I'm in year 11, and we have so far had 4 weeks of term, in chemistry class I've learnt next to nothing, that's from 4 weeks! In just half an hour I'm almost learnt all of what has been taught for the whole 4 weeks, thank you very much Prof. Dave!

@yeh.80

3 жыл бұрын

@@amberheard2869 Take care buddy.

@martinmaxwell3508

2 жыл бұрын

Wait..are you 11 years in age or grade? This very material was taught on us on the 10th grade bruh

@keevagrady8316

2 жыл бұрын

@@martinmaxwell3508 year 11 is 15/16 years old

@martinmaxwell3508

2 жыл бұрын

@@keevagrady8316 i see

@martinmaxwell3508

2 жыл бұрын

@@armgord lucky

in case anyone here is unable to go to college and is trying to self-teach themselves college-level chemistry, his videos provide you with everything you need. I'm currently in college and 90% of the curriculum is based off of his channel and his vids. i think im going to drop out because im paying tuition to a college that assigns his FREE youtube vids as homework. It is 100% possible to self teach yourself chemistry, education is truly everywhere and in our faces, its up to us to use it.

@michilovr

10 ай бұрын

But the point of going to college is getting a degree……? Sad to hear that your classes only show videos though :(

The comprehension music is my jam

Much clearer than my university level physics textbook.

I've started chemistry learning in detail by following your practical courses. This channel provides essential information for students and other enthusiastic readers to a better understanding of general aspects of chemistry.

@pola_behr

3 жыл бұрын

damn who's dictionary did you swallow to learn how to talk like that???

I'm in the first grade of high school, and you are the first and only person that got me interested in chemistry. I was always interested in physics and biology, but not this. Thank you Dave, you just made me feel smarter.

Got my finals grade in college for the first semester, thank you Prof. Dave, I passed my chemistry.

If no one can see the humor in Jesus teaching chemistry, then I don't know what to say man.

@rosa578

3 жыл бұрын

the Messiah has finally come to save my Chemistry grades

@KJ-rc6qs

3 жыл бұрын

Lol the name of the lord is sacred thou shalt not put in such a humurous comment

@dlemmuh

3 жыл бұрын

@@rosa578 🤣

@dlemmuh

3 жыл бұрын

@@KJ-rc6qs 🤣🤣🤣

@dlemmuh

3 жыл бұрын

@@user-vo6hl8sp6b ha

I'm going to be using your videos all the time in my class! These set of videos are so helpful!!! Thank you! :)

@ProfessorDaveExplains

9 жыл бұрын

+Marian Iskandar I am most pleased to help teachers in the classroom! Honored to be of assistance. Stay tuned as I upload the remaining 25 or so general chemistry clips over the upcoming weeks.

@martinmaxwell3508

2 жыл бұрын

Time flies..

@edwardlovesonepiece

2 жыл бұрын

@@martinmaxwell3508 for real

@user-xs7gp2cw5i

2 жыл бұрын

@@martinmaxwell3508 indeed

@yawningcheese2238

2 жыл бұрын

@@martinmaxwell3508 yes

Found this for a chem lab and lemme just say *SCIENCE JESUS*

Thank you so much professor :)! the checking comprehension part is awesome.

lawl my science teacher showed us this, and we all exploded with laughter at your intro xD

@ProfessorDaveExplains

7 жыл бұрын

pretty good stuff, no?!?

@sonyduck8663

7 жыл бұрын

+Professor Dave Explains 😜😜

@heyimhershy

6 жыл бұрын

lolol The intro was the weirdest part...In fact, he used the SAME video for the new eighth graders...what a creative teacher

@reamb.5302

6 жыл бұрын

woild've been hella lit

@jr2340

5 жыл бұрын

Daddy Lusa

Holy moly, I thought I understood sig figs, but you explained it way better than my chemistry teacher in a tenth of the time. I found you trough your debunking content and I'm glad I did. I just started the general chemistry series and I can already tell that school is about to get a lot easier. Thank you, Dave.

Hi just want to say thank you for making those videos. They are super helpful when I need to refresh my memory of some old knowledge I learned from school a long time ago. Also I learned all this in Chinese and usually have no idea what the English equivalents are. Your videos especially illustrations help me to pair them up. Thanks!

