Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App! Download it here for Apple Devices: apple.co/3d4eyZo Download it here for Android Devices: bit.ly/2SrDulJ
You Crash Course guys should make a site that tests us on the information so we can see how much we are absorbing from each episode. (Yes, I'm that person that WANTS to test.) Thank ya'll and keep up the good work!
+LJ Fleming my tought exactly. exept for the current ammount of 1,22 million (yeah, its a comme over there, greets from europe. lets wait for a unification on to settle this topic someday)
completely agree with the sig figs thing i have to use outside resources to understand what was taught in class and i thought ib chemistry hl was difficult just because it was ib chemistry hl
My teacher told us one simmilar to that. it's "What do you do with a sick chemist? Well if you can't Curium, and you can't Helium, you might as well Barium."
This still bugs me. They added an annotation correcting the 310 error, but there's no annotation for the light years per second calculation. They got the completely wrong number for it! The correct answer should've been 2.8 x 10^-15 ly/sec, it is not 9.3 x 10^-12 ly/sec. *_It's been nearly 4 years now, how am I the only one that's noticed this!_*
Annie Reller Lol! Maybe we really are only two of the seven people that worked along with Hank on our calculator. I remember noticing this mistake when the video was first uploaded back in 2013, I'm shocked that no one's pointed it out to Hank by now.
THANK YOU I THOUGHT I WAS CRAZY AND imalready confused so that why i watched this video and i was freaking out cause i though i finally got it but it wasnt what he got haha
"You know what we do with liars in chemistry?" WAS REALLY WAITING FOR YOU TO SAY "BARIUM" HANK c'mon. oldest chemistry joke in the book. :p but also, very good video! I've been watching your series all night. Thank you for teaching me in a way my chem professor couldn't.
I only just started taking college level chemistry and thought my teacher was just being overly stern about representing significant figures. Now I realize he's actually trying to save my life.
Brian Ung it's the speed of light per year. now the speed of light part is probably the least arbitrary thing you could pick, but i've got a problem with the year part. our year is based on the time it takes for this one particular planet to make one trip around our star. that part is completely arbitrary.
Huntracony but the "year" is a set amount of hours, minutes, and seconds. albeit an amount of time that, if measured now, would differ from the original or standard calculation. but while our planetary rotation may have changed, the speed at which light is capable of traveling within that arbitrary, but defined, figure remains constant... Or does it?
Geordi La Forge well, in leap years light suddenly gets a whole other day to travel, which suddenly increases the distance of the lightyear. so even though the speed of light remains constant, the lightyear does not. now that's of course not how it works in science because it'd mes everything up, but that is what a lightyear is.
I didn't realize Crash Course had a chemistry video on unit conversions and when I found this I nearly started crying out of happiness. Unit conversions are very difficult for me.
I am fairly new to CrashCourse. I started watching last year for Anatomy and the body systems. I did really well because of CrashCourse. So, here I am, back again, thrilled to find Chemistry by CrashCourse! This was one of my favourites. Simply because of "...what we do to liars in Chemistry...". I laugh so much through the episodes my family wonder what is wrong with me!
Maybe an annotation is needed to correct the start of the video - the IPK no longer defines the kilogram, it is now defined as 6.0221408418x10^23 atoms of silicon-28 (Avogadro's Constant).
am i the only one who to understand this has to wtach like 3 times. then in slow motion. then backwards. then ask my father. then not understand and move to next episode?
Yeah you sound like me. Keep trying though. Im persevering with Science and Maths because i have a genuine interest even though they make me feel like im thick..
You are not alone. But trust me, just paying attention in math, physics and chemistry in school, and some practice (homework), will make this a very simple subject. Everything is challenging at first.
Pause when you have to take something in which you know you won't understand just by quickly brushing past it. It helps me to write it down also for reference.
God, I wish you were my Science/ chemistry/ bio/ teacher. -_- OH you should do world tours. Not just in university's though. Like in high-schools and stuff.
AquiredCents Yeah I've seen that show! It was amazing! It really made me think a lot about astronomy and whats really out there in the big wide universe.
