All Questions
Tagged with everyday-life pressure
101
questions
2
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1
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101
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Why does the bottle create vacuum inside if left closed?
I'm not 100% it's correct but it has happened to me a lot of times, I always close down a bottle normally with not too much tightness, with no liquid inside, and after a day it always is so hard to ...
- 69
6
votes
1
answer
1k
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How does a bottle pour its contents?
Consider this soy sauce bottle:
The cap has two holes that are directly opposite to one another. Covering one hole, I find the soy sauce almost doesn't pour at all.
However, consider a bottle with a ...
- 318
3
votes
2
answers
132
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Why do wet napkins stick to mirrors or glass?
Take a dry piece of napkin & put it against a mirror ==> it falls down.
Dab it in water, oil, or alcohol ==> it now sticks / adheres to the mirror.
How can we explain this in physics terms? ...
- 196
2
votes
1
answer
459
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Pressure cooker becomes pressurized again after closing and opening?
While cooking food in my pressure cooker today, I pulled the whistle using my spatula to let the steam off before I opened it to check on how well cooked the food was. Before, I opened the pressure ...
- 7,980
43
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10
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5k
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When a cork is pulled out of a wine bottle, why does the inner end often expand more than the outer end?
When I pull a cork out of a wine bottle, it usually expands slightly in circumference. This makes sense: you want the cork to be slightly compressed relative to its natural diameter when it's inside ...
- 48.4k
0
votes
1
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145
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Why does a crushed bottle stay crushed if we keep a cap on it?
If one were to take a crushable plastic bottle and crush it, and, right after crushing, keep the bottle cap , the bottle would retain it's crushed state. However, if the bottle cap were not to be kept,...
- 7,980
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1
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94
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Why is a firm, inflated stand up paddle board at atmospheric?
I have a new inflatable stand-up paddle board, which is supposed to be inflated to 15 psi. I had to pump a long time and it became very rigid—and when I opened the valve it let out a lot of air. I ...
- 205
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1
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762
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Does a tire deflate more quickly when not in use and why? [closed]
Answers from a google support the obvious; that tires goes flat when not in use, but when you read the answers carefully they allude more to that - yes a tire can still go flat when not used. My ...
4
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1
answer
1k
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Why does bringing a helium filled latex balloon close to my ear make it feel pressurized?
Title pretty much says it all.
Got my son some balloons for his 1st birthday. He was playing with them while I was holding him and everytime he brought one closed to my ear it made my ear feel ...
- 141
8
votes
1
answer
882
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Why doesn't a blunt-tip nail crack the wood?
I came across this video, which shows you how to prevent the wood from cracking up at the ends while hammering a nail into it. The proposed solution is to make the nail tip blunt using a plier. This ...
- 12.5k
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1
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564
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What is causing the doors to move? [duplicate]
New to physics SE (physics too). Today I Observed a strange thing. In my house there are a pair of doors attached to same wall (the wall is about 30 cm wide), both are oppositely hinged (note: we need ...
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60
votes
2
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6k
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Why does pressure in a thermos increase after shaking up hot water and soap?
Whenever I wash my thermos, I put hot water and then some soap in; then I seal the one end with my hand or use the lid. After shaking it up, if I slowly remove the lid or my hand, it expels a little ...
- 581
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1
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152
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Keep flow rate constant from a drip container
I will be using an elevated container attached to tubing with a ball valve on the end to drip a liquid into my saltwater aquarium to help with coral growth. Conceptually it will be similar to an IV ...
- 1
4
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3
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575
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Why can human body sustain relatively high (e.g. up to 30 atm) external pressure?
I found out from the Internet that for average people it's fine to sustain up to 30 atm external pressure, for example when diving. However, given a typical human palm size of 80 cm$^2$, 1 atm means ...
- 195
2
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1
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104
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Help me understand the physics of masks
Reference: A. Konda et al., "Aerosol Filtration Efficiency of Common Fabrics Used in Respiratory Cloth Masks", ACS Nano 2020, 14, 5, 6339–6347.
The paper linked above was about ...
0
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3
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242
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How is the air pushed by the fan? [duplicate]
How is the air pushed by the fan? At first, the fan moved and the air did not move, then the air pressure increased. The air pressure increases and the air starts to move. Is my understanding ...
