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Posted: 8/25/2023 12:22:26 PM EDT
[#1]
As a PADI guy that's interesting.
Thanks |
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Posted: 8/25/2023 12:30:15 PM EDT
[#2]
I really liked watching the experiment!
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Posted: 8/25/2023 12:36:01 PM EDT
[#3]
She's a Wisconsin 10
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Posted: 8/25/2023 12:39:11 PM EDT
[#4]
Its true.
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Posted: 8/25/2023 12:40:09 PM EDT
[#5]
FYI...
For every 2.3 ft of vertical water depth, the pressure increases by 1 psi. It's even more for salt water. -ZA |
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Posted: 8/25/2023 12:47:11 PM EDT
[#6]
You've see those giant steel storage tanks for oil?
The ones with a closed roof typically have an extremely low design pressure, sometimes 2" of water. Theoretically if they didn't leak, the safety relief devices were disabled, and you had enough time, you could burst them using your lungs to over pressure the steel tank. Human lungs are typically capable of generating a pressure equal to around 20" of water column. They are remarkably fragile. |
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Posted: 8/25/2023 1:02:49 PM EDT
[#7]
When I was a kid all the kids in the neighborhood would dive and snorkel and dive off the boat docks in the keys. Someone had the bright idea to bring a garden hose so we could breathe under water. I found out real quick that you cant go very deep under water and breathe through a pipe. Also garden hose isn't made for outside pressure, its meant to hold pressure in, so the hose would collapse a few feet down and shut off the air.
I once tried as an adult to breathe underwater through a 2" pool pipe open to the air. This hose is designed to not crush with a vacuum applied. I could just barely breathe at 4 feet down but I had to strain amazingly hard to do it. 5 feet would have been impossible. but I could do 4, just barely. I want to try taking my old CPAP machine out of storage and see if I can use it under water in the pool, or maybe mod it for pool use. . Mine uses a mask which covers my nose and mouth. |
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Posted: 8/25/2023 1:06:21 PM EDT
[#8]
Quote HistoryQuoted: She's a Wisconsin 10 I never had a physics teacher that cute. |
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Posted: 8/25/2023 1:19:15 PM EDT
[#9]
Quote HistoryQuoted: You've see those giant steel storage tanks for oil? The ones with a closed roof typically have an extremely low design pressure, sometimes 2" of water. Theoretically if they didn't leak, the safety relief devices were disabled, and you had enough time, you could burst them using your lungs to over pressure the steel tank. Human lungs are typically capable of generating a pressure equal to around 20" of water column. They are remarkably fragile. You're saying that huge tanks that are designed to hold a bunch of oil are only capable of holding the pressure of just a few inches of water? I don't think I am understanding what you are trying to say. |
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Posted: 8/25/2023 1:20:17 PM EDT
[#10]
Don’t breathe compressed air
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Posted: 8/25/2023 1:28:44 PM EDT
[#11]
She seems kind of geeky, but I'd like to put pressure in her ass.
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Posted: 8/25/2023 1:29:27 PM EDT
[#12]
Also, water is in fact compressible.
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Posted: 8/25/2023 1:38:43 PM EDT
[#13]
Yes, Katerina is a cutie and musically talented too.
 KATERINA VISNJIC - SERBIAN TANGO |
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Posted: 8/25/2023 1:43:22 PM EDT
[#14]
Quote HistoryQuoted: Also, water is in fact compressible. Does it boil? |
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Posted: 8/25/2023 1:50:37 PM EDT
[#15]
In Boy Scouts we did a demonstration similar to that where kids on the second story of the church poured water into a hose and lifted a patrol worth of Scouts.
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Posted: 8/25/2023 1:50:52 PM EDT
[#16]
In the fire service we called it atmospheric or head pressure. We had a standard of 5 p.s.I. Per floor to overcome head pressure, in addition to other friction loss calculations to achieve proper nozzle pressure on, say the 10th or 12th floor the pumper would be screaming.
