They look tasty but I wouldn't eat it with the phenolphthalein. Agar is edible though, you can buy it in stores, it's used as a thickening agent. Phenolphthalein will make you sick if you eat it.
Hi, I just wanted to thank you for this video. Not only did you explain the topic very well, but you did it in a context that actually made me very happy to learn. This is something my teacher failed, and I just want to say how much I appreciate it because it means that I can actually enjoy studying this as I can see how it is with actual examples which interest me, instead of a boring flat and arbitrary experiment.
You're exactly right. Without context, information that teachers throw at you is somewhat meaningless and not very interesting. I love how this guy so much enthusiasm and really enjoys what he is teaching, that quality in a teacher is worth paying for.
One of the best videos explaining this topic of surface area and volume. The phenolphthaleine analogy was amazing, made it very easy to visualize the process of diffusion and the importance of surface area to volume ratio. And the applicability of this concept in real life made the video even more enjoyable and educational. I wish I had science classes like that when I was in school.
Thank you! My bio teacher went through this really quickly and I didn't really understand it but now I fully understand! We had homework on it so this is a really great help!
I don't know if you'll see this but I just want to say thank you so much for this video! It is the most informative video I've seen in a while that connects links to many other biology concepts. I have a biology exam tomorrow and was struggling with this topic. This video helped immensely as it also gave a brief revision of adaptations, evolution etc :)
The agar cubes were EXTREMELY helpful in making us understand this concept. I couldn't understand SA:Vol even after reading hundreds of articles about it. THANK YOU FOR THIS VIDEO
Just wanted to revisit some concepts I was foggy on before hopping into advanced cell biology, the more years pass since Bio1 the more simple things seem to dissipate from my poor brain. What I found was actually a real delightful surprise- goodness gracious I wish more professors took the time to come up with neat examples like you have! Visuals can make or break a class for a lot of people, and this is a really well put together demonstration that would have been such a blessing to have when I was taking Bio1! Well, better to have discovered it late than never- I'll definitely have to binge-watch your videos at some point for some quality recaps on the basics, if not for just good 'ol fun.
bravo, bravo.. after watching so many videos of surface area to volume ration , when i got depressed and was about to give up , finally i understood after watching your video .......
ACHIEVE MORE BIOLOGY SUCCESS with learn-biology.com TEACHERS: Start with a free-trial account that gives your students access to interactive tutorials and allows you to monitor student work: learn-biology.com/ap-bio-teacher/ PARENTS: A guaranteed 4 or 5 for your son or daughter on the AP Bio Exam: learn-biology.com/parents/ STUDENTS: Crush your biology course with interactive lessons with flashcards, multiple choice questions, FRQs, and interactive diagrams: learn-biology.com/l-b_student-welcome/ PROFESSORS: Help your students master the most complex topics in biology. Sign for a free trial at: learn-biology.com/college-biology-success/
Honestly, you kept me very engaged with the pictures and the way you spoke really kept me inspired with the subject. Thank you for taking the time to make these videos!
Hi, i have one question: how could we apply this principle to construction? How does a big building differ from a smaller one? (if that were the case). Thanks a lot for the video, I was surprised and entretained all along.
Your channel has fun idea but he's else have needs in watching more people. i want help you be popularity! thank to clear heart, with love from russia!
Thanks! If you're interested, check out the tutorial I've made about this topic at learn-biology.com/ap-biology-v2-0-main-menu/ap-bio-unit-2-cell-structure-and-function-main-menu/topic-2-3-cell-size-surface-area-volume-and-life/ Let me know what you think.
can't thank you enough ! " The smaller the cube is the lager of its surface area volume, therefore it diffuse faster." would you give us the formula of the equation how to find the volume and surface area? Thank you on advance.
2:12 hey its just like that missile that knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position that it was, is now the position that it isn't. In the event that the position that it is in is not the position that it wasn't, the system has acquired a variation, the variation being the difference between where the missile is, and where it wasn't. If variation is considered to be a significant factor, it too may be corrected by the GEA. However, the missile must also know where it was. The missile guidance computer scenario works as follows. Because a variation has modified some of the information the missile has obtained, it is not sure just where it is. However, it is sure where it isn't, within reason, and it knows where it was. It now subtracts where it should be from where it wasn't, or vice-versa, and by differentiating this from the algebraic sum of where it shouldn't be, and where it was, it is able to obtain the deviation and its variation, which is called error.
