We made quiz questions 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/3TW06aP
Wuuuuuuuuuuuut! I had no idea about those cracks being because of expansion and contraction. That's slick. Learn something new like 10 seconds into a video. New record?
Heres a question that sometimes racks my brain, when you're moving forward in a car and a fly comes in the window does it have to fly forward as fast as the car? or is the air in the car pushing the fly so it just has to maintain it's hover?
If the fly is entering the car from behind, it needs to fly faster than the car to reach it and enter the window. But once inside, the air inside the car moves at the same speed as the car, so it only needs to hover in the air to follow the car.
great job with the colorcoding of the variables, great job explaining everything and also great work doing a short video with A LOT of content. wins a sub in need for more.
Small k for Kelvin, a small error. And it might have been nice to mention the microscopic version of the ideal gas law as well. Boltzmann constant has a few more uses than the ideal gas constant. But you can't squeeze in everything in 9 minutes. Maybe there will be a statistical physics lecture in the future ;)
In college, the way I remembered PV=nRT is that it sounds like saying "pervert" with your nose plugged. Not that I was called pervert at college... well, not every day.
My favourite statement of the ideal gas law: P = N kT N being the number density (inverse volume units) and k Boltzmann's constant. I like it because it shows pressure being like an energy density and like a momentum density.
Love this series, it needs more praise by the fans. It's a shame most of the fans are just here for Hank and John. I love every series regardless the host and especially this one.
So, wait. At 4:30 you said as Temperature increases volume increases. Yet in the car example, the car has less moles when it is hotter? Moles equates to density right? So, I guess in that sense if mass is constant then higher density means lower volume. So I guess that would make sense. Do I have the right idea?
"Moles" are the "amount of atoms" inside the car. So as the gas warms up, the density decrease, and a lower amount of gas atoms (moles) can cover the entire inside (volume) of the car. So a warmer car has a lower amount (and mass) of air inside it, because the hot air has expanded and some of it has left the car.
crazy thing about temperature: a single particle can not have a temperature, there needs to be multiple particles/molecules/things moving around and bumping into eachother
It contracts in cooler weather so the metal thing in the bridge gets further so it will fall appart because it's going further apart so the bridge will fall
One problem: if linear expansion of a solid is a(l_0)(∆T) and the area of the cross-section perpendicular to length has no reason to be fixed/to not follow the square of this equation, why isn't expansion of a solid V_0[(a)(∆T)]^3? Or if the volumetric expansion equation is accurately given, shouldn't linear expansion be l_0[(b)(∆T)]^(1/3)?
I can't listen to this while the Dingmans Ferry Bridge is stuck in my head. I can hear it, but the words aren't connecting, because the bridge they're describing is a fantasy.
SECOND QUESTION. So, in the final example, if the car _was_ airtight, would that mean that the temperature inside couldn't change? That can't be right can it- the radiation should still give energy to the molecules inside. So then, does the constraint of Pinside = Poutside no longer hold true? Or, would the volume expand?
The Linear expansion of a steel beam. (alpha)=(13x10^-6)/*C, (length)=3.66 metres, Temperature (of burning jet fuel)=1500*C. (delta) L = (13x10^6/*C)(1500*C)(3.66m) = 7 cm. This means a 540 metre (54'000 cm/138 story) building has 14'754 steel beams. If 20 stories (78 metres) are on fire that is 21.3 steel beams exposed to that temperature. That means each beam is now 3.73 metres by individual linear expansion. Multiply 3.73 metres by the 21.3 steel beams, and find a total linear expansion of 79.5 metres. That is a difference of 1 meter using linear expansion.
Confused vocabulary: [01:01] "Kinetic energy...of a system" is usually its systemic velocity, and in fact even atomic kinetic energy in solids and liquids is due to interchanging electron orbital radii, not to the energies of those radii... [02:58] Why is Δvol. linear instead of cubic, with respect to Δtemp., and what-about 2D areal expansion such as of unconstrained tar...