Hence the reason you can’t pump water up 100 floors. |
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Posted: 8/25/2023 1:59:56 PM EDT
[#17]
Vacuum is more neat
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Posted: 8/25/2023 2:07:51 PM EDT
[#18]
Princeton physics and they're learning what most people learn in high school? WTF?
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Posted: 8/25/2023 2:16:09 PM EDT
[#19]
Quote HistoryQuoted: Don’t breathe compressed air Well, it has to be somewhat compressed if you are going to be able to breath it deeper than 4 feet or so underwater. If only there was a way to regulate the pressure.... |
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Posted: 8/25/2023 2:27:45 PM EDT
[#20]
Quote HistoryQuoted: Also, water is in fact compressible. Yeah it is. . It's just that it isn't so highly compressible compared to say... the the air we breathe . It's relative. I did the math then that sub imploded. I don't remember the exact numbers the sub was at but at the depth it was when it popped the water was being compressed by about 4-5% volume compared to at the surface. |
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Posted: 8/25/2023 2:37:19 PM EDT
[#21]
Quote HistoryQuoted: In the fire service we called it atmospheric or head pressure. We had a standard of 5 p.s.I. Per floor to overcome head pressure, in addition to other friction loss calculations to achieve proper nozzle pressure on, say the 10th or 12th floor the pumper would be screaming. Hence the reason you can’t pump water up 100 floors. Don't skyscrapers have tanks on the upper floors for flushing toilets and such? |
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Posted: 8/25/2023 2:38:46 PM EDT
[#22]
Quote HistoryQuoted: Well, it has to be somewhat compressed if you are going to be able to breath it deeper than 4 feet or so underwater. If only there was a way to regulate the pressure.... It has to be really compressed to breath it underwater. It has to come out at just above two atmospheres (above standard atmospheric pressure) to breath it at 66ft. Google says this is almost 30psi of pressure. I have breathed compressed air plenty of times (both in the water and out). As far as I know, it has never hurt me. It has always been regulated to breathing air pressures. |
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Posted: 8/25/2023 2:41:15 PM EDT
[#23]
If you have a plugged field tile you will see the force of water & gravity as it blows out an upward hole.
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Posted: 8/25/2023 2:42:39 PM EDT
[#24]
Quote HistoryQuoted: In the fire service we called it atmospheric or head pressure. We had a standard of 5 p.s.I. Per floor to overcome head pressure, in addition to other friction loss calculations to achieve proper nozzle pressure on, say the 10th or 12th floor the pumper would be screaming. Hence the reason you can't pump water up 100 floors. |
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Posted: 8/25/2023 2:45:03 PM EDT
[#25]
Quote HistoryQuoted: Well, it has to be somewhat compressed if you are going to be able to breath it deeper than 4 feet or so underwater. If only there was a way to regulate the pressure.... Quote HistoryQuoted: Quoted: Don’t breathe compressed air Well, it has to be somewhat compressed if you are going to be able to breath it deeper than 4 feet or so underwater. If only there was a way to regulate the pressure.... When you think about what a scuba 2nd stage regulator (the thing in your mouth) does and just how amazingly simply it is you’re amazed. Breathing at 130 feet as easy as 0 feet. It exactly matches outside water pressure and delivers air at same pressure. Outherwise your lungs implode. I’m sure you knew that on the regulate emphasis. 