Thanks, Hussein! If you're taking AP Bio, check out my AP Bio exam review plan: sciencemusicvideos.com/ap-biology/6-weeks-and-50-hours-to-a-4-or-5-on-this-years-ap-bio-exam/ Let me know what you think! Mr. W
Thank you very very much for making this video!! I was very confused bc in my Zoology class on presentation was writen: "Smaller animals have *bigger volume* so it is easier to loose body temperature and water" And i was sooo confused.. like: "How can a mouse have a *bigger volume* than a cat or a dog for example?" But *it is not volume* that is bigger but *ratio between surface and volume*.. And now I am so mad that they did not explain it properly.
There are cells that can grow larger in surface area to volume and vice versa. What are examples of that and how do they get around the surface volume ratio?
I was having a hard time understanding this and you made it so easy to understand with the visuals. I have one main question about the cell shapes. I was wondering if a torus ring would make a good cell shape??
you said that elephants can lose heat from their ears because they're flat etc but don't humans lose most of their heat through their head, how does this work? The video was really helpful though, thank you!
humans losing most heat through our heads is a myth. Usually the reason we lose a lot of heat from the head is the fact heads usually aren't covered with clothing. In all accuracy due to our head hair we are more likely to lose more heat through the hands or face then we would through our heads.
That's awesome, Erin. If you're taking AP Bio, check out my AP Bio exam review plan: sciencemusicvideos.com/ap-biology/6-weeks-and-50-hours-to-a-4-or-5-on-this-years-ap-bio-exam/ Let me know what you think! Mr. W
From Wikipedia, the free encyclopedia This article is about the generic concept of the time-dependent process. For other uses, see Diffusion (disambiguation). A diffusion is a process in physics. Some particles are dissolved in a glass of water. At first, the particles are all near one top corner of the glass. If the particles randomly move around ("diffuse") in the water, they eventually become distributed randomly and uniformly from an area of high concentration to an area of low concentration, and organized (diffusion continues, but with no net flux). File:Diffusion v2 20101120.ogv Time lapse video of diffusion of a dye dissolved in water into a gel. Diffusion from a microscopic and macroscopic point of view. Initially, there are solute molecules on the left side of a barrier (purple line) and none on the right. The barrier is removed, and the solute diffuses to fill the whole container. Top: A single molecule moves around randomly. Middle: With more molecules, there is a statistical trend that the solute fills the container more and more uniformly. Bottom: With an enormous number of solute molecules, all randomness is gone: The solute appears to move smoothly and deterministically from high-concentration areas to low-concentration areas. There is no microscopic force pushing molecules rightward, but there appears to be one in the bottom panel. This apparent force is called an entropic force. Three dimensional rendering of diffusion of purple dye in water. Diffusion is the net movement of molecules or atoms from a region of high concentration (or high chemical potential) to a region of low concentration (or low chemical potential) as a result of random motion of the molecules or atoms. Diffusion is driven by a gradient in chemical potential of the diffusing species. A gradient is the change in the value of a quantity e.g. concentration, pressure, or temperature with the change in another variable, usually distance. A change in concentration over a distance is called a concentration gradient, a change in pressure over a distance is called a pressure gradient, and a change in temperature over a distance is a called a temperature gradient. The word diffusion derives from the Latin word, diffundere, which means "to spread way out". A distinguishing feature of diffusion is that it depends on particle random walk, and results in mixing or mass transport without requiring directed bulk motion. Bulk motion, or bulk flow, is the characteristic of advection.[1] The term convection is used to describe the combination of both transport phenomena. Contents 1 Diffusion vs. bulk flow 2 Diffusion in the context of different disciplines 3 History of diffusion in physics 4 Basic models of diffusion 4.1 Diffusion flux 4.2 Fick's law and equations 4.3 Onsager's equations for multicomponent diffusion and thermodiffusion 4.4 Nondiagonal diffusion must be nonlinear 4.5 Einstein's mobility and Teorell formula 4.5.1 Teorell formula for multicomponent diffusion 4.6 Jumps on the surface and in solids 4.7 Diffusion in porous media 5 Diffusion in physics 5.1 Elementary theory of diffusion coefficient in gases 5.2 The theory of diffusion in gases based on Boltzmann's equation 5.3 Diffusion of electrons in solids 5.4 Diffusion in geophysics 6 Random walk (random motion) 6.1 Separation of diffusion from convection in gases 6.2 Other types of diffusion 7 See also 8 References Diffusion vs. bulk flow An example of a situation in which bulk motion and diffusion can be differentiated is the mechanism by which oxygen enters the body during external respiration known as breathing. The lungs are located in the thoracic cavity, which expands as the first step in external respiration. This expansion leads to an increase in volume of the alveoli in the lungs, which causes a decrease in pressure in the alveoli. This creates a pressure gradient between the air outside the body at relatively