Iffshah Jaffery Yes but you said ' idle school' maybe you meant middle school but spelt it wrong. But I did not know you were British, I'm just saying that I'M not american. You said: "You Americans" :P
I just wanted to say, I've been watching you SciShow for over a year now, and now since I just started honors Chem, it is so cool to actually learn school information for you. It is like you have moved from the entertainment part of my life to the school part, which is a really weird feeling. My chemistry class is already very interesting, but now my brain is processing it as raw entertainment. And for that I thank you. Genuinely, Paul Wyrough
I know almost nothing about chemistry, I suck at math, and I did not find this episode - or any of the ones I have watched thus far - difficult to comprehend at all. Thank you. :)
I did as well. So annoyed cause I spent 15 minutes stressing about how to find the right answer. It really ISN'T as simple as "hammering" figures into a calculator!!
I am refreshing my brain with this videos, I find them Quite interesting. and like my dad always says , you have to learn twice , once you are a kid and second when you are a dad.
In the significant figures section he multiples 60 x 5.0839. He says that 60 is two significant numbers but isn't it only 1? Trailing zeroes are not significant. So that answer should be 3 x10^2 and not 3.0 x 10^2
I thought this was the definition of a second: The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.
+arjenbij and the meter is defined as 1/299,792,458th of the distance light travels in a second (or the distance travelled in 1/299... seconds). Other definitions are still being worked on, though I believe two other constants are being based on planck length and the elementary charge.
I'm not sure of the exact count, but yes, time and distance have been defined by counts of the hyperfine state resonance in an inertial frame and the speed of light. Those might not be absolutely constant, but sure seem to be.
There's the thing saying sorry about them messing up the number and stuff, then he proceeds to say, "And do you know what we do with liars in chemistry? We kill them". Hank, I'm sorry in advance for what's going to happen.
agree that km/h isnt much better, but it is easier to convert to lower units because of the standard base of si units(10). Converting miles to inches on the other hand, good luck.
Guys, don't be dismayed. The calculations seem to be wrong for some reason, as people said in previous comments. 60 m/h are equal to 2.8*10^-15 ly/s, because in the end you will be dividing 1 by 60*5.9 and multiplying the result by 10^-12, which in turn will leave you with a result of 0.0028*10^-12.
The difference between watching this at the first week of chemistry class and the 4th week of chemistry class is remarkable... Literally helping me study for my second test.
Hi there, I got the same answer as you, except with 10^-15, even after I put the conversion through Google. Can you please confirm, or is there something important I'm missing? Thanks!
9:55 - I understand that we need to round to 2 sig figs in the final answer, but I thought you round the answer to 310 or 3.1x10^2? I thought you do that because the 5 in the ones place is right next to the 0 in the tens place, so you round up?
Correct me if I am wrong, but at 10:00, I believe the actual number should be rounded up before the insignificant figures are omitted, which makes the number 3.1x10^ 2.
note to self: sigfig rules, also use scientific notation do not include lying numbers!! add/sub: number w fewest figures after decimal point decides how many decimal points should be there mult: same number of sig figs as least number of sigfigs use scientific notatuon to signify inaccuracies
Wait, for the one where it says 60*5.0839, shouldn't the sig figs be 310? I learned that you have to round the sig figs. and you can keep it as 310 because the 0 is not significant unless it was .310 in which it becomes significant. If you wrote it in scientific notation it would be 3.1*10^-2
"you know what we do to liars in chemistry? we kill them" - Hank Green. "Life is getting better comrades! Life is gett-" - Stalin dies Hank Green: Life, like everything is science and chemistry
I love that he opened with the often overlooked fact that units of measurement are completely arbitrary. Got my attention right away. I've never understood significant figures before today, and now it makes perfect sense! Thank you!
So Hank, fun fact from my engineering lab. You had a little apology at the top near the end for rounding the 5 down, but that is actually correct for scientific rounding. Scientific rounding is set up so that if the preceding number is even, you round down so its stays even, and if it is odd, you round up so it is then even. It is different from "Normal" rounding because, statistically, it should produce just as many round ups as it does round downs instead of causing a slight inflation. Since this video is for chemistry, scientific rounding would be correct and the math done in the video is thus correct as well.