Hi there, how do we determine the sig fig of uncertainty, standard devaition , relative standard deviation and standard error in analytical chemistry? thank you very much

One rarely mentioned rule is that when multiplying by an integer where no decimals are possible, such as counting, the integer has infinite sig figs. This reconciles the discrepancy that comes from sig fig rules of adding 5 identical values versus multiplying the identical value by 5.

@ProfessorDaveExplains

6 жыл бұрын

yep that's in here too!

@nathanh9935

6 жыл бұрын

For example, if 2.33 x 18 included two measurements, 2 sigfigs in the answer. However, if 2.33 were measured and 18 was a precise count, the answer would be three sigfigs. It wasn't as clear in the video. Don't get me wrong, your videos are great!

This is probably the most useful youtube channel around.

In school we were taught that when you count something then the number has infinite significant figures like 20 books can be 20.00000000...... Books

@ProfessorDaveExplains

7 жыл бұрын

correct! counting numbers have unlimited precision.

Great resource for my students. Thanks

Hi Dave I want to ask you a question about that. For example when I multiply 20 with cos25, should I round the result to 20? Because 20 has the least significant figures. 20*cos25=20? Could you help me?

I wish i had found these videos 5 years ago when i was taking chemistry in undergrad but its nice to relearn with all of these videos

Currently enrolled in AP Chem and this helped me so much!! Thanks a lot!

Thank you professor dave, I struggled with sigfigs for so long

Thank you so much Professor Dave!!

very understandable. thank you, prof.

thank you Sare your videos are very useful to me

thankyouuuu Prof. Dave ! this really help me to undestand significant figures ^^ ♡♡♡

Thank you Dave! Very cool!

Thanks professor 💜️

Why in 3:04 is the answer to question 2 of section 2 20.7 and not 21? Considering the fact that sig figs of 3.8 are 2?

@HamSammichOnRye

5 ай бұрын

Cause it’s addition, only the lowest decimal place (3.8) needs to be in the answer. You’re applying the multiplication rule of sigfigs which is least amount of sigfigs, which you would be right that it needs to be rounded up to 21. The real answer is 20.672, but with addition rule of sigfigs, you need to round to the tenths place = 20.7. 👍

i love this guy so muchhhh, thanks for saving my physic class

How do you come up to your answer in Number 4 calculation? Why it became 4.36?

I was taught that if 5 is preceeded by an even number, round down (1.25 -> 1.2). If it’s preceeded by an odd number, round up (1.15 -> 1.2). The theory is that since 5 is exactly halfway between 0 and 10, it should be rounded up half the time and down the other half, so in the long run it will balance out. Otherwise, when rounding a large number of numbers the result will be biased if 5 is always rounded one way. which is correct?

@seawolf9313

2 жыл бұрын

yeah I was wondering the same

*pauses video and counts people in the crowd*

Heartiest Thanks

In the comprehension I got answer 41.94 for the 3rd one in calculations ..there the ending number is below than 5 so should round down right..? but I can understand that 41.94 is 42 but by the rules I should round down.. prof dave or anybody reply

When you say about the estimation 10000 that is anything between 9500 to 10499, it means you have two sig figs, 1 and 0. But if you say anything between 5000 to 14999, then you have one sig fig.

Im thinking ill go biochem so this is really helpful thanks!

much better than the crash course video on this topic

Thank you!

Professor i have question 162.53+32 then the number of significant figure are?Please must explain professor

I'm rewatching to retain my knowledge from my 11th and 12th grade about gen chem and gen bio to test my knowledge and prepare for my biochem class☺️

Hey, Professor Dave! I just want to ask, in the sample test, isn't the answer to 16.872 + 3.8 should be just 21? because the least number of sig figs is only 2? Thanks :)

@ProfessorDaveExplains

7 жыл бұрын

ah but remember the rules! when adding and subtracting, we round to the fewest number of decimal places, not significant figures.

@kalpeshkumarpatel168

6 жыл бұрын

Alex Ofina

I subscribe just because of that funny intro 😂 I laughed longer than the initial video 😝

Thank you professor!