To clarify the interchanging electron orbital radii, are not atomic '12345spdf' jumps 'til ionizing temperatures, but rather that nuclei/protons slow moving, massage the quantum band tunings continually where Saha's formulation applies significantly...
Based upon the equations, it appears that exactly the same amount of energy is required to increase any given substance or system by one degree in temperature. Which makes perfect sense, but it gets to seem a bit crazy when scaled up or down, so I'd like to get some clarification, if someone would be so kind. Given the amount of energy required to increase a kilogram of water by 1 degree celsius (1 kilocalorie, or 1 [large] Calorie), does that mean the same amount of energy will also increase a single gram of water by 1000 degrees celsius? (Barring a phase change, of course, which will change the specific heat of the substance. Assume ideal superheating, a perfectly closed system, etc.)
Basically, yes. But when you start to actually get that kind of heat, all kinds of other effects start to apply. When you reach 100C, you have to spend a lot of energy on the phase change to gas. And once you are a gas, the same amount of energy do not increase the temperate the same amount as in the liquid (or solid) phase. The amount of energy required to increase the temperature by one degree also change slightly based on temperature within a phase, but this is mostly relevant for ridiculusly warm vapor. This concept is usually refered to as "Heat capacity" for the matter you are warming, in case you want to research it further.
Actually that is not correct specific heat capacities vary between materials, that is the amount of energy required to produce a given change in temperature in a given mass of the substance usually expressed in terms of J/K·g ie the amount of energy in Joules required to increase the temperature of 1 gram of the substance by 1 Kelvin. For water the value is 4.184 J/K·g, copper on the other hand has a specific heat capacity of 0.385 J/K·g. Thus water can actually absorb nearly 10.9 times the energy per unit mass than copper for the same change in temperature, the effect is of course somewhat smaller per unit volume since copper is 8.96 times the density of water but still it's 1.21 times the heat energy per unit volume. Course how fast different materials actually heat up in practice depends on a whole host of other factors too for direct heat transfers mostly that would be the thermal conductivity though for fluids even the shape of the container or basin can be a factor due to the effects of fluid dynamics and convection. Things get even more complex when dealing with radiative transfers which is especially tricky when dealing with expansion in outdoor structure since of course the primary heat source (the Sun) is a radiative transfer and properties like reflectivity, emissivity and absorbtion can be affected by factors as basic as what colour paint you put on a material.
I have a question about temperature Shini. I can see how holding an open flame to your hand will burn your hand because the air molecules are moving so quickly that they will destroy your cells on impact. My question is how dose something like liquid oxygen immediately freeze your hand when there is very little kinetic energy in the liquid oxygen to react with your hand?
If two objects are touching, the rate of heat transfer between them is proportional to the difference in temperature. In the flame scenario, the molecules don't destroy your cells on impact (that would be something like alpha radiation), they just bounce off them and give them kinetic energy. The energy then tries to go somewhere, like up your arm or out the back of your hand, but it can't move faster than the flame is pumping in new energy, so the energy builds up in your hand, which destroys the cells. With liquid oxygen, it's the opposite, your hand is the flame. The temperature difference is still really large though, so the kinetic energy is violently sucked out of your hand molecules, until the water molecules get slow enough that they start sticking to each other (freezing). When water freezes it makes really bulky, sharp-edged crystals, which rip apart the cells they form in.
+Frank Schneider Just let you know, they "make" these videos a few months in advance. If you were joking then hardy har har what a good laugh. Ps. This is not to be a hate comment, have a great day
How can the pressure remain constant with an increase in pressure in the car analogy given at the end? And how can number of moles of gas change in the airtight car? Sorry if I'm being dumb, and thanks in advance :)
Your concept and materials are strong...but videos are going too fast to understand even at 0.75*speed ... Thanks for providing us so much knowledge and concepts used in daily life..which matters and also important... But kindly make the complete videos on these topics so that we will understand even more from it And it helps a learning student a lot... Thanks again ...