其实五后面还有非零数字，应该进一，感觉视频错了 Google Translate: In fact, there are nonzero digits after five，should Rounding up to one. I think the calculation in the video is wrong.
Joe Wong If I am not mistaken, the 6 is the only sig fig in the number 60, since no decimal point is present. Trailing zeros are only counted as significant figures if and ONLY IF a decimal point is present. If the number was 60. then there would be 2 sig figs in the number, or 60.0 would be 3 sig figs, and so on. However there is no decimal point in the example shown in the video. That makes the least amount of significant figures only 1, so the original 300 is correct.
Jennifer Stephens Actually, it's even worse than that: You need to know the resolution and fault margin of the measuring device. The speedometer in a car in Europe, and I guess in the US too is deemed OK when the real value is between -12% and 0% of the measured value, with standard tyres (new tyres inflated to rated pressure and nominal temperature)... This means if your speedo says 60 MPH, you can be driving between 52 and 60 MPH, which would mean that there is not a single SF valid. So in the end the Speedometer isn't a measuring device but a guessing instrument.(In a truck in Europe, the speedo is regularly calibrated, but tyre -wear and -inflation may be used to cheat a bit)Your GPS system is more accurate, and there I would dare to keep 2 or 3 SF's valid. In this case, to come back to the O.P., 305.00* would indeed be noted as 3.1*10²
Hi. just a guy from the future (it ain't pretty). just came by to say that the first conversion was incorrect the correct answer was 2.81x10^-15 ly/s for me
myself and my college pro love your videos. we discuss almost weekly in class about you and how you make it easier to learn or how what we are doing in class relates to what we have seen on crash course ! i encourage my class mates to also watch these videos
at the end i thought he'd make some sort of joke or pun about the whole thing, or try something clever, and then just "we kill them" idk, maybe cause i've had no sleep, but im dying XD
***** Sorry but no. The initial numbers are accurate down to the one's place. Because of this, the result will also be accurate down to the ones place. Having the result be an order of magnitude higher does not change this.
While I do understand that significant figures are awesome and necessary, I do find them a bit tedious sometimes. For instance, if I want the mass of a water molecule, I can refer to my high school periodic table. It tells me that oxygen weighs 15.999 g/mol and hydrogen weighs 1.0079 g/mol. I understand that both numbers have the same number of significant figures, which is very important, however it can trick me into thinking that they must have weighed the hydrogen with a more accurate tool (which in scientific research is a cardinal sin), when in reality they're just obeying the laws of significant figures. Sincerely, A forgetful chemist.
Sig figs in calculations finally clicked for me after watching this. The way the textbook was describing it was just not working for me, and this video provided the connections that I was struggling to make on my own. 10/10
Pssst... we made flashcards to help you review the content in this episode! Find them on the free Crash Course App!
Download it here for Apple Devices: apple.co/3d4eyZo
Download it here for Android Devices: bit.ly/2SrDulJ
k
YESSSSSSSSSSS
Very nice
Hank in 2013: "maybe 50-100k views"
2019: 2.7M views
2020: 3M
You mean 2.7*10^6?
Timur The Terrible we love our profile picture
I'll remember that next time when I fail my test: "At least you didn't fail your mission to Mars" lmao
What’s this is reference to?
Fr tho
"Do you know what we do to liars in Chemistry? We kill them" -Hank Green
Should've been my senior quote smh
I was about to comment that
Like accidentally, right?
yet, that's just besides the point.
simplymaci tyler smith was first.
simplymaci its gonna be mine 😂
When Hank established his street cred
You Crash Course guys should make a site that tests us on the information so we can see how much we are absorbing from each episode. (Yes, I'm that person that WANTS to test.) Thank ya'll and keep up the good work!
Khan academy
I want it too!
I agree with you on this one.Crash Course please do it
it happened now lol
They made an app
I swear Crash Course is the only reason I'm doing well in school
Sarah Fullerton-Barrios 👏👏👏
I’m still a bit confused because my teacher haven’t taught me this yet.
Well , how well?
So true
"-And you know what we do with liars in chemistry? We kill them" -Hank, 2015
Tyler Smith Best quote ever!
*****
I fell down laughing after reading that
Ok now im obligated to tell you a chemisty joke
Did you know alcohol isnt the problem.