Hi professor Dave! I really love your videos, and I have learned a lot. I have a question tho, I'm kinda confused, in checking comprehension part 1 number 1 isn't it 8 sig figs is the answer because of rule 2?P.S Prof.Dave might not notice, but if someone knows the answer feel free to enlighten me... thank you prof and to whosoever that'll notice me 02:43

@prawtism

2 жыл бұрын

Rule 3 says leading zeros are insignificant

If I should take the minimal number of minimal decimal places for an addition / subtraction, wouldn't this mean 10,000 + 1 (0 decimal places) is 10,001? This seems to contradict the example when we estimate 10,000 people in the room, and one enters.

Wow! Thankyou Professor.. I have referred many videos for sig fig, but this one really awesome.. Gives me an insight of sig fig.. One question.. If the value is 10,000.00 then is it have 7 sig fig?

@ProfessorDaveExplains

5 жыл бұрын

that's correct!

@WiiAndii

4 жыл бұрын

@@ProfessorDaveExplains Based on the rules given in this video, I'm having trouble understanding this example. If we apply the rules one by one to the given value 10,000.00: 1. Non-zero digits are significant That's one significant digit so far, the 1 at the very start, since all the other digits are zero. 2. Zeros in between other non-zero digits are significant Doesn't change our total of 1 significant digit, since there isn't another non-zero one for anything to go between. 3. Leading zeros are not significant Doesn't matter for this example since there aren't any. 4. Trailing zeros are only significant if they are decimal zeros In my understanding, this would only make the last two zeros in 10,000.00 significant, as all the others come before the decimal point. Meaning that the final answer would be 3 sig figs: the 1 at the start and the two 0s at the end. So if the real answer is actually 7 sig figs, shouldn't rule 2 instead say that any zeros between significant digits are significant, even if those significant digits are themselves zero? Sorry if I'm not making sense, I'm pretty confused since I don't remember hearing about this particular subject in school, and while I could certainly memorize these rules, I am not sure if I understand the reasoning behind them, or even the purpose they serve.

💞❤️Amazing way of Teaching 💞❤️

thank you for teaching me what significant figures are👏👏👏👏

I used this channel when I was younger to learn stuff for fun. Now I'm using it for school...

So a good way to look at sig figs is as if they were an approximation of something?

i learned more in this then two years of chemistry class

0.00024, and 20000 why are these zeroes not siginificant? They do impart some info about our calculation ... can anyone help explain this?

Professor, when multiplying use the fewest number of sig figs. if the question is 6.0 x 3.0, the answer would be 18 or 18.0?

@titidechdamrongwut1351

7 жыл бұрын

Just for clarify the above question, if I use 5 x 3 which both have only 1 sig fig the result would be 15 which has 2 sig figs. but if the rule said use the fewest sig fig then it must show only 1 sig figs in the result, how come for this case?

@ProfessorDaveExplains

7 жыл бұрын

that's right, if five and three were measurements taken on a device that only measures in increments of ten, then five times three would indeed be 2 x 10^1, since we can only have one sig fig! as for the previous question, it's 18, since that has two sig figs.

@titidechdamrongwut1351

7 жыл бұрын

Ah using scientific number 2x10^1. Professor don't you think 2x10^1 have less accuracy than 15? How this rule help science as I believe this is less accuracy. I'm sorry for keep asking questions but your lesson is very interesting.

@ProfessorDaveExplains

7 жыл бұрын

well we have no idea about accuracy, that depends on the situation. but yes it is less precise. however, as is mentioned in the video, we can't estimate beyond one digit further than is inherent in the instrument, so if you were using a graduated cylinder with tick marks for every 10 mL, and you estimated 3 mL and 5 mL for two measurements, you absolutely can't use more than one sig fig, and your calculations using these measurements must obey that degree of precision. but this only applies to measurements, if just multiplying 3 and 5 as counting numbers, sig figs don't apply.

@titidechdamrongwut1351

7 жыл бұрын

Yes professor, I understand +/- when we use cylinder with tick marks and no questions to your explanation at all. But my problem still multiply and divide for example if the car drive at fast 5 m/s for 3 sec. how far the car can go? you could see 5 x 3 = 15 m. And it will be very odd to give the result 2 x 10^1, don't you think so? Note, all 3 things have different unit hence different measuring tools. so why we limit calculation result to sig fig? last, I agree that counting number does not apply but shouldn't all not apply?

