Hi Mel. Today I passed my European Air Transportation Pilot Licence theory exam. It includes Meteorology. That was the field I was fearing the most. You helped me a lot understanding some concepts. Thanks a lot. I hope the cat is doing well.
I love clouds sm, I really liked the way you talk through your lectures. I have adhd and autism, I find it difficult to sit through lecture style courses but this one was hands on and thoroughly explained. I didn’t find it difficult to absorb the information and I could simply pause to take notes.
I'm a federal wildland fire lookout. These are really helpful to me in my work, though I'm probably starting to sound like a know it all in my daily weather updates. Thanks Mel and love the cat.
Fantastic videos, everything explained, demonstrated so clearly yet thoroughly, with humour. I m not a student, just interested in the weather, and i think Mels teaching techniques are superb.
I am taking US Power Squadron courses for boaters and on the Weather Course. Your lectures completely reinforced, clarified, put the course content in context. You explained the 'why' and 'how'....besides that your instruction delivery is addictive to want to learn more...kudos
As a glider pilot I have experienced thermals many times. That's why we fly in tight circles to remain in the thermal as long as possible unlike the 'bird brains'. Sometimes the aircraft shudders noticeable in the thermal as is rises. Great video.
We are taught in aviation the temperature lapse rate is 2°C/3°F for every 1000’. I always thought it was the dry rate not the wet rate. That cat likes to sleep! Thank you for the polishing of my weather knowledge.
The dry rate is always given as a constant or 5.4F/1000'. However, the moist/saturated/wet rate is not exactly a constant. It will vary a little depending on dew point and other conditions. So it is given as a range, such as the 2F/3F in your example. In all of my lectures I use a 'constant' rate of 2.7F/1000' to keep things simpler. Other instructors might use a different number for this. Mother Nature does not use a constant value though.
Echoing the other comments here; awesome content! Been spending months reading, watching, searching for weather material and these lectures are the BEST. Thank you
I’m a Paraglider pilot in the UK, and these lectures (and this one in particular) is basically the syllabus for the pilots exam. Superb. Thanks @melstrong!
@@MelStrong another student pilot here, working on my PPL nav and struggling to visualise what a "convective" cell and an inversion layer mean to the process. This content was exactly what I needed. Loved every minute. Thank you
I’ve always looked up to the sky and wondered these questions you stated in the video, why clouds are here but not there, why they start here and stop there. It’s all crystal clear to me now thank you
My brother does paragliding, and from what he told me birds are much better at staying in thermals than human paragliders. He often says he wishes he knew how the birds are doing it. It's just that depending on the conditions it might actually be really difficult to stay inside the thermal, even for them. Or they might willingly leave the thermal because they want to remain at a specific height above the ground, for example to spot prey. Or they might just be fooling around and flying for fun.
I'm pretty sure the birds have developed some specific intuition about it in the process of evolution, just like they have developed large wings for prolonged gliding. They certainly don't do any analysis of the landscape or cloud pattern, but they might subconsciously prefer soaring over the fields rather than water or forest, and staying on the windward side of the mountains. Besides, the birds are probably very sensitive to slightest changes in relative wind, and they adjust immediately as they sense a decrease in an updraft...
I'm so happy!! I watches all your previous classes excited to finally be able to understand the creation of clouds, I can't wait to finally discover this mystery hahha :))
I'm coursing my masters in Geography, and these lectures have helped so much to understand the different processes. Thank you so much. Your instruction is inspirational!
On a cold mornings where outside temperature is cooler compared to what we exhale (warm and moist air ).. then as per Dry Adiabatic Lapse Rate - 6.5C per km, when we exhale out .. the exhaled air is warmer than the surrounding, so it should ascend and while ascending, it cools and when the air can no longer hold vapor it condenses .. so we should see clouds forming little higher than us because of the ascending and cooling
Thanks for posting these lectures. I've been a cloud enthusiast for a few years and this particular lesson marked the first time I grappled successfully with dew point, relative humidity, altitude, air parcels, and formation of the cloud base. The mountain examples along with the supplement to this lesson really made certain in my mind the meaning of lapse rates. And the bonus was actually calculating cloud bases and heights. I have a camera pointed skyward (currently to the west at an elevation of 30 degrees) and Python code that captures an image every ~20 seconds. I have had marginal success building a neural network model to predict probabilities of what is in the camera view. It is still flawed. However these lessons are spinning some gears upstairs on how I can take this new knowledge and do something even more interesting. Thanks again.