Its the solution!
When you have a chemistry test tomorrow and you don't understand sig figs so much you use Hank to help
ME AF. Lmao, I have my first exam for chem fall. I'm freaking out because conversions and significant figures bug me. I'm just going to kms
girl same
Kaitlyn Carroll get better at maths
Kaitlyn Carroll same tho
Me😂
5:26 Calculator says boobs.... very funny Hank.
everyone is low-key immature
05:29
5:30
BIG OOf
Jason Hurle it says 80065
*tells a lie in chemistry class*
*remembers this video*
*starts sweating profusely*
50-100k views: Hank's prediction.
1000000 views: reality
+LJ Fleming Which means a solid 70 to 140 people did the math along with him.
Professor Syndicate Yep
More like 7.0 x 10^1 - 1.4 x 10^2
needpit1 Yep
+LJ Fleming my tought exactly. exept for the current ammount of 1,22 million (yeah, its a comme over there, greets from europe. lets wait for a unification on to settle this topic someday)
you have explained sig figs better then my teacher and i'm taking a summer class for chemistry. I'm awful at it. Thank you.
completely agree with the sig figs thing
i have to use outside resources to understand what was taught in class
and i thought ib chemistry hl was difficult just because it was ib chemistry hl
I came here to help with chemistry but I was also struggling with unit conversions in physics
oh no baby what is you doing??
Wait. Your name can be spelled with a lowercase letter. Green or green. Name or color. So you are a great person.
We don't kill liars in Chemistry... we Barium. Missed obvious joke opportunity.
Hahahahahahah!!! That is a great pun!
My teacher told us one simmilar to that. it's "What do you do with a sick chemist? Well if you can't Curium, and you can't Helium, you might as well Barium."
thats not funny
Michael akinkunmi Yes it is.
Lol
"50 to 100 thousand views"
*video has nearly 650 thousand views*
UPDATE: *video has nearly 2 mil views*
It is sad that this doesn't even have a million views and Justin Bieber has 3-4 million views. mariaarakal
FROP DESAI tru dat
FROP DESAI How is that sad?
mariaarakal modesty
SpadaccinoLuciano It's sad because Justin Beiber has absolutely no talent and does not deserve the number of views/followers he has.
This still bugs me. They added an annotation correcting the 310 error, but there's no annotation for the light years per second calculation. They got the completely wrong number for it! The correct answer should've been 2.8 x 10^-15 ly/sec, it is not 9.3 x 10^-12 ly/sec. *_It's been nearly 4 years now, how am I the only one that's noticed this!_*
THANK YOU!! I was just resolving this problem for 30 min and kept getting the same answer- and this is the only comment addressing it
Annie Reller Lol! Maybe we really are only two of the seven people that worked along with Hank on our calculator. I remember noticing this mistake when the video was first uploaded back in 2013, I'm shocked that no one's pointed it out to Hank by now.
+David Bridges haha wow, i just spent an hour doing that problem over and over i thought i was doing something wrong
I agree he messed up the calculation.
THANK YOU I THOUGHT I WAS CRAZY AND imalready confused so that why i watched this video and i was freaking out cause i though i finally got it but it wasnt what he got haha
"And do you know what we do with liars in chemistry? We kill them!"
-Hank Green 2013
Awesome!
"You know what we do with liars in Chemistry? We kill them"- Hank Green, secretly a supervillain.
Hank: Do you know what we do with liars in Chemistry?
Me: What, Hank? This is bound to be witty.
Hank: We kill them.
Me: Oh. *terrified*
I thought he was going to say we Barium
gamerathletemusician lol
"You know what we do with liars in chemistry?"
WAS REALLY WAITING FOR YOU TO SAY "BARIUM" HANK
c'mon. oldest chemistry joke in the book. :p
but also, very good video! I've been watching your series all night. Thank you for teaching me in a way my chem professor couldn't.
In chemistry, we kill liars by pouring strong acids on them, followed by titrating some bases on their bodies
savage
Or we put them in a thing of boiling steel
nah thats totally a lye...
thus, finally making them neutral
But after reacting an acid with base there is a formation of salt, so what happened to it?