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Posted: 8/25/2023 2:45:38 PM EDT
[#26]
Quote HistoryQuoted: In the fire service we called it atmospheric or head pressure. We had a standard of 5 p.s.I. Per floor to overcome head pressure, in addition to other friction loss calculations to achieve proper nozzle pressure on, say the 10th or 12th floor the pumper would be screaming. Hence the reason you can’t pump water up 100 floors. I read somewhere that to pump water up the space needle they have a plan of two pumpers in series to get enough pressure. I wouldn't want to be anywhere near those hoses. |
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Posted: 8/25/2023 2:48:25 PM EDT
[#27]
Quote HistoryQuoted: I read somewhere that to pump water up the space needle they have a plan of two pumpers in series to get enough pressure. I wouldn't want to be anywhere near those hoses. Quote HistoryQuoted: Quoted: In the fire service we called it atmospheric or head pressure. We had a standard of 5 p.s.I. Per floor to overcome head pressure, in addition to other friction loss calculations to achieve proper nozzle pressure on, say the 10th or 12th floor the pumper would be screaming. Hence the reason you can’t pump water up 100 floors. I read somewhere that to pump water up the space needle they have a plan of two pumpers in series to get enough pressure. I wouldn't want to be anywhere near those hoses. I’m sure the math on exactly what pressure is required is east. 1 atm (14.7 psi) every 33 feet roughly. |
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Posted: 8/25/2023 2:50:29 PM EDT
[#28]
Quote HistoryQuoted: You've see those giant steel storage tanks for oil? The ones with a closed roof typically have an extremely low design pressure, sometimes 2" of water. Theoretically if they didn't leak, the safety relief devices were disabled, and you had enough time, you could burst them using your lungs to over pressure the steel tank. Human lungs are typically capable of generating a pressure equal to around 20" of water column. They are remarkably fragile. The diaphragm on the vent is around +/- 15 psi. They can hold 400 barrels of water. Thats 16,800 gallons of typically salt water |
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Posted: 8/25/2023 2:56:48 PM EDT
[#29]
Quote HistoryQuoted: She's a Wisconsin 10 Was unaware Princeton University was in WI, always thought it was New Jersey. |
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Posted: 8/25/2023 3:01:00 PM EDT
[#30]
Quoted: A column of water 100' high and 1" thick has as much pressure at the bottom as a dam 100' high and hundreds of acre feet in volume. Link to video. Dad got me into snorkel/scuba diving when I was 14 or so. I asked him "why are snorkels so short?" He cut a 3' length of PVC, put a couple of elbows on it and sent me to the shallow end of the pool. I Could Not Breathe beyond about 18"! The water pressure was too great. The same concept was demonstrated when they pressure tested the fuel tanks on the Rutan Voyager aircraft. They hoisted a garden hose 50' up the side of the hangar and connected it to the fuel tank and kept adding water till the tank deformed. Yup. Same principal for why one of the units used for barometric pressure is quoted as "inches of mercury" (usually written inHg). They also tried water, initially, but water is far less dense than mercury, and 1 inHg = 13.6 inches of water column. You'd need a ridiculously long column of water for barometric pressure. |
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Posted: 8/25/2023 3:17:07 PM EDT
[#31]
Quote HistoryQuoted: Yup. Same principal for why one of the units used for barometric pressure is quoted as "inches of mercury" (usually written inHg). They also tried water, initially, but water is far less dense than mercury, and 1 inHg = 13.6 inches of water column. You'd need a ridiculously long column of water for barometric pressure. Quote HistoryQuoted: Quoted: A column of water 100' high and 1" thick has as much pressure at the bottom as a dam 100' high and hundreds of acre feet in volume. Link to video. Dad got me into snorkel/scuba diving when I was 14 or so. I asked him "why are snorkels so short?" He cut a 3' length of PVC, put a couple of elbows on it and sent me to the shallow end of the pool. I Could Not Breathe beyond about 18"! The water pressure was too great. The same concept was demonstrated when they pressure tested the fuel tanks on the Rutan Voyager aircraft. They hoisted a garden hose 50' up the side of the hangar and connected it to the fuel tank and kept adding water till the tank deformed. Yup. Same principal for why one of the units used for barometric pressure is quoted as "inches of mercury" (usually written inHg). They also tried water, initially, but water is far less dense than mercury, and 1 inHg = 13.6 inches of water column. You'd need a ridiculously long column of water for barometric pressure. I use InH2O. But for differential pressure to calculate cubic feet of gas |
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Posted: 8/25/2023 3:30:11 PM EDT
[#32]
Yep. It's another reason why water pressure and electrical voltage are analogous.