Thanks! I'm not a programmer but am currently struggling to learn Python. Well...a flavor of Python called CircuitPython....but that is a cool project to take pictures at certain intervals.
@@MelStrong I wasn't familiar with CircuitPython. I have used Python on my collection of Raspberry Pi to collect weather data from a sensor board as well as a screen capture of the sky. Are you intending to interface with some boards using Python?
@@cppprogramming Mostly trying to build some interactive devices/exhibits, though if I got good enough I'd like to be able to gather data from various sensors.
@@MelStrong I used the Sense HAT for the Raspberry Pi. It sits on the PI3 and measures temperature, pressure, humidity, along with all the intertial measurements (angular rates and accelerations). The inertial data can correlate indirectly I think (vibrations) to wind speed. Although I did not persure that. Here's my rig including the vertical facing IP camera. instagram.com/p/B64dBr8gLIc/
These lectures are absolutely fantastic, you are a great teacher. I’m a chemical engineer and it’s great to put all the thermodynamics, heat transfer, unit operations etc. knowledge into understanding the nature around me. The only con is the use of imperial units which are retarded by definition, but well, it’s MURICA 😂 thank you heaps Mel!
Thanks so much Mel, we highly appreciate this I'm, for the first time I'm fully understanding cloud formation. I'm writing my drone instructor exam soon and one of the presentations I need to do is on Meteorology.
Thanks - this is just what I've been looking for. However, there is a little mathematical problem with the Butane combustion formula at the 8:00 mark - there should be 2 x Butane molecules for the equation to balance.
Yes I usually don't balance any of my chemical equations in any of my lectures because they were originally intended for a non-science audience and I didn't want to add any additional complications for them.
Omg. Suddenly I understand the difference between wet and dry adiabatic laps rates! What a build up! What a revelation! I feell like a third eye has been opened in my forehead!
Mel, thank you so much for making these available - you're doing the world a real service! Since I had more time on my hands due to lockdown, I decided I might as well learn something new. Your lectures are brilliantly informative and have inspired me to create a simple program to predict whether conditions support convection-based cloud formation. However, I'm not sure what the right method to use is. Is it more accurate to assume a parcel of air at current air temperature with a certain dew point and compare that with a 'standard' atmosphere for the time of year, or to assume a parcel with temperature equal to current surface temperature and compare that with air temperature?
Well I would start with the current temperature and dew point at the surface. You can create a formula that will calculate the new temperature of the rising air parcel at different altitudes based on the dry adiabatic lapse rate, and then onwards with the saturated adiabatic rate once saturation is reached. You would want to compare the temperatures of your parcel to the actual temperatures aloft. To do that, you could obtain recent weather balloon data. Every 12 hours weather balloons across the world go up, and you can find that data online. One place to start is the University of Wyoming archive of atmospheric soundings, which updates every day with new data (link is below). You'd want to find the sounding closest to where you live. That would give you the temperatures aloft. You could then compare your hypothetical rising plume of air and see if it would indeed continue to rise or not based on the surrounding temperatures. Then to make it more realistic, you could use the approximation that your parcel of air loses 1 degree C of dew point for every 1km it rises. This is due to the expansion of air and some mixing of drier air into the parcel. I don't do this when I am calculating clouds on paper, but it would be easy to code that in and would be more realistic. You might even be able to figure out a way to have the program automatically download the most recent weather balloon data and current temperature/dew point from your nearest weather station, and then have it calculate what it thinks will happen...then check out the sky each day to see if it is correct! One reason that this might not work is that in some locations the weather balloon rises very early in the morning, when there is a temperature inversion at the surface. That temperature inversion goes away after the sun is up for a couple of hours, but it will mess up your math because the inversion will prevent air from rising. weather.uwyo.edu/upperair/sounding.html
That's really helpful, thanks. If I'm allowed to take up your time (briefly) again: if my model finds that the plume of air rises, hits the dew point and continues to cool until it reaches -40C, is this a somewhat decent indicator of rain?
Thank you for these lectures! I hope someone can help me out with this question: When warm air rises up and stops at some height (when its temperature is equal to the surrounding air), why does it sink back down it it is already in equilibrium with the surrounding air? Also, why does convection form a cycle? I can't reason out why the air moves sideways and then downwards after rising up. What determines the distance the air moves horizontally before it sinks down (what decided the horizontal size of the convection cell)?