Let's create a new unit of measurement called: the hank!
The hank is a unit representing one actual view of a youtube video, for each predicted view.
I would suggest "greens" as a measurement of awesome.
+Pink Wings I'd go with hank.
This video has 1.2624 x 10^1 hanks.
12.6688 hanks now
Pink Wings Who the eff is Hank?
I've watched this episode around 7 times, and now I understand it finally. Thanks for these videos Crash Course Crew! It's really helped a lot!
I only just started taking college level chemistry and thought my teacher was just being overly stern about representing significant figures. Now I realize he's actually trying to save my life.
"Do you know what we do to liars in Chemistry? We kill them" - Hank Green. Very good teacher. Hank Green for president!
I love my chemistry professor, but.. I'm just learning better here. This guy's sense of humor cracks me up.
but light years are also arbitrary, because years are arbitrary.
i laughed but then i realised light years is measure by speed of light, so speed of light isnt arbitary?
Brian Ung it's the speed of light per year. now the speed of light part is probably the least arbitrary thing you could pick, but i've got a problem with the year part. our year is based on the time it takes for this one particular planet to make one trip around our star. that part is completely arbitrary.
Huntracony
but the "year" is a set amount of hours, minutes, and seconds. albeit an amount of time that, if measured now, would differ from the original or standard calculation. but while our planetary rotation may have changed, the speed at which light is capable of traveling within that arbitrary, but defined, figure remains constant... Or does it?
Geordi La Forge well, in leap years light suddenly gets a whole other day to travel, which suddenly increases the distance of the lightyear. so even though the speed of light remains constant, the lightyear does not. now that's of course not how it works in science because it'd mes everything up, but that is what a lightyear is.
A year is the amount of time it takes for the earth to make a complete orbit around the sun. New year is arbitrary.
I didn't realize Crash Course had a chemistry video on unit conversions and when I found this I nearly started crying out of happiness. Unit conversions are very difficult for me.
I am fairly new to CrashCourse. I started watching last year for Anatomy and the body systems. I did really well because of CrashCourse. So, here I am, back again, thrilled to find Chemistry by CrashCourse! This was one of my favourites. Simply because of "...what we do to liars in Chemistry...". I laugh so much through the episodes my family wonder what is wrong with me!
Maybe an annotation is needed to correct the start of the video - the IPK no longer defines the kilogram, it is now defined as 6.0221408418x10^23 atoms of silicon-28 (Avogadro's Constant).
***** www.nist.gov/pml/si-redef/kg_new_silicon.cfm
am i the only one who to understand this has to wtach like 3 times.
then in slow motion. then backwards. then ask my father. then not understand and move to next episode?
What didn't you understand? Units or Significant Figures?
Yeah you sound like me. Keep trying though. Im persevering with Science and Maths because i have a genuine interest even though they make me feel like im thick..
You are not alone. But trust me, just paying attention in math, physics and chemistry in school, and some practice (homework), will make this a very simple subject. Everything is challenging at first.
Ask questions of what you don't understand, im sure a lot of people will be willing to help you.
Pause when you have to take something in which you know you won't understand just by quickly brushing past it. It helps me to write it down also for reference.
God, I wish you were my Science/ chemistry/ bio/ teacher. -_- OH you should do world tours. Not just in university's though. Like in high-schools and stuff.
And what you Americans call' idle school'!
Iffshah Jaffery Oh lol you mean middle school? That's grade 7 and 8 in Canada. :D I'm not American. :P AND he should do world-tours in America too YES
AquiredCents Yeah I've seen that show! It was amazing! It really made me think a lot about astronomy and whats really out there in the big wide universe.
Inayah Cee I'm British...
Iffshah Jaffery Yes but you said ' idle school' maybe you meant middle school but spelt it wrong. But I did not know you were British, I'm just saying that I'M not american. You said: "You Americans" :P
You set it up so nicely for a good chemistry pun! "You know what we do with liars in chemistry? We barium."
You made me love Chemistry. Thank you.
Please tell me someone else saw it at 5:30
+Colin Warn Took me some time, but yeah.
+Colin Warn thanks for the good laugh Colin!