That long thin column can exert a lot of pressure, but can't do as much work as a long thick column. Volts is to pressure and Amps is to volume. |
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Posted: 8/25/2023 3:33:46 PM EDT
[#33]
Quote HistoryQuoted: When I was a kid all the kids in the neighborhood would dive and snorkel and dive off the boat docks in the keys. Someone had the bright idea to bring a garden hose so we could breathe under water. I found out real quick that you cant go very deep under water and breathe through a pipe. Also garden hose isn't made for outside pressure, its meant to hold pressure in, so the hose would collapse a few feet down and shut off the air. I once tried as an adult to breathe underwater through a 2" pool pipe open to the air. This hose is designed to not crush with a vacuum applied. I could just barely breathe at 4 feet down but I had to strain amazingly hard to do it. 5 feet would have been impossible. but I could do 4, just barely. I want to try taking my old CPAP machine out of storage and see if I can use it under water in the pool, or maybe mod it for pool use. . Mine uses a mask which covers my nose and mouth. Don't go deep. Also, it's going to smell and taste bad. lol |
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Posted: 8/25/2023 3:44:31 PM EDT
[#34]
My favorite statement about pressure: They'd be crushed to jelly at that depth!
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Posted: 8/25/2023 3:52:41 PM EDT
[#35]
I'd like to test Newton's third law on her baps
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Posted: 8/25/2023 3:56:06 PM EDT
[#36]
Quote HistoryQuoted: Was unaware Princeton University was in WI, always thought it was New Jersey. That's how much I think of northern women. |
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Posted: 8/25/2023 6:23:46 PM EDT
[#37]
Quote HistoryQuoted: That's how much I think of northern women. Quote HistoryQuoted: Quoted: Was unaware Princeton University was in WI, always thought it was New Jersey. That's how much I think of northern women. |
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Posted: 8/25/2023 6:37:04 PM EDT
[#38]
Quote HistoryQuoted: Just use a run of the mill air compressor and adapt the output to your hose. Don't forget to regulate the outlet pressure as far as you can before starting and test without it attached to your face. You can always increase it. Blowing 40 psi directly into your mouth and nostrils is going to hurt. Don't go deep. Also, it's going to smell and taste bad. lol Quote HistoryQuoted: Quoted: When I was a kid all the kids in the neighborhood would dive and snorkel and dive off the boat docks in the keys. Someone had the bright idea to bring a garden hose so we could breathe under water. I found out real quick that you cant go very deep under water and breathe through a pipe. Also garden hose isn't made for outside pressure, its meant to hold pressure in, so the hose would collapse a few feet down and shut off the air. I once tried as an adult to breathe underwater through a 2" pool pipe open to the air. This hose is designed to not crush with a vacuum applied. I could just barely breathe at 4 feet down but I had to strain amazingly hard to do it. 5 feet would have been impossible. but I could do 4, just barely. I want to try taking my old CPAP machine out of storage and see if I can use it under water in the pool, or maybe mod it for pool use. . Mine uses a mask which covers my nose and mouth. Don't go deep. Also, it's going to smell and taste bad. lol Lol! Don’t do this. I mean what could possibly go wrong? Rust in lungs is the least concern. |
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Posted: 8/25/2023 6:37:29 PM EDT
[#39]
Pressure=gravity*height* density of liquid. No one thinks physics be, but it do.
The only thing that matters is the height of the column of fluid for pressure not how wide it is. |
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Posted: 8/25/2023 6:39:46 PM EDT
[#40]
Quoted: A column of water 100' high and 1" thick has as much pressure at the bottom as a dam 100' high and hundreds of acre feet in volume. Link to video. Dad got me into snorkel/scuba diving when I was 14 or so. I asked him "why are snorkels so short?" He cut a 3' length of PVC, put a couple of elbows on it and sent me to the shallow end of the pool. I Could Not Breathe beyond about 18"! The water pressure was too great. The same concept was demonstrated when they pressure tested the fuel tanks on the Rutan Voyager aircraft. They hoisted a garden hose 50' up the side of the hangar and connected it to the fuel tank and kept adding water till the tank deformed. I have a picture of the voyager in flight, signed by the entire flight crew |
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Posted: 8/25/2023 7:15:12 PM EDT
[#41]
That is correct...does not matter how large the area is above, pressure is height dependent only.