One question, I see cumulus clouds always moving with the wind. Do the thermals move with them? Or does the cloud leave the thermal and starts dissipating? Amazing content thanks ☺️
Thanks for these! I'm using your lectures to help gain the knowledge necessary for my helo pilots license. I appreciate your efforts! Quick question.. Are the Adiabatic Lapse Rates based on temperature loss due to our normal temperature lapse rate (air is cooler as we go higher unless inversion) OR is it based on air expansion and temperature change due to pressure loss? Looking forward to continuing through this playlist.
The balloon representing a "parcel of air" placed inside the vacuum chamber really drove the point home about air parcels expanding with altitude. Of course, I did grimace when the balloon filled the entire chamber, expecting some sort of explosion or pop. =)
The balloon has popped on occasion when I have demoed this in class. However, since all of the air is sucked out of the chamber, the 'pop' makes very little noise. But everyone in class is holding their ears when the balloon gets big :). Strangely, it more often pops when I let the air back in - it flies around in there and then suddenly pops but I don't know what it is hitting.
@@MelStrong I wonder if the sudden temperature change with the balloon compression may be popping it? Or I suspect that the air is returned via a single port and I the air velocity may be high enough to puncture the surface much like a finger poking a bubble. I didn't hold my ears but I certainly winced. =)
@@MelStrong I assume it is due to elastic instability of balloon rubber and sudden pressure change created as air rushes back in the chamber. Shout out to you Sir from a budding geographer from India ! Generally it is more difficult to get basic concepts across to students ; they either misunderstand or lose the flow of a topic. However , you've explained everything very clearly in your video . Keep up the good work !
Hey Mel, Great content, well done for your work! I have one question. If rising air expands then,why do clouds have bigger flat bottoms and so much smaller tops? It's like air is siniking. Thanks
In reality as soon as air starts to rise from the surface, there is air sinking down (from above) to replace it. It happens concurrently. When the rising plume of air reaches the top of the thermal or cloud, it will eventually make its way back down to the surface. There does not need to be any removal of water at all for this to happen.
Amazing content! I had a question, you only mentioned the dew point on surface, but wouldn’t the dew point change with altitude? Does the dew point on surface dictate when cloud developments will happen above it?
If you were to sample air around the world you would find that yes the dew point decreases with altitude. For convective cloud formation, I am using the assumption that the parcel of air rising from the surface is completely isolated (adiabatic) and doesn't mix with any of the surrounding air. In reality, there is some mixing that occurs, which does lower the dew point a little bit as the parcel ascends. Also, as the parcel expands, that lowers the dew point as well even though we aren't subtracting any water from the air (think of it as the water molecules are becoming farther apart as the air expands. I make the assumption that the dew point doesn't change as the parcel rises to make the math easier when we are plotting out where clouds might form in the atmosphere. In general though, it is true that the higher the dew point at the surface, the lower the cloud base if temperatures are equal on comparable days.
@@MelStrong I think I've finally made sense of the way the dew point changes with altitude. Simply speaking, as we go up, the mixing ratio reduces. There are less water molecules per volume of air up there.
@@MelStrong but then, here is a question: if we were to calculate the height of the cloud base precisely, shouldn't we have taken the lowering of the dew point into consideration? It must be a few degrees lower as we go up several thousand feet...
@@gregory.chalenko Well the main reason that the dew point is lowering as you go up is because the air that is up there has already undergone this process that I'm talking about. In order for air to get up to say 5km up in the atmosphere, it already had to rise up, expand, cool, and condensate out water, leaving it with a lower dew point than it had at the surface. An air parcel at a given height has a history - it originally came from somewhere else, and however it got there, condensation removed water from it on the way up. When I am doing the math on calculating cloud base, I am assuming that there is no mixing and that the rising air parcel is perfectly isolated. So as that parcel rises, it is not losing or gaining water or heat from the surrounding air. That assumption is pretty close to reality - rising parcels are fairly isolated from their surroundings. However, it is true that a rising parcel of air can 'suck in' dry surrounding air, which further lowers the dew point. If we wanted to be extra precise in our calculations, we could also account for the fact that there is a decrease of dew point in a rising air parcel simply due to the expansion of the rising air (same amount of water molecules but in a larger and larger volume). An approximation often used is that a rising parcel of air is lowering its dew point by about 1C/km simply from the expansion of air. I avoid this to make the math easier, but you could include that to make more precise cloudbase calculations.