( ͡° ͜ʖ ͡°)
Hah yep, I just opened the comments to see if anyone else did. 80085!
What did you see????
you explained more to me in 11 minutes then my chemistry professor did in 50 minutes, thank you so much.
I tried the physics course... the way she explains things put me off a little. The Green Bros (and Stan) are so much more clear, I don't know why.
I just wanted to say, I've been watching you SciShow for over a year now, and now since I just started honors Chem, it is so cool to actually learn school information for you. It is like you have moved from the entertainment part of my life to the school part, which is a really weird feeling. My chemistry class is already very interesting, but now my brain is processing it as raw entertainment. And for that I thank you.
Genuinely,
Paul Wyrough
It took 11 minutes for him to explain something that took my chemistry teacher 6 weeks to teach. ahh the wonders of the internet.
I know almost nothing about chemistry, I suck at math, and I did not find this episode - or any of the ones I have watched thus far - difficult to comprehend at all. Thank you. :)
Studying for the TEAS Exam for Nursing School. I haven't taken a Chemistry class since HS, about 10 years ago. Thanks for ALL your help!
how did hank go from 60 mph to 9.3 X 10^12 light years per second? I tried the math on my calculator, and I got 2.82485876 X 10^-15.
+Brian Lee so did I, I thought it was my error!!
Goddammit Hank. You know what we do to liars in chemistry, right?
so did I
I did as well. So annoyed cause I spent 15 minutes stressing about how to find the right answer. It really ISN'T as simple as "hammering" figures into a calculator!!
+Brian Lee
Most of the time, students enter the number into the calculator in the wrong order of operations. Use parentheses liberally.
I love crash course you guys are so dedicated to learning and you make learning really fun, thanks Hank and John :)
I am refreshing my brain with this videos, I find them Quite interesting. and like my dad always says , you have to learn twice , once you are a kid and second when you are a dad.
In the significant figures section he multiples 60 x 5.0839. He says that 60 is two significant numbers but isn't it only 1? Trailing zeroes are not significant. So that answer should be 3 x10^2 and not 3.0 x 10^2
Anyone else do Hank's process for turning 60 MPH into Light years/second and get a different answer than he did. I got 2.82e-15, anyone else?
"We kill them." I really never thought I would hear those words from Hank.
I thought this was the definition of a second: The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.
+arjenbij ... yes I'm so going to use that on my test
+arjenbij and the meter is defined as 1/299,792,458th of the distance light travels in a second (or the distance travelled in 1/299... seconds). Other definitions are still being worked on, though I believe two other constants are being based on planck length and the elementary charge.
I'm not sure of the exact count, but yes, time and distance have been defined by counts of the hyperfine state resonance in an inertial frame and the speed of light. Those might not be absolutely constant, but sure seem to be.
I didn't understand scientific notation or sig figs before this video, VERY HELPFUL!
There's the thing saying sorry about them messing up the number and stuff, then he proceeds to say, "And do you know what we do with liars in chemistry? We kill them". Hank, I'm sorry in advance for what's going to happen.
agree that km/h isnt much better, but it is easier to convert to lower units because of the standard base of si units(10). Converting miles to inches on the other hand, good luck.
Guys, don't be dismayed. The calculations seem to be wrong for some reason, as people said in previous comments. 60 m/h are equal to 2.8*10^-15 ly/s, because in the end you will be dividing 1 by 60*5.9 and multiplying the result by 10^-12, which in turn will leave you with a result of 0.0028*10^-12.
The difference between watching this at the first week of chemistry class and the 4th week of chemistry class is remarkable... Literally helping me study for my second test.
Had trouble figuring out how you calculated the conversion into light years.
same, can someone please explain?
okay got it he multiplied it but the answer is wrong it's supposed to be 2.84 x10^-12
Hi there, I got the same answer as you, except with 10^-15, even after I put the conversion through Google. Can you please confirm, or is there something important I'm missing? Thanks!
I got 2.82x10^-15 every time I did it also.