high pressure and the alveoli at relatively low pressure. The air moves down the pressure gradient through the airways of the lungs and into the alveoli until the pressure of the air and that in the alveoli are equal i.e. the movement of air by bulk flow stops once there is no longer a pressure gradient. The air arriving in the alveoli has a higher concentration of oxygen than the “stale” air in the alveoli. The increase in oxygen concentration creates a concentration gradient for oxygen between the air in the alveoli and the blood in the capillaries that surround the alveoli. Oxygen then moves by diffusion, down the concentration gradient, into the blood. The other consequence of the air arriving in alveoli is that the concentration of carbon dioxide in the alveoli decreases. This creates a concentration gradient for carbon dioxide to diffuse from the blood into the alveoli, as fresh air has a very low concentration of carbon dioxide compared to the blood in the body. The pumping action of the heart then transports the blood around the body. As the left ventricle of the heart contracts, the volume decreases, which increases the pressure in the ventricle. This creates a pressure gradient between the heart and the capillaries, and blood moves through blood vessels by bulk flow down the pressure gradient. As the thoracic cavity contracts during expiration, the volume of the alveoli decreases and creates a pressure gradient between the alveoli and the air outside the body, and air moves by bulk flow down the pressure gradient. Diffusion in the context of different disciplines Diffusion furnaces used for thermal oxidation The concept of diffusion is widely used in: physics (particle diffusion), chemistry, biology, sociology, economics, and finance (diffusion of people, ideas and of price values). However, in each case, the object (e.g., atom, idea, etc.) that is undergoing diffusion is “spreading out” from a point or location at which there is a higher concentration of that object. There are two ways to introduce the notion of diffusion: either a phenomenological approach starting with Fick's laws of diffusion and their mathematical consequences, or a physical and atomistic one, by considering the random walk of the diffusing particles.[2] In the phenomenological approach, diffusion is the movement of a substance from a region of high concentration to a region of low concentration without bulk motion. According to Fick's laws, the diffusion flux is proportional to the negative gradient of concentrations. It goes from regions of higher concentration to regions of lower concentration. Sometime later, various generalizations of Fick's laws were developed in the frame of thermodynamics and non-equilibrium thermodynamics.[3] From the atomistic point of view, diffusion is considered as a result of the random walk of the diffusing particles. In molecular diffusion, the moving molecules are self-propelled by thermal energy. Random walk of small particles in suspension in a fluid was discovered in 1827 by Robert Brown. The theory of the Brownian motion and the atomistic backgrounds of diffusion were developed by Albert Einstein.[4] The concept of diffusion is typically applied to any subject matter involving random walks in ensembles of individuals. Biologists often use the terms "net movement" or "net diffusion" to describe the movement of ions or molecules by diffusion. For example, oxygen can diffuse through cell membranes so long as there is a higher concentration of oxygen outside the cell. However, because the movement of molecules is random, occasionally oxygen molecules move out of the cell (against the concentration gradient). Because there are more oxygen molecules outside the cell, the probability that oxygen molecules will enter the cell is higher than the probability that oxygen molecules will leave the cell. Therefore, the "net" movement of oxygen molecules (the difference between the number of molecules either entering or leaving the cell) is into the cell. In other words, there is a net movement of oxygen molecules down the concentration gradient. History of diffusion in physics In the scope of time, diffusion in solids was used long before the theory of diffusion was created. For example, Pliny the Elder had previously described the cementation process, which produces steel from the element iron (Fe) through carbon diffusion. Another example is well known for many centuries, the diffusion of colours of stained glass or earthenware and Chinese ceramics. In modern science, the first systematic experimental study of diffusion was performed by Thomas Graham. He studied diffusion in gases, and the main phenomenon was described by him in 1831-1833:[5] "...gases of different nature, when brought into contact, do not arrange themselves according to their density, the heaviest undermost, and the lighter uppermost, but they spontaneously diffuse, mutually and equally, through each other, and so remain in the intimate state of mixture for any length of time.” The measurements of Graham contributed to James Clerk Maxwell deriving, in 1867, the coefficient of diffusion for CO2 in air. The error rate is less than 5%. In 1855, Adolf Fick, the 26-year-old anatomy demonstrator from Zürich, proposed his law of diffusion. He used Graham's research, stating his goal as "the development of a fundamental law, for the operation of diffusion in a single element of space". He asserted a deep analogy between diffusion and conduction of heat or electricity, creating a formalism that is similar to Fourier's law for heat conduction (1822) and Ohm's law for electric current (1827).