UA-cam on the climate change bit has a caption saying that ‘climate change is mainly caused by humans’ …mainly is the word they chose…my goodness. I believe even you know that’s a little over the top. Lol
"Cuz MERICA that's why!"
Subscribed!
Same 😂💪🏽
Hi Mel. Today I passed my European Air Transportation Pilot Licence theory exam. It includes Meteorology. That was the field I was fearing the most. You helped me a lot understanding some concepts. Thanks a lot. I hope the cat is doing well.
Airline Pilot here…from Brazil. Mann, internet is amazing! Thanks for the matter.
I love clouds sm, I really liked the way you talk through your lectures. I have adhd and autism, I find it difficult to sit through lecture style courses but this one was hands on and thoroughly explained. I didn’t find it difficult to absorb the information and I could simply pause to take notes.
I love these videos! Tonight I will raise a toast to condensation nuclei. For without them we had have no clouds or rain!
Fantastic content, great teaching style and a much appreciated sense of humor... very well done
Thanks! Appreciate the feedback.
I'm a federal wildland fire lookout. These are really helpful to me in my work, though I'm probably starting to sound like a know it all in my daily weather updates. Thanks Mel and love the cat.
I am bummed it took me so long to find this guy. Great content! I will be binging on learning more about how weather works.
Fantastic videos, everything explained, demonstrated so clearly yet thoroughly, with humour. I m not a student, just interested in the weather, and i think Mels teaching techniques are superb.
Couldn't agree with you more.
I am taking US Power Squadron courses for boaters and on the Weather Course. Your lectures completely reinforced, clarified, put the course content in context. You explained the 'why' and 'how'....besides that your instruction delivery is addictive to want to learn more...kudos
As a glider pilot I have experienced thermals many times. That's why we fly in tight circles to remain in the thermal as long as possible unlike the 'bird brains'. Sometimes the aircraft shudders noticeable in the thermal as is rises. Great video.
I haven't personally done any gliding but from what I have heard, a strong thermal can give you quite a ride!
Loved this lecture, particularly the bit about condensation trails. So much to learn about the atmosphere and properties of air!
Fantastic! Crystal clear and entertaining. Stronger than ever.
Thanks...appreciate the feedback.
We are taught in aviation the temperature lapse rate is 2°C/3°F for every 1000’. I always thought it was the dry rate not the wet rate.
That cat likes to sleep! Thank you for the polishing of my weather knowledge.
The dry rate is always given as a constant or 5.4F/1000'. However, the moist/saturated/wet rate is not exactly a constant. It will vary a little depending on dew point and other conditions. So it is given as a range, such as the 2F/3F in your example. In all of my lectures I use a 'constant' rate of 2.7F/1000' to keep things simpler. Other instructors might use a different number for this. Mother Nature does not use a constant value though.
Echoing the other comments here; awesome content! Been spending months reading, watching, searching for weather material and these lectures are the BEST. Thank you
I'm studying marine weather, and this video was very helpful. Other sailors should know about this series. Thank you so much!
I’m a Paraglider pilot in the UK, and these lectures (and this one in particular) is basically the syllabus for the pilots exam. Superb. Thanks @melstrong!
Hey good to know! Thanks!
Another PG pilot here from Australia and these videos have been great to further my understanding!
@@MelStrong another student pilot here, working on my PPL nav and struggling to visualise what a "convective" cell and an inversion layer mean to the process. This content was exactly what I needed. Loved every minute. Thank you
I’ve always looked up to the sky and wondered these questions you stated in the video, why clouds are here but not there, why they start here and stop there. It’s all crystal clear to me now thank you
Thanks - hope it was helpful
You do a great job. A briliant mind. I really admire you Mel😊
My brother does paragliding, and from what he told me birds are much better at staying in thermals than human paragliders. He often says he wishes he knew how the birds are doing it. It's just that depending on the conditions it might actually be really difficult to stay inside the thermal, even for them. Or they might willingly leave the thermal because they want to remain at a specific height above the ground, for example to spot prey. Or they might just be fooling around and flying for fun.
I'm pretty sure the birds have developed some specific intuition about it in the process of evolution, just like they have developed large wings for prolonged gliding. They certainly don't do any analysis of the landscape or cloud pattern, but they might subconsciously prefer soaring over the fields rather than water or forest, and staying on the windward side of the mountains. Besides, the birds are probably very sensitive to slightest changes in relative wind, and they adjust immediately as they sense a decrease in an updraft...
