I’ve been having no a tough time grasping this concept. The dry line scenario makes sense. I’ve never really understood them, but I don’t live in an area with them, so I’ve never really dove into it. I live in western Washington and my real world experience with this concept is that clouds are associated with cool temps, which is why I would think moist air is more dense. Clouds are heavy, but they “float” on the denser cooler layer, that’s why they have those flat bottoms. They’re like a dollop of whip cream (at least the pretty fair weather cumulus) I’ve always used the fact that cold air is denser than warm air to explain thermal currents. I guess in most weather, this can double up. Cold and dry would be your heaviest, and warm and moist would be your lightest. This really helps drive home the concept of thunderstorms when you think about a pool of warm and moist air getting “pinched” between two cold and dense layers. Like a helium balloon, that pool of air is going to want to rise. Once it starts it can cause a chain reaction, which in satellite looks much like water boiling.
Thank you soooo much . I was breaking my head reading my text book . it just mentioned that increase of moisture , decrease in density . thanks a lotttttt . loved it .!!!!
Thanks for the video, great job!!!!! It did help me understand why moist air is less dense, I forgot that H20 is lighter than air, it doesn't seem like it would be but on the molecular level I guess it is.
Good effort but in the qualitative example, u need to maintain the ratio of N2 to O2 which will not change when H2O is introduced. You changed the ratio.
Soo, This is a great explanation. And I wonder if it is better to set up a dehumidifier at a higher point in my rv. Does this example mean that humid air will typically be concentrated at a higher point?
A question. Do all molecules regardless of type (O2, N2 etc) exert the same pressure against each other, ie you couldn't *add* one type of molecule more than any other to a volume of air without the volume of air expanding out against neighbouring air? From a kinematic energy viewpoint, all molecules bounce up against neighbouring molecules (according to the temperature) regardless of type? I am trying to get my head around how the density of the air changes when water evaporation increases, like say in the morning hours. There's got to be more molecules fighting to be contained in the air, right? Of course if there was a temporary increase in the number of molecules in the air it would expand into the surrounding air and be dissipated. But the pressure surely increases in a fixed volume when water is turned into water vapor? So if one geographical area has more moist air and this moist air has not yet moved away by wind or dissipated into the surrounding area's air, then wouldn't this increased number of molecules in the air *add* to the pressure? Or is it negligible compared to the increase of pressure from the increased atomic mass in the same volume? Thanks. ;)
How does this account for SIZE of molecule? It doesn't make sense that you can have the same sized space filled with 1 billion of the largest molecules in existence, or just 1 billion of the smallest molecules in existence. Different molecules habe different physical sizes and take up different amounts of physical space. Not all gas molecules have the same mass.
Heavy generally refers to weight, while dense refers to density. It is more accurate to use the word dense in this context than heavy. The opposite of dense is sparse. When talking about a substance, rather than a specific object, heavy is implied to mean the same thing as dense, and light is implied to mean the same thing as sparse. So if someone asks you, "which is heavier, steel or aluminum?", the answer would be steel, since what they really mean is "which is denser, steel or aluminum?" You could have a 1-kg block of aluminum, and a 500 gram block of steel, and that specific piece of aluminum would be heavier than that specific piece of steel. But when you aren't given enough data to know what size objects we have in mind, it is implied that you assume we have equal volumes of each, in which case it is steel in general that is "heavier" than aluminum.
Yeah, if you have equal bulk pressures and equal temperatures, the moist air parcel will be less dense than the dry air parcel. Your equation is rho=P*M/(R*T). M is the variable that is the function of the air's absolute humidity, which is 28.9 kg/kmol for dry air, and decreases slightly from there, for humid air.
Unfortunately you are wrong. Moist air is more dense and heavier--always. You are misapplying Avogadro's Law. Look at a steam table. Water is NOT a gas at these temps. Simply put, H2O is in microdroplets: Read this carefully. It shows exactly where you are mistaken: www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=8&t=16306
Very helpful. Explaining it in terms of molecular weight makes more sense now.
I’ve been having no a tough time grasping this concept. The dry line scenario makes sense. I’ve never really understood them, but I don’t live in an area with them, so I’ve never really dove into it.
I live in western Washington and my real world experience with this concept is that clouds are associated with cool temps, which is why I would think moist air is more dense. Clouds are heavy, but they “float” on the denser cooler layer, that’s why they have those flat bottoms. They’re like a dollop of whip cream (at least the pretty fair weather cumulus)
I’ve always used the fact that cold air is denser than warm air to explain thermal currents. I guess in most weather, this can double up. Cold and dry would be your heaviest, and warm and moist would be your lightest. This really helps drive home the concept of thunderstorms when you think about a pool of warm and moist air getting “pinched” between two cold and dense layers. Like a helium balloon, that pool of air is going to want to rise. Once it starts it can cause a chain reaction, which in satellite looks much like water boiling.
Wonderful explanation . Thank you sir .
Perfect explanation! Thank you very much!!
Great explanation, and easy to follow. Thanks for taking the time to teach what you know!
Thank you soooo much . I was breaking my head reading my text book . it just mentioned that increase of moisture , decrease in density . thanks a lotttttt . loved it .!!!!
