Significant figures

Please tell me if I'm understanding all this correctly - • the significant figures in a given reading are all going to be consecutive digits, and of those consecutive significant digits, the last one is the one we're uncertain of, while we're certain of the rest. • When we're writing down a reading made using a generic ruler, with its smallest unit being 1 millimeter, the reading cannot be something like 2.33 cm, it can only be 2.3 cm, even if we feel like the former reading is closer to the real value, judging by eyeing the gap between the 23 mm and 24 mm lines on the ruler. • If we can see that the reading is equal to or greater than 2.35 cm, do we write down 2.4 cm or 2.3 cm?
59 Replies
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Nimboi
Nimboi2mo ago
1. yes. last one uncertain as in, could be + or - 1 because of any discrepancies in precision 2. yes 3. if this is for an actual lab experiment, doesn't matter tbh, its your call, and both values are within the limits of experimental error. just don't write 2.35cm.
Sam_2207
Sam_2207OP2mo ago
the last one isn't for an actual experiment, i just wanted to know what would be the correct thing to do, since the whole point of making sure that our reading has the right number of significant figures is to relay how accurate our reading is @Nimboi would you happen to know (´。_。`)
Nimboi
Nimboi2mo ago
well maybe then you could eyeball it but convey the uncertainty so if you see that the reading looks closer to 2.4 instead of 2.3, but you still want to convey the uncertainty, you could write 2.4 +/- 0.1 or 2.4 +/- 0.05 or just explicitly say in words that "the reading is in between 2.35 and 2.4cm" it is scientific to look at the ruler, just don't accidentally pretend that the measurement is precise ofc, i aint a scientist
Sam_2207
Sam_2207OP2mo ago
Roger 🫡 shukriya! I forgot how to close the thread and thank you for solving my doubts
Nimboi
Nimboi2mo ago
no problem :)) you type +solved @the person who solved your doubts tooting my own horn rn
Sam_2207
Sam_2207OP2mo ago
One last thing
Sam_2207
Sam_2207OP2mo ago
No description
Sam_2207
Sam_2207OP2mo ago
@Nimboi I'm sorry for bugging you this much 🙇 Wait Ig 0.0 has 1 sig fig… But if our reading is just 0 Does that reading have 0 sig figs? That's so weird And if our reading was 1 we'd have 1 sig fig
Nimboi
Nimboi2mo ago
nahh honestly it's very refreshing to see someone actually curious about the subject both have 2 sig figs
Nimboi
Nimboi2mo ago
Socratic.org
How many significant figures are in 0? | Socratic
Zero When there is no decimal point, you ignore the zeros in terms of counting significant figures. If the question had asked how many significant figures are in 0., then there is one significant zero.
Nimboi
Nimboi2mo ago
all u gotta do when thinking about sig figs is see if a digit improves the precision of the reading the 0 before the decimal point makes the reading more precise (by narrowing it down into a range of 0-0.999...) the 0 after the decimal point also makes the reading more precise (by narrowing it down into a range of 0.00000... - 0.09)
Sam_2207
Sam_2207OP2mo ago
but, supposing that reading is written in centimeters, if we write it in meters, it'd turn into 0.000, and if we count the number of significant figures according to you, there are now 4 significant figures, but the number of significant figures shouldn't change just because we changed the unit of measurement in which we're reporting our reading but if our reading is "0" instead of "1", isn't it still relaying the measurement to the same level of accuracy? and i wouldn't say that there is no information being relayed either...
Nimboi
Nimboi2mo ago
you're correct, but to avoid confusion, if the reading is 0 then we just write it as 0. with a decimal instead i think scientific notation avoids this problem hang on lemme send a link im a lil rusty myself
Sam_2207
Sam_2207OP2mo ago
alright
Nimboi
Nimboi2mo ago
okay i think i got it in the case of 0, you write it as 0 in any unit because 0 just indicates nothing "no length/volume/whatever" its a bit dodgy there for non zero numbers, you maintain the same amount of significant figures 0.5 cm would be converted to 0.005 m, which both have 1 significant figure while you think that both of them look different, the way its generally conveyed that its the same amount of precision is to write it as 5 * 10^-1 cm or 5*10^-3 m, where only 5 is counted as the sig fig (this is scientific notation) it doesn't look like a perfect system but it works
Sam_2207
Sam_2207OP2mo ago
If we measure 0 cm using a ruler, doesn't our reading indicate that the length of whatever we were measuring lies between 0 cm and 0.05 cm? We are measuring something after all
Nimboi
Nimboi2mo ago
scientifically speaking, your ruler cannot measure a reading between 0 and 0.05, however you can add a personal note that it looks like the reading is between those 2 numbers (conveying the uncertainty as +/-) or normally, you just get a more precise instrument
Sam_2207
Sam_2207OP2mo ago
Hmm
Nimboi
Nimboi2mo ago
its a human made system, its not gonna be perfect but if it works, it works
Sam_2207
Sam_2207OP2mo ago
I guess so I'll have to take a minute to take it in though But I think this explains it Thanks a lot!!