Woow, what a fantastic video series. What a great teacher! Thank you very much! Greeting from the Netherlands from a student pilot (PPL)!!
I've enjoyed this lecture a lot, learned so many things I didn't know in detail!
Mel, i can´t than you enogh. As i´m in the process of studying for ATPL meteorology, these lectures come very helpful.
I'm so happy!! I watches all your previous classes excited to finally be able to understand the creation of clouds, I can't wait to finally discover this mystery hahha :))
I'm coursing my masters in Geography, and these lectures have helped so much to understand the different processes. Thank you so much. Your instruction is inspirational!
You've made cloud formation crystal clear--this made so much sense to me. Thank you so much.
On a cold mornings where outside temperature is cooler compared to what we exhale (warm and moist air ).. then as per Dry Adiabatic Lapse Rate - 6.5C per km, when we exhale out .. the exhaled air is warmer than the surrounding, so it should ascend and while ascending, it cools and when the air can no longer hold vapor it condenses .. so we should see clouds forming little higher than us because of the ascending and cooling
Thanks for posting these lectures. I've been a cloud enthusiast for a few years and this particular lesson marked the first time I grappled successfully with dew point, relative humidity, altitude, air parcels, and formation of the cloud base. The mountain examples along with the supplement to this lesson really made certain in my mind the meaning of lapse rates. And the bonus was actually calculating cloud bases and heights. I have a camera pointed skyward (currently to the west at an elevation of 30 degrees) and Python code that captures an image every ~20 seconds. I have had marginal success building a neural network model to predict probabilities of what is in the camera view. It is still flawed. However these lessons are spinning some gears upstairs on how I can take this new knowledge and do something even more interesting. Thanks again.
Thanks! I'm not a programmer but am currently struggling to learn Python. Well...a flavor of Python called CircuitPython....but that is a cool project to take pictures at certain intervals.
@@MelStrong I wasn't familiar with CircuitPython. I have used Python on my collection of Raspberry Pi to collect weather data from a sensor board as well as a screen capture of the sky. Are you intending to interface with some boards using Python?
@@cppprogramming Mostly trying to build some interactive devices/exhibits, though if I got good enough I'd like to be able to gather data from various sensors.
@@MelStrong I used the Sense HAT for the Raspberry Pi. It sits on the PI3 and measures temperature, pressure, humidity, along with all the intertial measurements (angular rates and accelerations). The inertial data can correlate indirectly I think (vibrations) to wind speed. Although I did not persure that. Here's my rig including the vertical facing IP camera. instagram.com/p/B64dBr8gLIc/
Great clarity of presentation and excellent illustrations like the case of a bird! Feel grateful to you Sir!
Wonderfully clear presentation. Thanks!
Exceptional Explanation Mel!
Great job! Really easy to understand it all , thank you for the video!
Thank you for your nice comment!
Well done good and faithful weatherman.
one of the best videos of youtube
Amazing lecture, I wish I could know it ealier. Thanks
This is a knowledge Vault
Thank you for posting this series! You do a wonderful job of explaining the processes and your demonstrations r on point!
3:07 Fly ash mostly isn't carbon soot like from a candle flame. It's whatever else was in the coal: silica, alumina, lime.
I've enjoyed this lecture a lot, learned so many things I didn't know!
These lectures are absolutely fantastic, you are a great teacher. I’m a chemical engineer and it’s great to put all the thermodynamics, heat transfer, unit operations etc. knowledge into understanding the nature around me. The only con is the use of imperial units which are retarded by definition, but well, it’s MURICA 😂 thank you heaps Mel!
Thanks so much Mel, we highly appreciate this I'm, for the first time I'm fully understanding cloud formation. I'm writing my drone instructor exam soon and one of the presentations I need to do is on Meteorology.
Hi
Please put more video about meteoroligy ,it has been really helpful
Such a brilliant explanation!:)
Great content with very well explanation.
Thanks sir
Thanks for your comments!
I like this it's a good one for while I eat my big slow daily dinner (I'm retired due to the miracle of aging).
Gosh these are sooo good! Thank you!