Thanks teacher

I'm from Peru and i'm here because i need to learn chemistry in english, thank you very much for your videos

Gap yo'q Dave aka, rahmat!

How do we communicate the difference of an estimation and exact number. If I am wanting to calculate exact numbers to get the most precise study done of people going to night clubs. So then I record exact numbers of attendees every night and one of the nights there is 100% exactly 10,000 what would the standard way of communicating that be? I know we don't always have to follow standards but its often best practice.

@ProfessorDaveExplains

2 жыл бұрын

If you mean to convey exactly 10,000 you would put a decimal point after the last zero.

@cartermilan

Жыл бұрын

put just a decimal point, without adding another 0 after it: 10,000. or use scientific notation: 1.0000 x 10^4

Thank u for helping me even though this vid is before 6 years

this video is so great and fun 😍😎

Surely any number between 5,000 and 14,999 would round to 10,000 in the example you gave. This should be basic maths for me; I can't think where I'm going wrong

Shouldnt the number of sig figs be defined by the measurement method? For example, if your instrument measures to two decimal places but you get a measurment of 100. Wouldn't that cause some issues? Please tell me if i am missing something.

@ZSmith-yy4lv

11 ай бұрын

If your instrument (let’s say a scale here) measures to two decimal places and you have an object that weighs exactly 100g, then the scale would read 100.00g. Because the two zeros are decimals, they are significant figures, meaning the measurement has 5 sig figs. Did I understand your question correctly?

@AlphaOfCrimson

11 ай бұрын

​@@ZSmith-yy4lvOh you are right! I forgot about the trailing zeros part of the explaination. Thank you for that.

@AlphaOfCrimson

11 ай бұрын

To me this seems to be standardization for dealing with estimations due to the obvious lack of perfect precision in the real world. So I was wondering why we wouldn't use the precision of the measuring method to define the number of sig figs. Though my question was erroneous, I was attempting to point out a possible flaw. So my question still stands when dealing with whole numbers. For example, if your measuring method is precise to the hundreds place but your value happened to be 100000.

@ZSmith-yy4lv

11 ай бұрын

@@AlphaOfCrimson if you had something that weighed 100,000g and a scale that only measured increments of 100, it would ideally have 4 sig figs if I’m not mistaken. To convey this, you could always write the measurement in scientific notation as 1.000 * 10^5.

Hey professor, I wanted to ask why 1000.09 has 6 sig figs but 54700 has only 3, as you said that the zeros that we take in consideration are the zeros after decimal so 1000.09 should have only 2 sig figs I.e 1 and 9

@ProfessorDaveExplains

3 жыл бұрын

zeros in between non-zeros are significant

@ansh9055

3 жыл бұрын

@@ProfessorDaveExplains thank you so much for replying so fast :) your channel is really helpful

i'm sorry Professor, I'm a little bit confused to the rule. what if we multiply point number 3 in the calculation board into (2.33 x 17) instead of (2.33 x 18), the result would be 39.61. Now, because it should be 2 sig figs, then we must round it down first (39.6), because it still 3 sig figs then we round it up, so we get 40 right, But you said once, the trailing zero rule, if 35000 has only 2 sig figs, then 40 has only 2 sig fig, we know it contradicts to each other in that case. What should we do for that? Thank you, Professor Dave.

@muhammadalthaf6304

4 жыл бұрын

i mean 40 has only 1 sig fig, while the rule for multiplication and division is that the answer must have the fewest sig figs. but in this case where it should be 2 sig figs (because of 17), now it has only 1 sig fig.

@ProfessorDaveExplains

4 жыл бұрын

it would be 40. with a decimal after it indicating that the trailing zero is an exact number and therefore significant

@muhammadalthaf6304

4 жыл бұрын

so the key is that the 40 in this case cannot be seened as the way that 35000 represents, because it is an estimation, while 40 has decimal after it. hmm, i got that. Thank you very much, Professor.