There are 11 moles of air less in the afternoon because of the higher temperature. Are we assuming that at some point between the morning and afternoon, a door was opened to allow an exchange of air with the outside? If the cabin is airtight and a door was never opened, then I can't see how there could be less moles in the afternoon.
I'm no expert but I think there's a slight problem with the explanation of the temperature increasing the volume. In the example, the gas was in a balloon (called a container) and it was said that increasing the temperature means making the molecules move faster, thus pushing out the container. However, it was stated earlier that one of the assumptions of an ideal gas is that its volume is much less than that of the container. This raises the question, are we talking about the volume of the gas, or of the container?
Ohhh, I didn't see the video, but either you heard something wrong or they said something horribly wrong. One of the fundamental properties of gases is that they take up all the volume available to them. If you put a gas in a container, it will have the volume of the container, no matter what.
hmmm, as I understood, the two expansion equations doesn't have sense when are considered together: \Delta l = \alpha l_0 \Delta T \Delta V = \beta V_0 \Delta T if the solid is a cube, then V=l^3, and as \Delta l = l-l_0 then l=l_0+\Delta l, so V=(l_0+\Delta l)^3=(l_0+\alpha l_0 \Delta T)^3 but also V=V_0+\Delta V=V_0+\beta V_0 \Delta T then (l_0+\alpha l_0 \Delta T)^3=V_0+\beta V_0 \Delta T If we expand, one side of the equation would have \Delta T^3 and the other one would have \Delta T, if we vary \Delta T but we let constant the rest it would be like saying that a polynomial of degree 3 is equal to a polynomial of degree 1.
wouldn't it have been easier to say that heat expansion has to do with the electron movements (heat) and that the expansion has to do with how high the electrons in an atom jump around, or would that be incorrect?
Yes! A teacher used avocados as an example. 6.02 x 10^23 avocados can make how much guacamole? It was weird, but it makes enough for 3.612 x 10^24 people...
Hydrogen bonds :) the hydrogen atoms are more positif and the oxigen atoms are negative. when it is cold enough, the H2O molecules are moving less so that the molecules can attract eachother and form crystals. those crystals are less dense then liquid water because there is more space between the molecules, so the fluid expands
I actually think that a more useful version of the ideal gas law to teach would be P=DRT, where D is density. I think that the relationships in-between the three variables are easier to understand and explain in this form. Then, you can explain that becuase D=n/V, you can get PV=nRT.
To clarify, what you're describing could be considered to be a "molar density". Not to be confused with D=m/V, where m is mass. Can't tell if you've accounted for that or not but I want to draw that distinction first. What you described I think would mathematically work for the ideal gas law. In practice however, just going off of what I remember from general chemistry, the relationships described in the formula in the video are more readily understood conceptually. I'm not the most educated on this topic though, maybe a chemist, physicist, or just somebody more familiar with the topic has a different opinion.
I looked online, and apparently the formula for something like this is actually PM = dRT, where M is the molar mass and d=m/V. So you were right about it being a molar density. :)
That was the Tacoma Narrows Bridge in Washington state. It collapsed a few months after it opened in 1940. The wind made the bridge oscillate wildly and fall apart before engineers knew to calculate for aeroelastic flutter.
PV=nRT works regardless of the fact that air is composed of many different Molecules? I mean, 1 mol of Oxygen at atmospheric pressure occupies another volume than 1 mol of Nitrogen or 1 mol of CO2 do at the same pressure, right? Isn't the calculation kinda flawed for mixed gasses?
No, because there is so much space between gasses at low temperature and pressure (not in a hot compressed gas) that all gas molecules are roughly the same shape and size as each other compared to the gas around them
Isn't linear expansion the same as volume expansion? Because a metal bar as it heats up will get larger, but will also become thicker. But the change in thickness is just irrelevant in relation to the change in length. Did I understood something wrong?