I didn't understand one thing; you said that shark can resist to super-cold temperature since it has big surface volume ration which make the heat trap inside, then you said when we cross our arms in the cold weather, we want to decrease diffusion and make the heat trap inside. But by crossing our arms, we decrease surface area while keeping the volume constant. Briefly, I think this two example deny each other. Please explain it, I am really confused
Hi Narmin, The whale is very big, with a lot of surface area, but a huge volume, so it has a very small surface area to volume ratio. Little heat can diffuse out. When you cross your arms, you decrease your surface area, and decrease your surface area to volume ratio, so it's harder for heat to diffuse out. Hope that helps! P.S. Try my tutorial at sciencemusicvideos.com Mr. W
Somehow I came to this looking for the definition of flocculation. The math in the table at the 2:50 mark was throwing me off. The surface area formula is 6(cm²).
GREAT QUESTION: They don't need to. Fish are exothermic: their body temperature matches the environment, so, in an evolutionary sense, they don't need to worry about heat loss! Please consider subscribing to my website: www.sciencemusicvideos.com. Check it out and let me know what you think! Mr. W
Sorry this is so late in coming. Here's one that I found: bio.libretexts.org/Bookshelves/Biotechnology/Bio-OER_(CUNY)/04%3A_Osmosis_and_Diffusion/4.06%3A_Agar_Cubes_(Preparation)
You're welcome, Dalton. Check out the tutorials I have about cells (and most other topics) at sciencemusicvideos.com/apbio2019/ Let me know what you think! Mr. W
Everyone say “thank you” to this man giving out knowledge for free
Thank you!
asian kid he gets paid to do this bud
@@imadiboyy my man, this guy doesn't get paid
@@imadiboyy the only thing he gets paid for is ad revenue which isn’t much 😂
@@aijsdijdni3401 Ik but he isn’t doing it for COMPLETELY free
Hi., those cubes look really delicious. I would like to consume them please
i was thinking that when we were doing it in school XD
Kalchimy123 im glad i wasnt the only one
They look tasty but I wouldn't eat it with the phenolphthalein. Agar is edible though, you can buy it in stores, it's used as a thickening agent. Phenolphthalein will make you sick if you eat it.
I think you are a bacteria
@@humaira7861 why don’t you make it 70. That way the process will be over.
Hi,
I just wanted to thank you for this video. Not only did you explain the topic very well, but you did it in a context that actually made me very happy to learn. This is something my teacher failed, and I just want to say how much I appreciate it because it means that I can actually enjoy studying this as I can see how it is with actual examples which interest me, instead of a boring flat and arbitrary experiment.
exactly the same situation i am in...
Thanks to this lad :)
You're exactly right. Without context, information that teachers throw at you is somewhat meaningless and not very interesting. I love how this guy so much enthusiasm and really enjoys what he is teaching, that quality in a teacher is worth paying for.
Yeah my teacher sucks
@@tomsaunders9944 ong
I don't know why, but this video actually wasn't boring and I was genuinely interested in some things. I wish you were my teacher.
Take my class! sciencemusicvideos.com/student-welcome/
Guaranteed 4 or 5 in AP Bio! Free trial at Learn-Biology.com/student-free-trial
One of the best videos explaining this topic of surface area and volume. The phenolphthaleine analogy was amazing, made it very easy to visualize the process of diffusion and the importance of surface area to volume ratio. And the applicability of this concept in real life made the video even more enjoyable and educational. I wish I had science classes like that when I was in school.
Thank you! My bio teacher went through this really quickly and I didn't really understand it but now I fully understand! We had homework on it so this is a really great help!
I don't know if you'll see this but I just want to say thank you so much for this video! It is the most informative video I've seen in a while that connects links to many other biology concepts. I have a biology exam tomorrow and was struggling with this topic. This video helped immensely as it also gave a brief revision of adaptations, evolution etc :)
The agar cubes were EXTREMELY helpful in making us understand this concept. I couldn't understand SA:Vol even after reading hundreds of articles about it. THANK YOU FOR THIS VIDEO
so glad to hear that. Check out the tutorial about this on my website, Learn-Biology.com
I remember being more mesmorized by these magical cubes than what they were supposed to be teaching lol
Just wanted to revisit some concepts I was foggy on before hopping into advanced cell biology, the more years pass since Bio1 the more simple things seem to dissipate from my poor brain. What I found was actually a real delightful surprise- goodness gracious I wish more professors took the time to come up with neat examples like you have! Visuals can make or break a class for a lot of people, and this is a really well put together demonstration that would have been such a blessing to have when I was taking Bio1! Well, better to have discovered it late than never- I'll definitely have to binge-watch your videos at some point for some quality recaps on the basics, if not for just good 'ol fun.