Nimboi
Nimboi2mo ago
your respect for knowledge is admirable i love it its not just "look at it and move on"
Sam_2207
Sam_2207OP2mo ago
Thanks but it doesn't seem like I'll be able to go far
Nimboi
Nimboi2mo ago
eh i feel the same sometimes but in the end who gives a shit
Sam_2207
Sam_2207OP2mo ago
I tried changing a bit
Nimboi
Nimboi2mo ago
if i feel profound, i feel profound i hold that value very close to me, if i were asked to pick between my curiosity and going to college, i'd pick my curiosity
Sam_2207
Sam_2207OP2mo ago
😆 ig that's true. I should think that way as well.
Nimboi
Nimboi2mo ago
we'll get there! all college does is catalyze your development and that's great, you should be working for that but it's not the end-all be-all what takes an IITian 4 years to do, you could do in 10 does it matter? not really, atleast after those 10 years
Sam_2207
Sam_2207OP2mo ago
I don't think I'm the kind of person who'd be able to do much on my own, unlike yourself My environment affects me a lot and
Nimboi
Nimboi2mo ago
i do fuck all on my own 💀 but i'm working on that
Sam_2207
Sam_2207OP2mo ago
Well Yeah
Nimboi
Nimboi2mo ago
the more you look into the long term, the more your enthu matters
Sam_2207
Sam_2207OP2mo ago
😭 well good on you for trying ig
Nimboi
Nimboi2mo ago
i told myself that after 12th and entrance exams are over
Sam_2207
Sam_2207OP2mo ago
I'm gonna try too Try to study, which I haven't done since 2020
Nimboi
Nimboi2mo ago
ill sit down and read einstein's relativity paper whatever i don't understand, i'll google no time constraints, no exams ought to be therapeutic as hell riyal
Sam_2207
Sam_2207OP2mo ago
That sounds cool
Nimboi
Nimboi2mo ago
yeh :D all i gotta do is make it thru now
Sam_2207
Sam_2207OP2mo ago
My mind is at the level where thinking a little stresses me out so it'll take me a few years before I'm able to say something like this
Nimboi
Nimboi2mo ago
stresses you out as in you don't feel good enough?
Sam_2207
Sam_2207OP2mo ago
I feel uncomfortable thinking Doesn't matter if it's studies or my interpersonal relations
Nimboi
Nimboi2mo ago
your curiosity didn't give me that impression but that's just a matter of time our brains get better at things the more we do them akin to going to the gym
Sam_2207
Sam_2207OP2mo ago
That's what I'm betting on
Nimboi
Nimboi2mo ago
when i look back at my 11th self and think about what i wasn't able to do
Sam_2207
Sam_2207OP2mo ago
Wonder what'll be of my friendships by the time I start thinking properly
Nimboi
Nimboi2mo ago
i often go "was i fucking dumb or what" but its nice its a sign of progress my perspective is, just being able to think about whatever i want to is my ultimate freedom i cannot believe i landed in a lucky enough spot to like science, and even if i'm not good at it right now, or maybe ever, i can still enjoy the shit out of it
Sam_2207
Sam_2207OP2mo ago
That's me when I think of how I didn't realise how creepy I must've come off, staring at my crush back in 8th
Nimboi
Nimboi2mo ago
lmaooo character development hits hard
Sam_2207
Sam_2207OP2mo ago
Science does seem so cool when you think of how much we've pushed the boundaries of our realities with time It's like a superpower
Nimboi
Nimboi2mo ago
exactly dude
Sam_2207
Sam_2207OP2mo ago
Thingy
Nimboi
Nimboi2mo ago
and we were born in such a position that we understand it we are the universe looking back on itself
Sam_2207
Sam_2207OP2mo ago
Yeah Sho cool
Nimboi
Nimboi2mo ago
ight ima go study mafs try not to jump off challenge
Sam_2207
Sam_2207OP2mo ago
Roger
Nimboi
Nimboi2mo ago
byebye
Sam_2207
Sam_2207OP2mo ago
Bbyee +solved @Nimboi
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