Its a good point - you're on to something. In addition to getting longer, the bar may indeed get "thicker" as well and depending on what you want the shape to do or what you permit the shape to do, say for engineering purposes, this change in thickness may be too big and cause trouble. Think of a shim in between two other shims, the middle shim is getting more compressed by the outer shims like a sandwich as it gets heated and gets "thicker" - the outer shims push back! Will it break and cause a bridge collapse? Thats what you will know how to answer if you take engineering and get paid for it to boot :) As a more complete answer, the precise change of dimensions (call it dx,dy,dz) of any arbitrary shape at any point on the shape due to a temperature change is explained by more complete equations that not only consider the coefficient of linear thermal expansion in three dimensions (x,y,z) but also consider Poissons Ratio, Youngs Modulus and Shear Modulus for that material - I cant remember if theres any other properties you'd need, its been a while. Could there be a way to combine all these properties to get some "volume" coefficient of thermal expansion or has someone done experiments to find a volume thermal expansion for different solids? Probably. Or perhaps an alternate method like distortion energy could be used to determine the dimension changes. If all else fails, use computer simulations lol
We made quiz questions 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/3TW06aP
went from music physics to thermodynamics in one episode. that escalated quickly xD
I love this videos, especially how you use animations to visualize the equations. I hope there will be more about thermodynamics.
I simply LOVE to see this woman explain physics! She makes it even MORE fun to appreciate.
That sexist
+Luis Rodriguez
No, it isn't.
Such a brilliant platform!
Great video! And you reminded me that Avogadro's number is 6.022 x 10^23!
Wuuuuuuuuuuuut! I had no idea about those cracks being because of expansion and contraction. That's slick. Learn something new like 10 seconds into a video. New record?
No. It took your age, plus 10 seconds.
Thank you for helping humanity learn about their home and laws that governs it.... 👍😁
Love it!
Thank you CrashCourse, keep'em coming.
3:36 I heard "Hank Hoes did" instead of "Hank hosted" I'm dying rofl
I love this physic teacher 😍 !
yeah shes pretty hot
Yup, she's super cool and hot! And i love her accent!
Heres a question that sometimes racks my brain, when you're moving forward in a car and a fly comes in the window does it have to fly forward as fast as the car? or is the air in the car pushing the fly so it just has to maintain it's hover?
If the fly is entering the car from behind, it needs to fly faster than the car to reach it and enter the window. But once inside, the air inside the car moves at the same speed as the car, so it only needs to hover in the air to follow the car.
214 moles in your car? Someone call the exterminator
Crota son of Oryx 😑😐Lame my friend. ..just lame
I have no regrets
NO REGRETS
lol
I laughed
DO CRASH COURSE MATHEMATICS
The World Is Logic YEAH!
@@garnet4945 The World is Corona YEAH!
I blame my afternoon drowsiness on that 5.2% less air
great job with the colorcoding of the variables, great job explaining everything and also great work doing a short video with A LOT of content. wins a sub in need for more.
Small k for Kelvin, a small error. And it might have been nice to mention the microscopic version of the ideal gas law as well. Boltzmann constant has a few more uses than the ideal gas constant. But you can't squeeze in everything in 9 minutes. Maybe there will be a statistical physics lecture in the future ;)
Kelvin is big K
This channel is simply perfect... I can improve my english and review physics at the same time🧠❤️
In college, the way I remembered PV=nRT is that it sounds like saying "pervert" with your nose plugged.
Not that I was called pervert at college... well, not every day.
High school chem teacher taught it as perverted nerds. Lmao.
yea
You could also just learn why it's true lol
Thank you for the help!
This is literally one semester worth of applied physics compressed in 9 minutes (yesterday at school we saw ideal gases)
An episode on Temperature.......So cool!!!
Thanks for doing these videos. I really appreciate them. 😊
Thank you to help us. I also use Giancoli's book at the training teacher college.
My favourite statement of the ideal gas law:
P = N kT
N being the number density (inverse volume units) and k Boltzmann's constant.
I like it because it shows pressure being like an energy density and like a momentum density.
New Seating Position?
4:16
i was wondering where the constants where at but it was behind the subtitles... lol
Love this series, it needs more praise by the fans. It's a shame most of the fans are just here for Hank and John. I love every series regardless the host and especially this one.