I needed this because I STILL don't 'get' why zeros AFTER the decimal point, but before the first non-zero digit, aren't significant. If you KNOW you've got 35 millionths of an inch, 0.035000in, why isn't the tenth of an inch 0 'significant'? Accurately measure down to the millionth of an inch, by definition you've accurately measured the tenths also. It's probably just a subtlety in use that makes sense when you start doing calculations and want to keep the number of significant digits consistent, so that your measurements and figures can be reliably duplicated by others, without getting kinked up with rounding errors and so forth. I wish I didn't have this nagging little feeling that I'm missing something, but the video is consistent with what I remember being taught, and the rules are unambiguous, so it's just a little quirk I'll have to DEAL WITH!!! 🙂

@cartermilan

Жыл бұрын

leading zeros do communicate information about a number, but they are not significant because they don't convey any information about the precision of the measurement. to understand this, imagine you measure something as 5.2 cm, which has two significant figures (one measured + one estimated digit). you can also represent the same value as as 0.052 m; you've gained two leading zeros, _but the precision of your measurement has not changed,_ so they cannot be counted as significant figures.

@abcde_fz

Жыл бұрын

@@cartermilan Thanx for clarification. I'm not great with math on paper, and I remember having a little trouble with this way back in my school days, so I appreciate it when I can learn or relearn something. Even when I rarely encounter this or that factoid in day-to-day life, there's no such thing as too much learning! 🙂

fam i for sure got 1 right on the whole comprehension check

2:04 looking at this 10,000 example which has one sig fig, you say that anything between 10,499 and 9,500 gets rounded to 10,000. why is the range +499 and -500 of the number? shouldn't it be +500 or -500? shouldn't the upper range be 10,500 instead of 10,499?

@VaishnavENK

3 ай бұрын

0.5 is conventionally rounded up (to 1)

Nice

How would I notate that I know that the crowd has exactly 10,000 people? for instance if I counted every single person in a building and just coincidentally it was exactly 10,000 how can I notate this?

@ProfessorDaveExplains

2 жыл бұрын

10,000. with a decimal point like that

way better explanation for sigfigs then my chem teachre

any pathwasians??????

This video was used for an EdPuzzle in my chemistry class. Just thought you should know.

how many significant figures are in 100.0 because the 0 in the decimal counts as a significant figure so do the zeros between the 1 and the zero in the decimal count as significant figures?

@ProfessorDaveExplains

3 жыл бұрын

yep, that would be 4 sig figs

@oooooooooo7315

3 жыл бұрын

Thank you, and thank you for working on those videos, they help a lot! 😃

2:04 isn't that wrong? You're saying that 10,000 has one sig fig but 9,500 and 10,499 both approximate to 10,000 only if the first zero after 1 is also considered a sig fig. If not, then 5,000 and 14,999 both approximate to 10,000. Where am I going wrong?

I do not understand why 0.00004050 has 4 sig figs instead of 9. Aren't the 0's there certain? If I measure some to the precision of 8 decimal places, how can the 0's be uncertain?

@ThePejsek02468

7 күн бұрын

Let's say you are measuring a surface area of a rectangle. You measure one side with good precision as 0.004 m, and the other side with poor precision as 372 m. If you multiply, the result is 1.488 m^2. The number with the fewest sig figs was 0.004, which has one sig fig. So the actual result is 1 m^2. If your proposition was correct, then the number with the fewest sig figs would be 372, which has three sig figs, thus the result you would get from the multiplication would be 1.49 m^2. However, if the actual dimension of the first side is closer to 0.0044 m, you still measure it as 0.004 m. Substituting 0.0044 m gives you 1.6368 m^2. That is very different compared to your result of 1.49 m^2. This also shows that the last sig fig is uncertain. It could be one more or one less. In this example, you measured area of 1 m^2 with the precision of + or - 1 m^2 (pretty bad).

Yeeeh the intro's fire

Sir how many significant no. In (4020 Km = ) and (640500 = ) plz ans me sir....

@ProfessorDaveExplains

6 жыл бұрын

3 and 4

2:35 you said 9.365 rounds to 9.37 but It says "if it is 5 then the digit before it affects the answer by its parity (odd / even)" in my textbook. And I think 9.365 rounds to 9.36 because 6 is even.

@ProfessorDaveExplains

3 жыл бұрын

No, the 5 makes it round up.

@hamdimohammed2541

3 жыл бұрын

@@ProfessorDaveExplains Ok, thanks.

India's Ncert Book Has Diff Rules For Sig figs and the rules of calculations.