Your video saved my life. Thanks, Michael Keaton!
BEST VIDEO I HAVE EVER SEEN ON THIS TOPIC!
Brillante explicación, gracias por tomarte el tiempo de hacer estos videos llenos de fuerza y entusiasmo y mucho conocimiento. Un saludo.
Muchismas gracias! Suerte en sus estudios de biologia!
bravo, bravo.. after watching so many videos of surface area to volume ration , when i got depressed and was about to give up , finally i understood after watching your video .......
ACHIEVE MORE BIOLOGY SUCCESS with learn-biology.com
TEACHERS: Start with a free-trial account that gives your students access to interactive tutorials and allows you to monitor student work: learn-biology.com/ap-bio-teacher/
PARENTS: A guaranteed 4 or 5 for your son or daughter on the AP Bio Exam: learn-biology.com/parents/
STUDENTS: Crush your biology course with interactive lessons with flashcards, multiple choice questions, FRQs, and interactive diagrams: learn-biology.com/l-b_student-welcome/
PROFESSORS: Help your students master the most complex topics in biology. Sign for a free trial at: learn-biology.com/college-biology-success/
I wasn't planning to watch the whole video but I watched the whole thing he explained in such a interesting manner
Honestly, you kept me very engaged with the pictures and the way you spoke really kept me inspired with the subject. Thank you for taking the time to make these videos!
i love the practical examples he uses to teach. talk about one good teacher :)
Thank you very much for making this video! You helped another person learn something new today.
Hi, i have one question: how could we apply this principle to construction? How does a big building differ from a smaller one? (if that were the case). Thanks a lot for the video, I was surprised and entretained all along.
Great video, I am using this in a lecture on soil science and tree biology
This is the BEST video for this concept. Thank You !
Thanks, Sally. What other topics are you interested in?
good job you are good teacher like organic chemistry tutor
Watching this in school, thank you so much😁👍
Great video sir! Thank you so much for spending the time to share such a powerful concept :D
The best explanation with real life experiences.
Your channel has fun idea but he's else have needs in watching more people. i want help you be popularity! thank to clear heart, with love from russia!
thank you so so much! you explained everything so well, super helpful! :)
The best teaching I’ve seen in a video. Very helpful
Wow, thank you!
I still don’t get it ;(
its been 2 years, do u get it yet
@@GrimReaper-er8uu LMAO!!🤣🤣
It's been 5 years, have you gotten it yet?
Great Vid! Made me understand this topic well!
Where are you live ? amazing, now I am going to you learn about biology.god bless you!!!
I'm going to figure out going live in 2024. It'll be right here on this channel.
Thank you! This video is really helpful.
I'm so glad!
THANK YOU!!! THANK YOU!!! :)
This is a brilliant video. Thank you.
Thanks! If you're interested, check out the tutorial I've made about this topic at learn-biology.com/ap-biology-v2-0-main-menu/ap-bio-unit-2-cell-structure-and-function-main-menu/topic-2-3-cell-size-surface-area-volume-and-life/
Let me know what you think.
@@sciencemusicvideos , yes, I shall do that. Thank you very much for directing me to extra invaluable sources.
@@sciencemusicvideos, Is the Biomania App available for PCs?
Thank you so much! I hope you realise how much you help people, your work is very much appreciated 💓
Wow, you explain very well thank you!
can't thank you enough ! " The smaller the cube is the lager of its surface area volume, therefore it diffuse faster."
would you give us the formula of the equation how to find the volume and surface area?
Thank you on advance.
Hi Seni,
Check out my tutorial at www.sciencemusicvideos.com/surface-area-volume-and-life/
Enjoy!
Mr. W
really good explanation with the cubes, nice vid
Our teacher recommend this video n not bad at all
2:12 hey its just like that missile that knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is (whichever is greater), it obtains a difference, or deviation. The guidance subsystem uses deviations to generate corrective commands to drive the missile from a position where it is to a position where it isn't, and arriving at a position where it wasn't, it now is. Consequently, the position where it is, is now the position that it wasn't, and it follows that the position that it was, is now the position that it isn't.
In the event that the position that it is in is not the position that it wasn't, the system has acquired a variation, the variation being the difference between where the missile is, and where it wasn't. If variation is considered to be a significant factor, it too may be corrected by the GEA. However, the missile must also know where it was.
The missile guidance computer scenario works as follows. Because a variation has modified some of the information the missile has obtained, it is not sure just where it is. However, it is sure where it isn't, within reason, and it knows where it was. It now subtracts where it should be from where it wasn't, or vice-versa, and by differentiating this from the algebraic sum of where it shouldn't be, and where it was, it is able to obtain the deviation and its variation, which is called error.