I was a big fan of Phil Plait and Astronomy too, I've liked his views on Nova and the like too
Hank brings more humor, imo. Shini just looks overly excited.
I wish she could speak a little more calm to let my brain absorb and process what she is saying.
its a crash course for a reason actually.
Then slow it down
@@aakashSky-0 breathing for a second doesn't make it long...
GOOD TEACHING
So, wait. At 4:30 you said as Temperature increases volume increases. Yet in the car example, the car has less moles when it is hotter? Moles equates to density right? So, I guess in that sense if mass is constant then higher density means lower volume. So I guess that would make sense. Do I have the right idea?
"Moles" are the "amount of atoms" inside the car.
So as the gas warms up, the density decrease, and a lower amount of gas atoms (moles) can cover the entire inside (volume) of the car.
So a warmer car has a lower amount (and mass) of air inside it, because the hot air has expanded and some of it has left the car.
could you please explain electrostatics, capacitor,current.... in detail?
crazy thing about temperature: a single particle can not have a temperature, there needs to be multiple particles/molecules/things moving around and bumping into eachother
5:27 okay but in the video on heat, the formula is given as pv=nrt(3/2)
Well put
how to describe how much great it was? I have no words for that
It contracts in cooler weather so the metal thing in the bridge gets further so it will fall appart because it's going further apart so the bridge will fall
Temperature
Thermal expansion
Linear and volume expansion
Ideal gas law
Number of moles of air
Great Turorial
5.2% less air! Oh no!
I'm talking about 20º C of course
Overwatch ARG at 6:20??
One problem: if linear expansion of a solid is a(l_0)(∆T) and the area of the cross-section perpendicular to length has no reason to be fixed/to not follow the square of this equation, why isn't expansion of a solid V_0[(a)(∆T)]^3? Or if the volumetric expansion equation is accurately given, shouldn't linear expansion be l_0[(b)(∆T)]^(1/3)?
I can't listen to this while the Dingmans Ferry Bridge is stuck in my head. I can hear it, but the words aren't connecting, because the bridge they're describing is a fantasy.
SECOND QUESTION. So, in the final example, if the car _was_ airtight, would that mean that the temperature inside couldn't change? That can't be right can it- the radiation should still give energy to the molecules inside. So then, does the constraint of Pinside = Poutside no longer hold true? Or, would the volume expand?
Once again she's breaking the traffic rules, an equation I can't figure out with physics. 😱😱😏
if this is how teachers are like outside of where i live then i hate this place
Love your films
Dr. Somara, what is your favorite bridge?
your mom!!!! (hi)
hi!
London bridge
really cool vid
If anyone was wondering the bridge in the video at the start was moving like that because the wind caused it to vibrate at its resonant frequency.
You guys need to do crash course CLIMATE CHANGE!
The Linear expansion of a steel beam. (alpha)=(13x10^-6)/*C, (length)=3.66 metres, Temperature (of burning jet fuel)=1500*C.
(delta) L = (13x10^6/*C)(1500*C)(3.66m) = 7 cm.
This means a 540 metre (54'000 cm/138 story) building has 14'754 steel beams. If 20 stories (78 metres) are on fire that is 21.3 steel beams exposed to that temperature. That means each beam is now 3.73 metres by individual linear expansion. Multiply 3.73 metres by the 21.3 steel beams, and find a total linear expansion of 79.5 metres. That is a difference of 1 meter using linear expansion.
Confused vocabulary: [01:01] "Kinetic energy...of a system" is usually its systemic velocity, and in fact even atomic kinetic energy in solids and liquids is due to interchanging electron orbital radii, not to the energies of those radii... [02:58] Why is Δvol. linear instead of cubic, with respect to Δtemp., and what-about 2D areal expansion such as of unconstrained tar...
To clarify the interchanging electron orbital radii, are not atomic '12345spdf' jumps 'til ionizing temperatures, but rather that nuclei/protons slow moving, massage the quantum band tunings continually where Saha's formulation applies significantly...