Same..I'm so lost
9:55 - I understand that we need to round to 2 sig figs in the final answer, but I thought you round the answer to 310 or 3.1x10^2? I thought you do that because the 5 in the ones place is right next to the 0 in the tens place, so you round up?
i swear this helped me so much more than a whole chem class period😭😭🙏tysm
Correct me if I am wrong, but at 10:00, I believe the actual number should be rounded up before the insignificant figures are omitted, which makes the number 3.1x10^ 2.
I still don't get it.
CRASH COURSE GEOMETRY AND ALGEBRA PLEASE!
Him: Uses calculator to calculate complex numbers...
Me, a CBSE student: What is this sorcery?
note to self: sigfig rules, also use scientific notation
do not include lying numbers!!
add/sub: number w fewest figures after decimal point decides how many decimal points should be there
mult: same number of sig figs as least number of sigfigs
use scientific notatuon to signify inaccuracies
50,000 - 100,000 people he says. 1.1 million there are... You modest person.
2.6mil
@@travisstroman-spaniel6091 3 mil now
Mom: What did you learn from the chemistry video today?
Me: Today we learnt that we kill liars in Chemistry!
60 mph = 0.000,000,000,000,002,82 ly/s Please correct me if i'm wrong. I hoped this help enjoy the playlist.
+RedExplosives I think you mean 0.0000000000000028 ly/s. Do not include any lying digits!
+David Guthary +RedExplosives I think you mean 28 x 10^-15.
+Angel Chupungco I think you mean 2.8 x 10^-15 ly/s.
+Angel Chupungco i think you mean 2,8 x 10^-15
+RedExplosives Can anyone help me? I did not get how he got 9.3x10^12 ly/s . Thanks in advance.
Wait, for the one where it says 60*5.0839, shouldn't the sig figs be 310? I learned that you have to round the sig figs. and you can keep it as 310 because the 0 is not significant unless it was .310 in which it becomes significant. If you wrote it in scientific notation it would be 3.1*10^-2
U guys should do videos on physics!!
what do we do with liars in chemistry........"WE KILL THEM".....
D then w barium (yeah I am sorry all the other good chemistry buns argon )
+crazysquirrel I hope these jokes don't come periodically
I slapped my neon that one. It was sodium funny
@@plantymcplantface7182 I hate all of you.
"you know what we do to liars in chemistry? we kill them" - Hank Green.
"Life is getting better comrades! Life is gett-" - Stalin dies
Hank Green: Life, like everything is science and chemistry
This video helped me pass a science test. God bless. Videos like this are the reason i dont have to pay attention in class.
Maybe is my brain fault, but I can not calculate9.3*10^-12 at 5:02. I only got 2.82*10^-15
Same.
"You know what we do to liars in chemistry... We kill them" OMG I DIED
I assume you are a liar?
who else is watching this for homework right now
I love that he opened with the often overlooked fact that units of measurement are completely arbitrary. Got my attention right away. I've never understood significant figures before today, and now it makes perfect sense! Thank you!
"And you know what we do to liars in chemistry? We kill them."
Suddenly I'm not as interested in chemistry.
So Hank, fun fact from my engineering lab. You had a little apology at the top near the end for rounding the 5 down, but that is actually correct for scientific rounding. Scientific rounding is set up so that if the preceding number is even, you round down so its stays even, and if it is odd, you round up so it is then even. It is different from "Normal" rounding because, statistically, it should produce just as many round ups as it does round downs instead of causing a slight inflation. Since this video is for chemistry, scientific rounding would be correct and the math done in the video is thus correct as well.
其实五后面还有非零数字，应该进一，感觉视频错了
Google Translate: In fact, there are nonzero digits after five，should Rounding up to one. I think the calculation in the video is wrong.
WOw your crash course of chemistry is very useful for me... thanks Crank.
I love how these videos are so helpful and relevant years down the road
In your multiplication example, wouldn't the 305 rounded to 2 S.F. be 310 not 300? the 5 makes the tens digit 1?
Joe Wong They corrected that in the annotations.
Joe Wong If I am not mistaken, the 6 is the only sig fig in the number 60, since no decimal point is present. Trailing zeros are only counted as significant figures if and ONLY IF a decimal point is present. If the number was 60. then there would be 2 sig figs in the number, or 60.0 would be 3 sig figs, and so on. However there is no decimal point in the example shown in the video. That makes the least amount of significant figures only 1, so the original 300 is correct.