Helpful video Thanks
i was having trouble understanding SA to volume ratio but I get it now! thank you!
Thank you very much .I think it is the best video that has been made on this concept.cheers👍
Thanks, Hussein! If you're taking AP Bio, check out my AP Bio exam review plan: sciencemusicvideos.com/ap-biology/6-weeks-and-50-hours-to-a-4-or-5-on-this-years-ap-bio-exam/
Let me know what you think!
Mr. W
Ohhh its amazing 😊☺🤗tysm
THANK-YOU! I understand this concept a lot more.
it is superb
first time in 3 years i can understand this concept very well
Thank you very very much for making this video!! I was very confused bc in my Zoology class on presentation was writen: "Smaller animals have *bigger volume* so it is easier to loose body temperature and water" And i was sooo confused.. like: "How can a mouse have a *bigger volume* than a cat or a dog for example?" But *it is not volume* that is bigger but *ratio between surface and volume*.. And now I am so mad that they did not explain it properly.
Thank you!
this guy easily got my sub, thx for explaining the concept!
There are cells that can grow larger in surface area to volume and vice versa. What are examples of that and how do they get around the surface volume ratio?
Thank you so much for this video
Thank you so much for this!
Thank you so very much!! You made my day by making me understanding this SA vs Vo ration thingy!! :))
Awesome ! I'm so glad it was helpful!
Thank you, this is very apriciated especially when I'm struggling 🙂
Thank you
thank you
Thank you very much for your well explained and demonstrated concept 🙌🏾
I was having a hard time understanding this and you made it so easy to understand with the visuals. I have one main question about the cell shapes. I was wondering if a torus ring would make a good cell shape??
Thanks for the video. We are doing this in school and it really helped me out. 🙃
excellent video, very good explanation
It really helped a lot
you said that elephants can lose heat from their ears because they're flat etc but don't humans lose most of their heat through their head, how does this work?
The video was really helpful though, thank you!
humans losing most heat through our heads is a myth. Usually the reason we lose a lot of heat from the head is the fact heads usually aren't covered with clothing. In all accuracy due to our head hair we are more likely to lose more heat through the hands or face then we would through our heads.
thanks
Great descriptions and explanations!
Thank you so much! I fully understand this concept now, and you made it so fun, interesting and enjoyable!
That's awesome, Erin.
If you're taking AP Bio, check out my AP Bio exam review plan: sciencemusicvideos.com/ap-biology/6-weeks-and-50-hours-to-a-4-or-5-on-this-years-ap-bio-exam/
Let me know what you think!
Mr. W
From Wikipedia, the free encyclopedia
This article is about the generic concept of the time-dependent process. For other uses, see Diffusion (disambiguation).
A diffusion is a process in physics. Some particles are dissolved in a glass of water. At first, the particles are all near one top corner of the glass. If the particles randomly move around ("diffuse") in the water, they eventually become distributed randomly and uniformly from an area of high concentration to an area of low concentration, and organized (diffusion continues, but with no net flux).
File:Diffusion v2 20101120.ogv
Time lapse video of diffusion of a dye dissolved in water into a gel.
Diffusion from a microscopic and macroscopic point of view. Initially, there are solute molecules on the left side of a barrier (purple line) and none on the right. The barrier is removed, and the solute diffuses to fill the whole container. Top: A single molecule moves around randomly. Middle: With more molecules, there is a statistical trend that the solute fills the container more and more uniformly. Bottom: With an enormous number of solute molecules, all randomness is gone: The solute appears to move smoothly and deterministically from high-concentration areas to low-concentration areas. There is no microscopic force pushing molecules rightward, but there appears to be one in the bottom panel. This apparent force is called an entropic force.
Three dimensional rendering of diffusion of purple dye in water.
Diffusion is the net movement of molecules or atoms from a region of high concentration (or high chemical potential) to a region of low concentration (or low chemical potential) as a result of random motion of the molecules or atoms. Diffusion is driven by a gradient in chemical potential of the diffusing species.
A gradient is the change in the value of a quantity e.g. concentration, pressure, or temperature with the change in another variable, usually distance. A change in concentration over a distance is called a concentration gradient, a change in pressure over a distance is called a pressure gradient, and a change in temperature over a distance is a called a temperature gradient.
The word diffusion derives from the Latin word, diffundere, which means "to spread way out".
A distinguishing feature of diffusion is that it depends on particle random walk, and results in mixing or mass transport without requiring directed bulk motion. Bulk motion, or bulk flow, is the characteristic of advection.[1] The term convection is used to describe the combination of both transport phenomena.