Based upon the equations, it appears that exactly the same amount of energy is required to increase any given substance or system by one degree in temperature. Which makes perfect sense, but it gets to seem a bit crazy when scaled up or down, so I'd like to get some clarification, if someone would be so kind.
Given the amount of energy required to increase a kilogram of water by 1 degree celsius (1 kilocalorie, or 1 [large] Calorie), does that mean the same amount of energy will also increase a single gram of water by 1000 degrees celsius? (Barring a phase change, of course, which will change the specific heat of the substance. Assume ideal superheating, a perfectly closed system, etc.)
Basically, yes.
But when you start to actually get that kind of heat, all kinds of other effects start to apply. When you reach 100C, you have to spend a lot of energy on the phase change to gas. And once you are a gas, the same amount of energy do not increase the temperate the same amount as in the liquid (or solid) phase. The amount of energy required to increase the temperature by one degree also change slightly based on temperature within a phase, but this is mostly relevant for ridiculusly warm vapor.
This concept is usually refered to as "Heat capacity" for the matter you are warming, in case you want to research it further.
Thank you for the clarification. I suspected as much but it does seem quite outside of what one would expect, in such extreme circumstances.
Actually that is not correct specific heat capacities vary between materials, that is the amount of energy required to produce a given change in temperature in a given mass of the substance usually expressed in terms of J/K·g ie the amount of energy in Joules required to increase the temperature of 1 gram of the substance by 1 Kelvin. For water the value is 4.184 J/K·g, copper on the other hand has a specific heat capacity of 0.385 J/K·g. Thus water can actually absorb nearly 10.9 times the energy per unit mass than copper for the same change in temperature, the effect is of course somewhat smaller per unit volume since copper is 8.96 times the density of water but still it's 1.21 times the heat energy per unit volume.
Course how fast different materials actually heat up in practice depends on a whole host of other factors too for direct heat transfers mostly that would be the thermal conductivity though for fluids even the shape of the container or basin can be a factor due to the effects of fluid dynamics and convection. Things get even more complex when dealing with radiative transfers which is especially tricky when dealing with expansion in outdoor structure since of course the primary heat source (the Sun) is a radiative transfer and properties like reflectivity, emissivity and absorbtion can be affected by factors as basic as what colour paint you put on a material.
I see that symmetra spray at 6:33
Is that an Overwatch Hover Car at 6:21?
I love your videos please make more, you rock
Echo reduction material needs to be adjusted to compensate for Dr. Shini's new position/set.
2:53, Symmetra? Is that you?
I have a question about temperature Shini. I can see how holding an open flame to your hand will burn your hand because the air molecules are moving so quickly that they will destroy your cells on impact. My question is how dose something like liquid oxygen immediately freeze your hand when there is very little kinetic energy in the liquid oxygen to react with your hand?
If two objects are touching, the rate of heat transfer between them is proportional to the difference in temperature. In the flame scenario, the molecules don't destroy your cells on impact (that would be something like alpha radiation), they just bounce off them and give them kinetic energy. The energy then tries to go somewhere, like up your arm or out the back of your hand, but it can't move faster than the flame is pumping in new energy, so the energy builds up in your hand, which destroys the cells.
With liquid oxygen, it's the opposite, your hand is the flame. The temperature difference is still really large though, so the kinetic energy is violently sucked out of your hand molecules, until the water molecules get slow enough that they start sticking to each other (freezing). When water freezes it makes really bulky, sharp-edged crystals, which rip apart the cells they form in.
Thanks Rhaegar19.
Un dos tres Calipso
Un dos tres Calipso
Sing whit me !
Calipsooo
cool (sorry for my bad English)
Bruh, you literally just said one word dawg.
1:39 is it applicable for all objects around?
PV=nRT, the only formula I remember from my chemistry and will likely never forget. lol
way over my head. but I love it.
where did the table go?
sold to pay the bills because of not enough viewers.
Hmm, I wonder when the host will be auctioned off.
