of crap on this, not to mention, seen a bunch of videos, one even including a rap...(no comment)...and still, im cluess. Curse chemistry. i'm unna freaking kill the guy who thought that we need it unless we decide to pursue a career in it.

[TheChasian]

he's getting pretty good at writing with his mouse :P

[DuHabst]

Which program do you used in this video? :)

[virgilio1011]

why is there an echo?

[valdas0]

Sorry but I don't see how is this usefull. We don't even learn them in europe... I think.

[UltraMaXAtAXX]

@valdas0 In chemistry and physics, significant digits are used to maintain how precise a measurement is.

[ihavemonkeysinmybutt]

intense.

[DarkKiss92]

what for is all this stuff? I've graduated high school recently and I have no idea what is it. Is anybody Polish in here who could translate me "significant numbers" into 'polish' version? Or anybody who could answer me what for is it?

[cameronvcope]

@DarkKiss92

The concept of significant figures is for recording the precision of measurements within calculations. Error can quickly compound (especially when multiplying) so its relevant to not imply that a calculation is more precise than the least precise measurement.

[cameronvcope]

has anyone else noticed that if one simply take any number and write it in scientific notation then any 'leading' zeros naturally fall away?

for example .0040400 in scientific notation is 4.0400 e-3

so one would have to deliberately remove the last two zeros or the zero between the 4's - implying that they are significant.

there is really no need to memorize any rules about leading, trailing or sandwiched zeros, if one simply consider how the number would be written in scientific notation.

[cameronvcope]

@Mcalister011

37,000. would be 3.7000 x 10^4

[Mcalister011]

@cameronvcope You are correct. I will remove my previous comment.

[NScott45]

basically, 10.0 is any number between 9.95 and 10.04

[GazaAlley]

ummm anyone know what is 151.208 corrected to 2 significant figures?

[cameronvcope]

@GazaAlley

150

[TheLegendaryOne01]

@ eirpcalc @eirpcalc thanks for explaining engineering notation for me. But to answer your question there is no way for somebody to know that the first zero is a significant figure without resorting to scientific notation or engineering notation. The reason for placing a number like 37000 in scientific notation is to make the number of Sig figs really clear without any doubt. So it would be hard to show a number like that to be three Sig figs instead of the conventional two.

[MetalMonkeyStudios]

yeah i think 37,000 has no significant figures 37,000. has 5 significant figures

[Alderslodge]

@MetalMonkeyStudios

37,000 does have 2 significant figures. With the absence of a decimal, you count from right to left, and the sig figs begin with the first non zero integer.

[MetalMonkeyStudios]

@Alderslodge if im not mistaken 37000 is not a measurement 37000.0 is a measurement. Correct me if im wrong (lol im in the 10th grade i just got these things this year)

[preptimenow]

Sal, you are so easy to fallow. Thanks.

[BamanUTube]

Clear and useful

[SEThatered]

Great explanation.

.

I think it would be helpful if you explained the real-world use of these significant numbers.

Like different tolerances in wood (cm), metal (mm) and concrete (m) measurements.

Or how they can include a possible deviation (f.e. thermal expansion) of measurements.

Thank you.

[hooloovoo1st]

@SEThatered The way I understand it, they mainly exist to AVOID those things. They are intended to be a rough indication of the accuracy of measurements and calculations without having to do the sometimes complicated errors calculations.

[SEThatered]

@hooloovoo1st

Apologise if my comment was not clear.

I study architecture and i know, that "significant numbers" are a must for an architects.

It is no use to measure wood in mm, because it get wet or dry, and because of that twists, bends shrinks or expands significantly.

So the area of interest must be higher than order of mm, and that would be cm (or inch if imperial).

[eirpcalc]

If I'd measured the 37,000 to 3 significant figures, I could write it as 37.0 x 10 [to the third]. Can it be done without resorting to engineering notation, or scientific notation?

[TheLegendaryOne01]

@eirpcalc If you measured something to 37,000 then you only have two sig figs there. The 3 and the 7 are the only sig figs but i guess the zero could count but it won't be a sig fig anymore. It would be considered the first digit of uncertainty.

you should write it as 3.7x10^4 In scientific notation the digit has to be less than ten.

And to answer your question, yes you could do it without scientific notation. you just did it with writing it as 37000

[eirpcalc]

@TheLegendaryOne01 Engineering notation is similar to scientific notation except the exponent of 10 is always a multiple of 3. This is more straight-forward when converting to Kilo, milli, micro, nano, etc. Now, suppose I am using a meter capable of an accuracy of 1 part in 1000. I take 3 readings of my target variable and get 37100, 37000, and 36900. I want to report the average value is 37000. The first zero IS significant. Can I show that without resorting to scientific notation?

[kombatmaster7]

Are you sure 370 is 3 sig figs? I'm taking Physics right now and something tells me that's wrong.

[shazaduh]

@kombatmaster7, yes that's correct, point after 370 makes it three sig figs otherwise without a point its two sig figs.

[kombatmaster7]

@shazaduh Ahhh I see thanks for the clarification.

[bking0704]

Nice now I know what I sometime did wrong during lab reports :P

[MoGaDeX]

I always have trouble with this... Thanks!

[LibertyZebra]

First :D