Wonderfully explained
Very good presentation, You are the only one who properly explained it !!!
and now i understand why clouds are mostly high in the sky
Thanks for the video, great job!!!!! It did help me understand why moist air is less dense, I forgot that H20 is lighter than air, it doesn't seem like it would be but on the molecular level I guess it is.
is this the reason for no rain in The tropical deserts, because there is always the dry and hot air ?
Good effort but in the qualitative example, u need to maintain the ratio of N2 to O2 which will not change when H2O is introduced. You changed the ratio.
I just stumbled upon your video that was an excellent explanation very well put and understandable
Thanks for making this simple
If put on a scale which one weighs more?
In both jars fit the same amount of molecules, regardless their weight you say. So all molecules of all weights are the same size is your conclusion?
Soo, This is a great explanation. And I wonder if it is better to set up a dehumidifier at a higher point in my rv. Does this example mean that humid air will typically be concentrated at a higher point?
Yes
Excellent presentation. Helped me a lot to do my homework! ^-^
Same with me :D
thanks, very well explained
GREAT WAY TO TEACH
A question. Do all molecules regardless of type (O2, N2 etc) exert the same pressure against each other, ie you couldn't *add* one type of molecule more than any other to a volume of air without the volume of air expanding out against neighbouring air? From a kinematic energy viewpoint, all molecules bounce up against neighbouring molecules (according to the temperature) regardless of type? I am trying to get my head around how the density of the air changes when water evaporation increases, like say in the morning hours. There's got to be more molecules fighting to be contained in the air, right? Of course if there was a temporary increase in the number of molecules in the air it would expand into the surrounding air and be dissipated. But the pressure surely increases in a fixed volume when water is turned into water vapor? So if one geographical area has more moist air and this moist air has not yet moved away by wind or dissipated into the surrounding area's air, then wouldn't this increased number of molecules in the air *add* to the pressure? Or is it negligible compared to the increase of pressure from the increased atomic mass in the same volume? Thanks. ;)
EXCELLENT JON, NICE WORK
Could you share your PowerPoint with me, I would like to download it.
Nice ........ so rather than planting hay & corn , could we ( the US ) find some way to strip out the energy to drive a power plant or two .
Where can i find proof of a molecule?
NotSureIfSeriousOrJustTrolling.gif
That's why clouds form on top of air molecules. And rain when they become dense than air.
very informative , excellent and simple explanation , thumbs up :D , thanks alot :D
That is fine with me. For the record, I'm with Creighton University in Omaha, not UNL. :-)
Why can't you just add a water molecule in between the other molecules in the jar?
good stuff, best for student pilots
Hello, I would like to translate your training material into Lithuanian and post it on UA-cam. Can you give me permission?
Contact me schragej@gmail.com
EXCELLENT
That was really helpful. Thank you.
How does this account for SIZE of molecule? It doesn't make sense that you can have the same sized space filled with 1 billion of the largest molecules in existence, or just 1 billion of the smallest molecules in existence. Different molecules habe different physical sizes and take up different amounts of physical space.
Not all gas molecules have the same mass.
I have a question- Isn't there a slight difference between 'dense' and 'heavy'? I'm a bit confused. Or are they totally synonymous?
Heavy generally refers to weight, while dense refers to density. It is more accurate to use the word dense in this context than heavy. The opposite of dense is sparse.
When talking about a substance, rather than a specific object, heavy is implied to mean the same thing as dense, and light is implied to mean the same thing as sparse. So if someone asks you, "which is heavier, steel or aluminum?", the answer would be steel, since what they really mean is "which is denser, steel or aluminum?"
You could have a 1-kg block of aluminum, and a 500 gram block of steel, and that specific piece of aluminum would be heavier than that specific piece of steel. But when you aren't given enough data to know what size objects we have in mind, it is implied that you assume we have equal volumes of each, in which case it is steel in general that is "heavier" than aluminum.
can there be a situation where a moist air parcel is less dense than a dry air parcel?
Yeah, if you have equal bulk pressures and equal temperatures, the moist air parcel will be less dense than the dry air parcel.
Your equation is rho=P*M/(R*T). M is the variable that is the function of the air's absolute humidity, which is 28.9 kg/kmol for dry air, and decreases slightly from there, for humid air.
Killer explanation...Well done bro..:)
Thanks a lott
very good presentation
I just drank a Dr. Pepper... am I a doctor now too?
but steel is heavier than feathers....
Decent vid for most...a bit slow if someone has taken any chemistry classes or even just some maths...lol
Wow, you've taken a chemistry class and a math class? You must be really smart. Like REALLY smart.
Good science. But don't show the sentence "Why Humid Air Is Less Dense Than Dry Air Is" to your English teacher!
Please speak point to point
Unfortunately you are wrong. Moist air is more dense and heavier--always. You are misapplying Avogadro's Law. Look at a steam table. Water is NOT a gas at these temps. Simply put, H2O is in microdroplets:
Read this carefully. It shows exactly where you are mistaken:
www.thunderbolts.info/forum/phpBB3/viewtopic.php?f=8&t=16306
How small do these micro droplets have to be, in order to be considered water vapor? In other words, when does water vapor become micro droplets?
They're the same thing.
groups.google.com/d/msg/sci.physics/NIwQT-9O3G0/hIWNJSM4DAAJ
Ok, so micro droplets of water are the same thing as water vapor. How big can they get until they are not considered water vapor?
Read the link I sent you then restate your question. You are asking the wrong question.
Answer the question if you can.