Jennifer Stephens Actually, it's even worse than that: You need to know the resolution and fault margin of the measuring device. The speedometer in a car in Europe, and I guess in the US too is deemed OK when the real value is between -12% and 0% of the measured value, with standard tyres (new tyres inflated to rated pressure and nominal temperature)... This means if your speedo says 60 MPH, you can be driving between 52 and 60 MPH, which would mean that there is not a single SF valid. So in the end the Speedometer isn't a measuring device but a guessing instrument.(In a truck in Europe, the speedo is regularly calibrated, but tyre -wear and -inflation may be used to cheat a bit)Your GPS system is more accurate, and there I would dare to keep 2 or 3 SF's valid.
In this case, to come back to the O.P., 305.00* would indeed be noted as 3.1*10²
60 only has one significant figure and hence should be written as 6*10(exp)1
Hi. just a guy from the future (it ain't pretty). just came by to say that the first conversion was incorrect the correct answer was 2.81x10^-15 ly/s for me
myself and my college pro love your videos.
we discuss almost weekly in class about you and how you make it easier to learn
or how what we are doing in class relates to what we have seen on crash course !
i encourage my class mates to also watch these videos
hank: and do you know what we do with liars in chemistry?
me: *anticipating some nerdy chemistry pun*
hank: we kill them
A Physics series please
And a math series please
0:08 sir what did you expect from a battery when you thouch that with your tongue
wow, so it’s really THIS easy?! my professor made this sound like a foreign language!!! thank you
All the dislikes are the people who use the imperial system
No we barium
I'm gonna need you to take over for my current chemistry teacher. Lol
Hank, you're the GOAT. Please don't ever stop posting these videos
at the end i thought he'd make some sort of joke or pun about the whole thing, or try something clever, and then just "we kill them"
idk, maybe cause i've had no sleep, but im dying XD
"Im dying"
Is it cause ur a liar?:)
lol xD
5x5=30
4x4=20
6x6=40
7x7=50
8x8=60
9x9=80.
Poor 70, you don't exist.
*****
3x3=10
2x2=0=1x1
***** Sorry but no. The initial numbers are accurate down to the one's place. Because of this, the result will also be accurate down to the ones place. Having the result be an order of magnitude higher does not change this.
Harlan Kempf Hey, it was just a joke, don't you know how to round off figures in math?
Shubham Thakkar His point is that his calculations were valid, but yours were not.
I
The editing,the music,the teaching and all these stuff are amazing and i just love them 😄
While I do understand that significant figures are awesome and necessary, I do find them a bit tedious sometimes. For instance, if I want the mass of a water molecule, I can refer to my high school periodic table. It tells me that oxygen weighs 15.999 g/mol and hydrogen weighs 1.0079 g/mol. I understand that both numbers have the same number of significant figures, which is very important, however it can trick me into thinking that they must have weighed the hydrogen with a more accurate tool (which in scientific research is a cardinal sin), when in reality they're just obeying the laws of significant figures.
Sincerely,
A forgetful chemist.
I have a physics teacher named Watt..
'What is a unit of energy?'
'What, sir?'
'Correct'
FROP DESAI ‘What is the unit of energy?'
'Thank you, sir.''
FROP DESAI Wow!! Ur really,seriously! U should have a utube channel based on that...or at mainly that.(unless that's the same thing)? :-)
Milo curry sorry I meant ur good
Milo curry
Thanks! I was going to start a proper RUclips channel. Great to know that I can make someone smile for at least a few seconds.
5:19 wow that was like a 98% percent error.
Sig figs in calculations finally clicked for me after watching this. The way the textbook was describing it was just not working for me, and this video provided the connections that I was struggling to make on my own. 10/10
But do you barium?
HAHAHAHA as I am fussing with Calculator you called me on it
I love how Hank thinks there will only be around 50 to 100 thousand people who will have watched this video. Come on Mr Hank-Smarty-Pants :)
He meant the people that take out calculators, 7 would ask why he cut off or estimated the decimal place.
as soon as he said that i checked, lol, there was .5 x 10 ^ 6.
Crash course has literally everything that I need! Thank you!