Contents
1 Diffusion vs. bulk flow
2 Diffusion in the context of different disciplines
3 History of diffusion in physics
4 Basic models of diffusion
4.1 Diffusion flux
4.2 Fick's law and equations
4.3 Onsager's equations for multicomponent diffusion and thermodiffusion
4.4 Nondiagonal diffusion must be nonlinear
4.5 Einstein's mobility and Teorell formula
4.5.1 Teorell formula for multicomponent diffusion
4.6 Jumps on the surface and in solids
4.7 Diffusion in porous media
5 Diffusion in physics
5.1 Elementary theory of diffusion coefficient in gases
5.2 The theory of diffusion in gases based on Boltzmann's equation
5.3 Diffusion of electrons in solids
5.4 Diffusion in geophysics
6 Random walk (random motion)
6.1 Separation of diffusion from convection in gases
6.2 Other types of diffusion
7 See also
8 References
Diffusion vs. bulk flow
An example of a situation in which bulk motion and diffusion can be differentiated is the mechanism by which oxygen enters the body during external respiration known as breathing. The lungs are located in the thoracic cavity, which expands as the first step in external respiration. This expansion leads to an increase in volume of the alveoli in the lungs, which causes a decrease in pressure in the alveoli. This creates a pressure gradient between the air outside the body at relatively high pressure and the alveoli at relatively low pressure. The air moves down the pressure gradient through the airways of the lungs and into the alveoli until the pressure of the air and that in the alveoli are equal i.e. the movement of air by bulk flow stops once there is no longer a pressure gradient.
The air arriving in the alveoli has a higher concentration of oxygen than the “stale” air in the alveoli. The increase in oxygen concentration creates a concentration gradient for oxygen between the air in the alveoli and the blood in the capillaries that surround the alveoli. Oxygen then moves by diffusion, down the concentration gradient, into the blood. The other consequence of the air arriving in alveoli is that the concentration of carbon dioxide in the alveoli decreases. This creates a concentration gradient for carbon dioxide to diffuse from the blood into the alveoli, as fresh air has a very low concentration of carbon dioxide compared to the blood in the body.
The pumping action of the heart then transports the blood around the body. As the left ventricle of the heart contracts, the volume decreases, which increases the pressure in the ventricle. This creates a pressure gradient between the heart and the capillaries, and blood moves through blood vessels by bulk flow down the pressure gradient. As the thoracic cavity contracts during expiration, the volume of the alveoli decreases and creates a pressure gradient between the alveoli and the air outside the body, and air moves by bulk flow down the pressure gradient.
Diffusion in the context of different disciplines
Diffusion furnaces used for thermal oxidation
The concept of diffusion is widely used in: physics (particle diffusion), chemistry, biology, sociology, economics, and finance (diffusion of people, ideas and of price values). However, in each case, the object (e.g., atom, idea, etc.) that is undergoing diffusion is “spreading out” from a point or location at which there is a higher concentration of that object.
There are two ways to introduce the notion of diffusion: either a phenomenological approach starting with Fick's laws of diffusion and their mathematical consequences, or a physical and atomistic one, by considering the random walk of the diffusing particles.[2]
In the phenomenological approach, diffusion is the movement of a substance from a region of high concentration to a region of low concentration without bulk motion. According to Fick's laws, the diffusion flux is proportional to the negative gradient of concentrations. It goes from regions of higher concentration to regions of lower concentration. Sometime later, various generalizations of Fick's laws were developed in the frame of thermodynamics and non-equilibrium thermodynamics.[3]
From the atomistic point of view, diffusion is considered as a result of the random walk of the diffusing particles. In molecular diffusion, the moving molecules are self-propelled by thermal energy. Random walk of small particles in suspension in a fluid was discovered in 1827 by Robert Brown. The theory of the Brownian motion and the atomistic backgrounds of diffusion were developed by Albert Einstein.[4] The concept of diffusion is typically applied to any subject matter involving random walks in ensembles of individuals.
Biologists often use the terms "net movement" or "net diffusion" to describe the movement of ions or molecules by diffusion. For example, oxygen can diffuse through cell membranes so long as there is a higher concentration of oxygen outside the cell. However, because the movement of molecules is random, occasionally oxygen molecules move out of the cell (against the concentration gradient). Because there are more oxygen molecules outside the cell, the probability that oxygen molecules will enter the cell is higher than the probability that oxygen molecules will leave the cell. Therefore, the "net" movement of oxygen molecules (the difference between the number of molecules either entering or leaving the cell) is into the cell. In other words, there is a net movement of oxygen molecules down the concentration gradient.