- 2,040
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0
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153
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Avoiding snails around potted greenery
I am not sure how a snail "sticks" to surfaces e.g. plastic pot or stone. I suspect that it produces mucus, which then adheres with molecular forces.
I would like to know, how does the ...
- 1,815
0
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2
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49
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Propagation of rate of fluid flow in a home
Suppose I have a large home with two windows. Assume the home forms a perfect seal and does not leak fluid other than from open windows.
The window in the bottom of the home is open. The window on the ...
- 103
0
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2
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5k
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Is it dangerous to put a pressure cooker under cold water after cooking?
After cooking using a pressure cooker, it usually takes a while for the pressure to be released and for the cooker to be opened. However when I think the food may have been slightly overcooked, I take ...
- 163
3
votes
1
answer
2k
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Why wind stops flowing through a window when the door is closed?
If there is a room filled with air and it had a door and a window, air only blows at a high speed through the window if the door is open. The wind stops if the door is closed. Does the air behave ...
- 141
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1
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329
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Is force due to pressure equally distributed?
Pressure is defined as: $$P=\frac{F}{A}$$
My question is what if we want to find the total force in area of $\frac{A}{2}$. Would be equal to $\frac{F}{2}$? I think that is not true unless we know that ...
- 1,648
39
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4
answers
17k
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Should a soda bottle be stored horizontally or vertically?
I am having an argument with my friend about how a nearly-full soda bottle should be stored in the fridge, with the goal of keeping the soda from going flat (i.e. keeping as much of the gas dissolved ...
- 520
1
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1
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118
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Why can't I scotchtape ice?
I am thinking that the electrostatic force (Van der Waals force) should take effect when I try to tape an ice, but the tape slips. Why does this happen?
- 13k
25
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6
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6k
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Why does low tire pressure reduce fuel efficiency?
I've always thought that it was because the frictional force on the tire was increased due to the bulging of the tires increasing the surface area in contact with the road. However, a colleague of ...
- 391
4
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2
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5k
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Why does the "air" close or open doors?
Assume we have an empty room with two doors on the opposite sides of it. If we open one of the doors, the door on the opposite side automatically closes "harder", and if we close one of the doors the ...
- 676
1
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0
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73
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How does a mister form the mist?
A mister exploits pressure difference to pull water up from the reservoir and through the outlet (Ref:https://www.explainthatstuff.com/aerosolcans.html )But what converts the water in bulk liquid form ...
- 833
0
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1
answer
36
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Sound made by trapped water
When I run water in my bathroom sink and then put the plug in whilst there is still some water left in the basin, there is a high pitch moaning or screeching noise made by my adding the plug. What ...
- 406
1
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1
answer
994
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Why does a cup on water layer create suction?
When I place a cup upside down on a layer of water, say a wet table, and I then try to lift the cup up, I can feel some resistance. So the cup is acting like a suction cup.
However the difference is ...
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-3
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2
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72
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How can the motion of the brain within the skull be stopped at the moment of impact? [closed]
How can the motion of the brain within the skull be stopped or controlled at the moment an object with velocity comes in contact with it. What type of a system would this require?
- 1,235
3
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1
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441
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Grooves on water tank
Why are there grooves on almost every water tank?
Just typing water tank in Google images would reveal what I am talking about. And here is a sample picture!
I think it would mostly be regarding ...
- 833
0
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1
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123
views
Pouring liquid out of a bottle smoothly
Can one calculate the vacuum pressure created inside a bottle when pouring liquid from it?
Glass bottle
38mm diameter orifice
- 1
5
votes
1
answer
338
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How does sharpening a pencil make it darker?
Why does a sharp pencil write better than a blunt one?
Note that the force applied on each case is identical.
- 12.5k
0
votes
1
answer
697
views
Why does a fountain pen soak ink automatically at times?
I've had a rather interesting fascination with fountain pens. The mechanism is a thing of beauty, but my attention was recently caught by a rather insignificant phenomenon which I've used a lot in my ...
- 1,630
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5
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1k
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Woodworking clamps, does force add up?