+Frank Schneider Just let you know, they "make" these videos a few months in advance. If you were joking then hardy har har what a good laugh.
Ps. This is not to be a hate comment, have a great day
Nice!
What about water it expands and contracts with temperature until it gets down to 4°C where it no longer contracts
How can the pressure remain constant with an increase in pressure in the car analogy given at the end? And how can number of moles of gas change in the airtight car?
Sorry if I'm being dumb, and thanks in advance :)
Your concept and materials are strong...but videos are going too fast to understand even at 0.75*speed ...
Thanks for providing us so much knowledge and concepts used in daily life..which matters and also important...
But kindly make the complete videos on these topics so that we will understand even more from it
And it helps a learning student a lot...
Thanks again
...
There are 11 moles of air less in the afternoon because of the higher temperature. Are we assuming that at some point between the morning and afternoon, a door was opened to allow an exchange of air with the outside? If the cabin is airtight and a door was never opened, then I can't see how there could be less moles in the afternoon.
Good point. Luckily, she specifically said that the car was not airtight.
I'm no expert but I think there's a slight problem with the explanation of the temperature increasing the volume. In the example, the gas was in a balloon (called a container) and it was said that increasing the temperature means making the molecules move faster, thus pushing out the container.
However, it was stated earlier that one of the assumptions of an ideal gas is that its volume is much less than that of the container. This raises the question, are we talking about the volume of the gas, or of the container?
Ohhh, I didn't see the video, but either you heard something wrong or they said something horribly wrong. One of the fundamental properties of gases is that they take up all the volume available to them. If you put a gas in a container, it will have the volume of the container, no matter what.
Wait what? 1:36 isn't it the other way? when it gets cold it expand??
Nope
5:34 Gay-Lussac's Law PV=nRT =.=
lol I went to Google maps to see if these expansion gaps exist, and I then found that I am continuing to watch the video a few weeks later.
charles' law-boyle's law
brooklyn 99 fans ayyy
hmmm, as I understood, the two expansion equations doesn't have sense when are considered together:
\Delta l = \alpha l_0 \Delta T
\Delta V = \beta V_0 \Delta T
if the solid is a cube, then V=l^3, and as \Delta l = l-l_0 then l=l_0+\Delta l, so
V=(l_0+\Delta l)^3=(l_0+\alpha l_0 \Delta T)^3
but also
V=V_0+\Delta V=V_0+\beta V_0 \Delta T
then
(l_0+\alpha l_0 \Delta T)^3=V_0+\beta V_0 \Delta T
If we expand, one side of the equation would have \Delta T^3 and the other one would have \Delta T, if we vary \Delta T but we let constant the rest it would be like saying that a polynomial of degree 3 is equal to a polynomial of degree 1.
ya whoop whoop
wouldn't it have been easier to say that heat expansion has to do with the electron movements (heat) and that the expansion has to do with how high the electrons in an atom jump around, or would that be incorrect?
You guys haven't put this in the physics playlist yet.
THIS...helped in soo many ways for my finals. Thank You :)
You guys should refer 6.02*10^23 as avagadros number bc it is far easier to remember
I agree, but remember these videos are addressed to audiences who may not have a prior knowledge in chemistry such as what Avogadro's Number is.
nerd!!!!!
*Avogadro
Yes! A teacher used avocados as an example. 6.02 x 10^23 avocados can make how much guacamole? It was weird, but it makes enough for 3.612 x 10^24 people...
The Rubik's cube has finally solved!!!!
Wow you gorgeous...I couldn't hear the words, their meaning, to be precise. Not fair, I came to learn!
i just leanded about those cracks at school
what is the name of those 4 physics books on the top of stacked Feynman books?
When i learned it we used alpha for linear, gamma for volume and beta for area. Why would you skip area?
video length ? It is also pretty obvious to interpolate, isn't it ?
Do crash course sociology please!
shout out to the physics for scientist and engineers Giancoli textbook in the back there.
Can you explain why a soda can expands in a freezer or cold environment when you explain that the colder the temp, the smaller it should be.