History of diffusion in physics
In the scope of time, diffusion in solids was used long before the theory of diffusion was created. For example, Pliny the Elder had previously described the cementation process, which produces steel from the element iron (Fe) through carbon diffusion. Another example is well known for many centuries, the diffusion of colours of stained glass or earthenware and Chinese ceramics.
In modern science, the first systematic experimental study of diffusion was performed by Thomas Graham. He studied diffusion in gases, and the main phenomenon was described by him in 1831-1833:[5]
"...gases of different nature, when brought into contact, do not arrange themselves according to their density, the heaviest undermost, and the lighter uppermost, but they spontaneously diffuse, mutually and equally, through each other, and so remain in the intimate state of mixture for any length of time.”
The measurements of Graham contributed to James Clerk Maxwell deriving, in 1867, the coefficient of diffusion for CO2 in air. The error rate is less than 5%.
In 1855, Adolf Fick, the 26-year-old anatomy demonstrator from Zürich, proposed his law of diffusion. He used Graham's research, stating his goal as "the development of a fundamental law, for the operation of diffusion in a single element of space". He asserted a deep analogy between diffusion and conduction of heat or electricity, creating a formalism that is similar to Fourier's law for heat conduction (1822) and Ohm's law for electric current (1827).
So helpful!! You're awesome!
awesome!
Thank you kind sir
Whales have low surface area to volume ratios as spherical shapes have greater volumes and a lot less surface area
Thank you for this video it was really helpful... cant u be my biology teacher ♥
beautifully explained!!
mr Peter you madlad
awesome explanation! Thanks.
Great video. I wish you would have done the formula it as well.
I didn't understand one thing; you said that shark can resist to super-cold temperature since it has big surface volume ration which make the heat trap inside, then you said when we cross our arms in the cold weather, we want to decrease diffusion and make the heat trap inside. But by crossing our arms, we decrease surface area while keeping the volume constant. Briefly, I think this two example deny each other. Please explain it, I am really confused
Hi Narmin,
The whale is very big, with a lot of surface area, but a huge volume, so it has a very small surface area to volume ratio. Little heat can diffuse out. When you cross your arms, you decrease your surface area, and decrease your surface area to volume ratio, so it's harder for heat to diffuse out. Hope that helps!
P.S. Try my tutorial at sciencemusicvideos.com
Mr. W
Better than crash course diffusion video
That's high praise, because I love those guys!
Thanks! Tell your friends and teachers about www.sciencemusicvideos.com.
Mr. W
nice job but you can make the examples easer but over all its very nice
One concept to explain them all, One concept to find them...
Finally, someone who gets the reference! Thanks, Brickmaster!
GREAT VIDEO!!!!!
this is an excellent and thorough explanation!
Thanks, Adriana. I also have a tutorial at www.sciencemusicvideos.com/surface-area-volume-and-life/
Check it out and let me know what you think!
Mr. W
thank you so much
thanks man
Nice Vid helped me a lot, keep up the good work!
thanks so much!
Sir can you explain surface area to volume ratio in nano material and the advantages.
Somehow I came to this looking for the definition of flocculation. The math in the table at the 2:50 mark was throwing me off. The surface area formula is 6(cm²).
good job
thank you !!
This was perfect. Did better than my loudmouth teacher
May be a stupid question - but whales can maintain a high body temp due to their low SA:Vol, how do small fish with a high sa:vol do this? Thanks
GREAT QUESTION: They don't need to. Fish are exothermic: their body temperature matches the environment, so, in an evolutionary sense, they don't need to worry about heat loss!
Please consider subscribing to my website: www.sciencemusicvideos.com. Check it out and let me know what you think!
Mr. W
Does surface area depends on the organs of an organism
Can you please define how to make the agar cubes.
Sorry this is so late in coming. Here's one that I found: bio.libretexts.org/Bookshelves/Biotechnology/Bio-OER_(CUNY)/04%3A_Osmosis_and_Diffusion/4.06%3A_Agar_Cubes_(Preparation)
you are a legend
Well, as my mother used to say, that and a dollar gets me onto the bus! But thanks!!
Thanks!!
You're welcome, Dalton. Check out the tutorials I have about cells (and most other topics) at sciencemusicvideos.com/apbio2019/
Let me know what you think!
Mr. W
I loved this ,now i get the concept..thank you so much
Hi Melisa. Please check out my tutorial on this at www.sciencemusicvideos.com/surface-area-volume-and-life/
Enjoy!
Mr. W
My school syllabus has the link of this video
That’s awesome! Are you also using learn-biology.com as your course textbook?
Thank you for doing this video! Very helpful and much appreciated! God bless you in Jesus' name I pray Amen!