I remember a problem we had in Fluid Mechanics in college, for a given tank height how long does a pipe with a given friction loss have to be such that no water flows out the end. |
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Posted: 8/25/2023 7:25:10 PM EDT
[#42]
Quote HistoryQuoted: FYI... For every 2.3 ft of vertical water depth, the pressure increases by 1 psi. It's even more for salt water. -ZA 2.33333_ to be precise. 28" of water column= 1 psi. |
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Posted: 8/25/2023 7:25:26 PM EDT
[#43]
Quote HistoryQuoted: FYI... For every 2.3 ft of vertical water depth, the pressure increases by 1 psi. It's even more for salt water. -ZA Working in the refineries for close to 40 years, we had thousands of instruments that needed to be calibrated...so one factor we always remembered, 400" of water = 15.025 PSI 400 / 12 = 33.33 feet 33.33 feet / 15.025 = 2.22 ft/psi I used 15.025 because that is our base at sea level, if you used the more common 14.7, then 33.33/14.7 = 2.27 ft/psi |
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Posted: 8/25/2023 7:28:16 PM EDT
[#44]
Quote HistoryQuoted: You're saying that huge tanks that are designed to hold a bunch of oil are only capable of holding the pressure of just a few inches of water? I don't think I am understanding what you are trying to say. Quote HistoryQuoted: Quoted: You've see those giant steel storage tanks for oil? The ones with a closed roof typically have an extremely low design pressure, sometimes 2" of water. Theoretically if they didn't leak, the safety relief devices were disabled, and you had enough time, you could burst them using your lungs to over pressure the steel tank. Human lungs are typically capable of generating a pressure equal to around 20" of water column. They are remarkably fragile. You're saying that huge tanks that are designed to hold a bunch of oil are only capable of holding the pressure of just a few inches of water? I don't think I am understanding what you are trying to say. |
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Posted: 8/25/2023 7:35:12 PM EDT
[#45]
Quote HistoryQuoted: You're saying that huge tanks that are designed to hold a bunch of oil are only capable of holding the pressure of just a few inches of water? I don't think I am understanding what you are trying to say. @FF208 Yes, the giant 50,000 barrel plus storage tanks, not home hearing oil tanks. Many are floating roof, but the enclosed cone roof tanks are only capable of holding a few inches of water pressure above the liquid level. The seam between the roof and the shell is typically the weak point. Remember, pressure acts on surface area and these tanks have enormous surface area. Edit to add: Take a 100' diameter tank. the surface area of the roof is greater than 1,130,973 square inches. ( I assumed a flat roof rather than a cone because I'm lazy.) An internal pressure equal to 2" of water column puts a force of 81,656 pounds on the roof. |
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Posted: 8/25/2023 7:36:22 PM EDT
[#46]
Quote HistoryQuoted: She's a Wisconsin 10 True story. I’d hit the fuck outa that, butter face and all! |
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Posted: 8/25/2023 7:38:03 PM EDT
[#47]
Quote HistoryQuoted: FYI... For every 2.3 ft of vertical water depth, the pressure increases by 1 psi. It's even more for salt water. -ZA There was a recent experiment with carbon fiber bonded to titanium that tested this.... |
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Posted: 8/25/2023 7:44:17 PM EDT
[#48]
Quote HistoryQuoted: 2.33333_ to be precise. 28" of water column= 1 psi. Water is the most dense at 4 deg C. |
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Posted: 8/25/2023 7:46:45 PM EDT
[#49]
Quote HistoryQuoted: Lol! Don’t do this. I mean what could possibly go wrong? Rust in lungs is the least concern. Yeah, bad idea. Most compressors will blow contaminants like oil, good way to get pneumonia at the least. There are special compressors called hookah made specifically for shallow diving.  Attached File |
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Posted: 8/25/2023 7:53:27 PM EDT
[#50]
 And could have been all avoided by having this in the bottom of main drain pot 
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