Fantastic content! 🔥
Thank you very muvh for another great lesson! 🙌
Never thought that making sense of the weather could be so satisfying. Feeling part of a larger human-feline Weather Appreciation Society now 🐱🌤🌨❄
3 pages of notes on this one. Thanks!
Thanks - this is just what I've been looking for. However, there is a little mathematical problem with the Butane combustion formula at the 8:00 mark - there should be 2 x Butane molecules for the equation to balance.
Yes I usually don't balance any of my chemical equations in any of my lectures because they were originally intended for a non-science audience and I didn't want to add any additional complications for them.
Omg. Suddenly I understand the difference between wet and dry adiabatic laps rates! What a build up! What a revelation! I feell like a third eye has been opened in my forehead!
Very interesting, Thanks!
Mel, thank you so much for making these available - you're doing the world a real service! Since I had more time on my hands due to lockdown, I decided I might as well learn something new. Your lectures are brilliantly informative and have inspired me to create a simple program to predict whether conditions support convection-based cloud formation. However, I'm not sure what the right method to use is. Is it more accurate to assume a parcel of air at current air temperature with a certain dew point and compare that with a 'standard' atmosphere for the time of year, or to assume a parcel with temperature equal to current surface temperature and compare that with air temperature?
Well I would start with the current temperature and dew point at the surface. You can create a formula that will calculate the new temperature of the rising air parcel at different altitudes based on the dry adiabatic lapse rate, and then onwards with the saturated adiabatic rate once saturation is reached. You would want to compare the temperatures of your parcel to the actual temperatures aloft. To do that, you could obtain recent weather balloon data. Every 12 hours weather balloons across the world go up, and you can find that data online. One place to start is the University of Wyoming archive of atmospheric soundings, which updates every day with new data (link is below). You'd want to find the sounding closest to where you live. That would give you the temperatures aloft. You could then compare your hypothetical rising plume of air and see if it would indeed continue to rise or not based on the surrounding temperatures. Then to make it more realistic, you could use the approximation that your parcel of air loses 1 degree C of dew point for every 1km it rises. This is due to the expansion of air and some mixing of drier air into the parcel. I don't do this when I am calculating clouds on paper, but it would be easy to code that in and would be more realistic. You might even be able to figure out a way to have the program automatically download the most recent weather balloon data and current temperature/dew point from your nearest weather station, and then have it calculate what it thinks will happen...then check out the sky each day to see if it is correct!
One reason that this might not work is that in some locations the weather balloon rises very early in the morning, when there is a temperature inversion at the surface. That temperature inversion goes away after the sun is up for a couple of hours, but it will mess up your math because the inversion will prevent air from rising.
weather.uwyo.edu/upperair/sounding.html
That's really helpful, thanks. If I'm allowed to take up your time (briefly) again: if my model finds that the plume of air rises, hits the dew point and continues to cool until it reaches -40C, is this a somewhat decent indicator of rain?
Thank you for these lectures!
I hope someone can help me out with this question: When warm air rises up and stops at some height (when its temperature is equal to the surrounding air), why does it sink back down it it is already in equilibrium with the surrounding air? Also, why does convection form a cycle? I can't reason out why the air moves sideways and then downwards after rising up. What determines the distance the air moves horizontally before it sinks down (what decided the horizontal size of the convection cell)?
Brilliant explanation , i realy loved it
I like your cat. Thank you for the content.
Muy muy muy buen video :) ... Me gustó mucho y me ayuda a mejorar mi listening en ingles :D ... Genial¡!
Love the part where you said because America, that's why.
One question, I see cumulus clouds always moving with the wind. Do the thermals move with them? Or does the cloud leave the thermal and starts dissipating? Amazing content thanks ☺️
Thanks for these! I'm using your lectures to help gain the knowledge necessary for my helo pilots license. I appreciate your efforts! Quick question.. Are the Adiabatic Lapse Rates based on temperature loss due to our normal temperature lapse rate (air is cooler as we go higher unless inversion) OR is it based on air expansion and temperature change due to pressure loss? Looking forward to continuing through this playlist.
The balloon representing a "parcel of air" placed inside the vacuum chamber really drove the point home about air parcels expanding with altitude. Of course, I did grimace when the balloon filled the entire chamber, expecting some sort of explosion or pop. =)
The balloon has popped on occasion when I have demoed this in class. However, since all of the air is sucked out of the chamber, the 'pop' makes very little noise. But everyone in class is holding their ears when the balloon gets big :). Strangely, it more often pops when I let the air back in - it flies around in there and then suddenly pops but I don't know what it is hitting.