I was watching a woodworking video about glue, and the guy was clamping two pieces of wood together using a total of 8 clamps. He argued that by doing so he would apply 8 times the maximum force of ...
- 123
0
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1
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123
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is boiling point of the gas cause cooling in expansion process of refrigeration?
I have a doubt about expansion process.
Some people say it's an adiabatic expansion, but other say it's something related to the nozzle.
What is the actual cause for cooling in expansion process?
...
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1
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1
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1k
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Why does water not leak from the bag?
In the picture, the plastic bag is filled with water. The sharpened pencil penetrates through the bag. However, there is no leakage.
Could you please explain why this happens?
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1
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724
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The Mystery of the Starbucks coffee lid [closed]
If you look at a (white, opaque) Starbucks coffee lid (and the lids of many other coffee brands as well) you will see in addition to the obvious sip hole, one or more tiny perforated holes on the top ...
- 2,637
-2
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1
answer
4k
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Physics/forces involved when separating two 5 gallon buckets
So a friend jokingly said "there's no force in the universe stronger than two 5 gallon buckets that are stick together." And I thought that this has to have a wonderfully complex and scientific ...
-1
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3
answers
114
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Why is there less oxygen in a pressurised plane that is flying?
Children who have temporary lung problems like asthma attacks have to go on oxygen to heal. (At a hospital.) Immediately after a health incident they can’t go on an aeroplane because there is ...
- 861
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3
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273
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Is a well inflated tire less prone than a deflated tire to flatten due to a sharp object? [closed]
When I bought my bike, I've been told that I should make sure the tires are well inflated because this reduces the risks of having a flat tire when rolling over sharp objects, and that it was easy to ...
83
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4
answers
8k
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What causes the water in this fountain to reverse direction?
In a children's museum, I ran across this fountain. You can adjust the flow rate with a valve, visible at the bottom. At low flow rates, the sheet of water does more or less what you'd expect: it ...
- 9,765
1
vote
1
answer
222
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Holding one's breath while scuba diving
Recently when I went scuba diving, the instructor told me that it would be extremely fatal to a scuba diver to hold his breath during the dive. I searched up on the internet and came across Boyle's ...
- 3,745
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1
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80
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Why will crushing a water bottles keep the water in fizzy condition? [duplicate]
Everybody is talking only about CO2.
- 1
0
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0
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419
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What's the difference between compression by a gas/liquid or by a solid?
Atmospheric pressure is about $1atm$, that is $\approx 10^5 N/m^2$, that is, if $g = 9.8m/s^2$ we get a weight of $\approx 10.339 tons/m^2$. And yet, nobody feels like carrying 10 tons of stuff above ...
- 3,274
4
votes
1
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1k
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Boiling of Water
I studied in textbooks that the boiling point of water is the temperature at which the vapor pressure is equal to the atmospheric presssure. My doubt is since the vapor mixes with atmosphere, how can ...
- 63
3
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2
answers
324
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Why is it hard to feel sound pressure from higher frequencies?
Reading the Wikipedia page on pressure magnitudes,
https://en.wikipedia.org/wiki/Orders_of_magnitude_(pressure)
I was surprised to see that the threshold for pain (140db) is listed as ±200 Pa of ...
- 33
179
votes
2
answers
19k
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When separating an Oreo cookie, why does the cream stick to just one side only?
There is probably some reason for this, but I can't figure out what it is. I agree that it probably doesn't happen 100% of the time, but most all of the time, the cream is clinging to just one of the ...
- 2,637
1
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2
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597
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Why does a sheet of paper stick to the end of a vacuum cleaner?
What makes a piece of paper or other material hard to pull away from the end of a vacuum cleaner once it's covering the opening? What force are you acting against when you try to pull it away? Also, ...
- 113
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2
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7k
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Why plastic covers on containers are compressed when microwaved?
These situations happen a lot around me since I always bring my lunch to the school. It is not just plastic warp, but my plastic container lid too. Unlike Why does plastic wrap grow, then shrink, then ...
- 179
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0
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406
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Is it possible to breathe deep underwater with a pipe if enclosed in a box?
A problem in the physics textbook I was using asked how deep someone could go underwater and still manage to breath through a strong pipe or hose, assuming that the maximum pressure difference the ...
- 127