Sir any effect of unit in significant no....

@ProfessorDaveExplains

6 жыл бұрын

nope

@kalpeshkumarpatel168

6 жыл бұрын

nope means ?

@ProfessorDaveExplains

6 жыл бұрын

units do not affect it

Why do we need to know the number of sig figs? Aren't we supposed to give the exact numbers that come when doing a calculation? Are we always supposed to round them to sig figs up?

@ProfessorDaveExplains

5 жыл бұрын

when reporting measurements and doing calculations using measured values, it is very important to report values with a level of precision that is dictated by the measuring instrument, no more or less

@thnxm8

5 жыл бұрын

@@ProfessorDaveExplains Oh great! Just as I understood it.

@thnxm8

5 жыл бұрын

@@ProfessorDaveExplains Thanks for answering btw

sir Questions no 2 of part 3 of answer is wrong

@ProfessorDaveExplains

7 жыл бұрын

not sure which one you are referring to, but they are all correct.

@user-hb6ps6bt6w

5 жыл бұрын

@@ProfessorDaveExplains 54.700---- 5 sig dig

if you actually counted everybody in the crowd and got 10,000 people and then a person joins the crowd are you still not allowed to say there are 10,001 people? and if you invited 500 people to a party and then added 30 more people do you still reserve 500 seats since there is only 1 sig fig.

@ProfessorDaveExplains

7 жыл бұрын

well if you've literally counted, yes. but this is talking about an estimation, a measurement, and the uncertainty that goes with that estimation. it's just an analogy.

@titidechdamrongwut1351

7 жыл бұрын

I think the explanation of +/- is NOT using sig fig but using number of digit, isn't it. If you can count one by one up to 10,000 heads you got 10,000 with zero digit and when you add or subtract this number you still got zero digit with no any round up require.

@MrWizardjr9

7 жыл бұрын

Professor Dave Explains also my chemistry teacher told us there are instances where you dont use sig figs because if you do you will get a wrong answer and when i asked her how would you know she said i just will and of course i didn't know and got a question wrong on a test, im still really salty about that. So how will you know when not to use sig figs

@ProfessorDaveExplains

7 жыл бұрын

kinda sounds like your teacher doesn't know what she's talking about! if the values come from physical measurements, sig figs always apply. if they are for unit conversions or are counting numbers or something that has nothing to do with the act of measuring, then they don't apply.

Unit of measurement 0:18

Find the first and last non-zero. Anything in between is a significant figure. I thought the last rule was the reverse. Is there a reason for much of this?

@ProfessorDaveExplains

7 ай бұрын

But trailing zeros are significant if decimals.

@GeorgeDCowley

7 ай бұрын

​@@ProfessorDaveExplainsIs this a correction, or a follow-up?

@ProfessorDaveExplains

7 ай бұрын

Just adding to your method

@GeorgeDCowley

7 ай бұрын

@@ProfessorDaveExplains Actually, learning about trailing zeros was the reason I came here. Is it true that you have to write 1.98 to two significant figures as 2.0? If so, why?

@ProfessorDaveExplains

7 ай бұрын

yes, that's how rounding works

2:44

👍!

Thank you sir! I've learned a lot..

Damn this all began 7 years ago

I certainly hope you have learned more than just Significant figures on 4 weeks!

Very helpful video! I'm a chemistry major and lol my exam is in 3 hours

nice merch!!!!!!

I wanted to know the reason of these rules... That would have been a physics video

People with dyscalulia have entered the chat, im one of them😂😎 I'll have o review it a few times, but its still more understandable then my school books would have been.

Good gob

👍👍👍

You’re pretty awesome! Wish you were my uncle

If 500 and 500. are exactly the same, why does 500. have 3 significant digits and 500 has only 1. Isn't 500 without the two zeros become 5 (with the same number of significant digits) and those 2 zeros after the 5 are super significant because they give you the correct place value of the 5 before them?

@ProfessorDaveExplains

5 жыл бұрын

They aren't exactly the same, at least not in the context of scientific notation. 500 is precise only to the hundreds place, implying that it could represent anything from 450 to 549 while 500. means it is precise to the units place, so it could be anything from 499.5 to 500.4 because of the decimal listed.

Ok