@@MelStrong I wonder if the sudden temperature change with the balloon compression may be popping it? Or I suspect that the air is returned via a single port and I the air velocity may be high enough to puncture the surface much like a finger poking a bubble. I didn't hold my ears but I certainly winced. =)
@@MelStrong I assume it is due to elastic instability of balloon rubber and sudden pressure change created as air rushes back in the chamber.
Shout out to you Sir from a budding geographer from India !
Generally it is more difficult to get basic concepts across to students ; they either misunderstand or lose the flow of a topic.
However , you've explained everything very clearly in your video . Keep up the good work !
Hey Mel, Great content, well done for your work! I have one question. If rising air expands then,why do clouds have bigger flat bottoms and so much smaller tops? It's like air is siniking. Thanks
But why are we assuming that as the air parcel starts coming down all the water droplets are left behind?
In reality as soon as air starts to rise from the surface, there is air sinking down (from above) to replace it. It happens concurrently. When the rising plume of air reaches the top of the thermal or cloud, it will eventually make its way back down to the surface. There does not need to be any removal of water at all for this to happen.
HIS CATT 🥺
Don't forget cloud seeding !!! ❤
PS don't change the earths climate outta fear *cough cough @BillGates
Amazing content! I had a question, you only mentioned the dew point on surface, but wouldn’t the dew point change with altitude? Does the dew point on surface dictate when cloud developments will happen above it?
If you were to sample air around the world you would find that yes the dew point decreases with altitude. For convective cloud formation, I am using the assumption that the parcel of air rising from the surface is completely isolated (adiabatic) and doesn't mix with any of the surrounding air. In reality, there is some mixing that occurs, which does lower the dew point a little bit as the parcel ascends. Also, as the parcel expands, that lowers the dew point as well even though we aren't subtracting any water from the air (think of it as the water molecules are becoming farther apart as the air expands. I make the assumption that the dew point doesn't change as the parcel rises to make the math easier when we are plotting out where clouds might form in the atmosphere.
In general though, it is true that the higher the dew point at the surface, the lower the cloud base if temperatures are equal on comparable days.
@@MelStrong I think I've finally made sense of the way the dew point changes with altitude. Simply speaking, as we go up, the mixing ratio reduces. There are less water molecules per volume of air up there.
@@MelStrong but then, here is a question: if we were to calculate the height of the cloud base precisely, shouldn't we have taken the lowering of the dew point into consideration?
It must be a few degrees lower as we go up several thousand feet...
@@gregory.chalenko Well the main reason that the dew point is lowering as you go up is because the air that is up there has already undergone this process that I'm talking about. In order for air to get up to say 5km up in the atmosphere, it already had to rise up, expand, cool, and condensate out water, leaving it with a lower dew point than it had at the surface. An air parcel at a given height has a history - it originally came from somewhere else, and however it got there, condensation removed water from it on the way up.
When I am doing the math on calculating cloud base, I am assuming that there is no mixing and that the rising air parcel is perfectly isolated. So as that parcel rises, it is not losing or gaining water or heat from the surrounding air. That assumption is pretty close to reality - rising parcels are fairly isolated from their surroundings. However, it is true that a rising parcel of air can 'suck in' dry surrounding air, which further lowers the dew point.
If we wanted to be extra precise in our calculations, we could also account for the fact that there is a decrease of dew point in a rising air parcel simply due to the expansion of the rising air (same amount of water molecules but in a larger and larger volume). An approximation often used is that a rising parcel of air is lowering its dew point by about 1C/km simply from the expansion of air. I avoid this to make the math easier, but you could include that to make more precise cloudbase calculations.
@@MelStrong Makes perfect sense. Thanks a lot for the detailed explanation!
21:17 we are now pumping air out of this chamber
Yes to simulate lower pressure at higher altitudes in the atmosphere.
In the video you say „we are now pumping air out of this balloon“ but I believe you meant to say you are pumping it out of the chamber.
Hi Mel Strong,
I was wondering if you teach at a university… if so, which one?
ps: love your content!
UA-cam on the climate change bit has a caption saying that ‘climate change is mainly caused by humans’ …mainly is the word they chose…my goodness. I believe even you know that’s a little over the top. Lol
18:33 my godness it looks like a stone sitting in front of you hhahahahahah
because America ,that's why. hahahahaha