Water is a weird exception to that rule because it forms really bulky crystals when it freezes. It starts expanding below 4C.
Hydrogen bonds :)
the hydrogen atoms are more positif and the oxigen atoms are negative.
when it is cold enough, the H2O molecules are moving less so that the molecules can attract eachother and form crystals. those crystals are less dense then liquid water because there is more space between the molecules, so the fluid expands
I actually think that a more useful version of the ideal gas law to teach would be P=DRT, where D is density. I think that the relationships in-between the three variables are easier to understand and explain in this form. Then, you can explain that becuase D=n/V, you can get PV=nRT.
To clarify, what you're describing could be considered to be a "molar density". Not to be confused with D=m/V, where m is mass. Can't tell if you've accounted for that or not but I want to draw that distinction first. What you described I think would mathematically work for the ideal gas law. In practice however, just going off of what I remember from general chemistry, the relationships described in the formula in the video are more readily understood conceptually. I'm not the most educated on this topic though, maybe a chemist, physicist, or just somebody more familiar with the topic has a different opinion.
I looked online, and apparently the formula for something like this is actually PM = dRT, where M is the molar mass and d=m/V. So you were right about it being a molar density. :)
I was wondering when Avogadro's number would make an appearance in this series. Surprised yall didn't call it by name.
where was 0:09 taken from?
That was the Tacoma Narrows Bridge in Washington state. It collapsed a few months after it opened in 1940. The wind made the bridge oscillate wildly and fall apart before engineers knew to calculate for aeroelastic flutter.
PV=nRT works regardless of the fact that air is composed of many different Molecules? I mean, 1 mol of Oxygen at atmospheric pressure occupies another volume than 1 mol of Nitrogen or 1 mol of CO2 do at the same pressure, right? Isn't the calculation kinda flawed for mixed gasses?
And thats why its ideal friend
Beefyhax
I'm a derp, thanks xD
No, because there is so much space between gasses at low temperature and pressure (not in a hot compressed gas) that all gas molecules are roughly the same shape and size as each other compared to the gas around them
Alex Tritt
So there is an other more complicated formula than the one mentioned above for higher temperature and pressure?
+Yunnik yes there is... I forgot exactly what it was though. There were like 2 other properties based on the particular gas that were included.
Isn't linear expansion the same as volume expansion? Because a metal bar as it heats up will get larger, but will also become thicker. But the change in thickness is just irrelevant in relation to the change in length. Did I understood something wrong?
Its a good point - you're on to something. In addition to getting longer, the bar may indeed get "thicker" as well and depending on what you want the shape to do or what you permit the shape to do, say for engineering purposes, this change in thickness may be too big and cause trouble. Think of a shim in between two other shims, the middle shim is getting more compressed by the outer shims like a sandwich as it gets heated and gets "thicker" - the outer shims push back! Will it break and cause a bridge collapse? Thats what you will know how to answer if you take engineering and get paid for it to boot :)
As a more complete answer, the precise change of dimensions (call it dx,dy,dz) of any arbitrary shape at any point on the shape due to a temperature change is explained by more complete equations that not only consider the coefficient of linear thermal expansion in three dimensions (x,y,z) but also consider Poissons Ratio, Youngs Modulus and Shear Modulus for that material - I cant remember if theres any other properties you'd need, its been a while. Could there be a way to combine all these properties to get some "volume" coefficient of thermal expansion or has someone done experiments to find a volume thermal expansion for different solids? Probably. Or perhaps an alternate method like distortion energy could be used to determine the dimension changes. If all else fails, use computer simulations lol
Stephen Hawking read by Micheal Jackson? "Hee, hee, little black holes, jamoni"
in the final example, won't the pressure decrease when temperature decreases and the ratio will be the same ???
Can I get thermal properties of metirial *11th
OMFG!!! There were over 6 kg of air in that car in the morning. I can’t believe it.
I wonder if there will be crash course mathematics, that could be interesting.
They should have a radiometer on set