0
votes
0answers
22 views

Which is the most accurate way to model the fundamental atmospheric parameters of the Earth?

I need to calculate the fundamental atmospheric parameters, I mean the actual ones, this is not an exercise but a model for a real world application so I need to take account of the humidity of air. I ...
2
votes
2answers
70 views

Do we hear sounds differently on the highest mountains?

Some searching gives that above 6,000 meter altitude the air density is less than half of that at sea level. Speed of sound is about 15-20% slower and "acoustic impedance" seems to change too. Do ...
3
votes
3answers
192 views

Why $e$ in the formula for air density?

I am reading a book that says that the density of air is approximately $D = 1.25 e^{(-0.0001h)}$, where h is the height in meters. Why is Euler's number $e$ used here? Was a differential equation ...
1
vote
0answers
46 views

What kinds of reactions happen when bubbling air through water?

Mostly I have seen air bubbling used to remove impurities in the water itself, like exemplified in this course packet. This is called "Sparging," but I have yet to learn much about transfer between ...
0
votes
0answers
30 views

Help with vacuums?

Okay, here is my understanding. Please correct me if anything here is incorrect. Suppose I have a cube with a side length of ten inches. It has a surface area of 600 square inches, and at an ...
29
votes
9answers
6k views

Why can't we see gases?

I am not sure what causes gas molecules to be invisible.This question may look silly but I really want to know the story behind it.
-1
votes
2answers
173 views

Why did they used to make the mill chimneys so tall?

Why did they used to make the mill chimneys so tall? This question was asked in an Engineering Interview at Cambridge University.
2
votes
1answer
82 views

Whirlwind/tornado/dust devil in the middle of nowhere

I live in area which have many properties similar to desert. Many times when I drive by I see a whirlwind/tornado/dust devil of sand or other garbage parts. I would like to ask how this was normally ...
1
vote
2answers
260 views

Hot Air Balloons: how is the Lift related to environmental conditions?

I'd like to build a small hot air balloon big enough to carry 0.8kg (a camera). The first thing I need to know is: once I have a big enough plastic bag and a big enough source of fire, how much will ...
-1
votes
2answers
2k views

What is the difference between air pressure and atmospheric pressure? [closed]

I remember studying that air pressure and temperature are inversely proportional. Now I saw in book that "Atmospheric pressure decreases as we go higher and higher." But in height the temperature ...
0
votes
1answer
164 views

What caused Simon Faithfull's chair to fall appart?

There is an art/science video clip on youtube, by Simon Faithful, called Escape Vehicle no.6 (chair in space). It shows a simple steel office chair, tied to a weather balloon, ascending into the upper ...
11
votes
2answers
3k views

Is there an upper frequency limit to ultrasound?

Wikipedia has this diagram of the acoustic frequency spectrum: Is there an upper limit to the frequencies you can transmit through the air? Are they absorbed more and more at higher frequencies, ...
2
votes
1answer
273 views

How to calculate pressure at altitude when there is 0 temperature lapse?

To calculate pressure at a given altitude, the following formula is used: $p = p_0 \cdot \left(1 - \frac{L \cdot h}{T_0} \right)^\frac{g \cdot M}{R \cdot L}$ (the values can be found here) This ...
4
votes
2answers
145 views

The visibility of air

For pilots of gliders or sailplanes, the 'thermal' is the most important phenomena of the air. A thermal is classically described as an upward flow of air caused by ground level heating of air that ...
3
votes
3answers
133 views

Are there convective movements similar to those in clouds everywhere in the atmosphere?

I heard there were powerful convective movements in clouds which were responsible for increasing the size of water droplets or ice crystals. My question is: do the same movements appear outside of ...
3
votes
3answers
294 views

Ozone Hole in the South Pole

Perhaps this should be a chemistry question, but it seems to have physics attributes. There's a perennial ozone "hole" around the south pole created by destruction from Cl based chemicals like CFCs. ...
5
votes
3answers
1k views

Why don't different air masses mix immediately?

In meteorology, the atmosphere is considered to be divided into air masses, regions of relatively uniform temperature and humidity with fronts on their borders. But why doesn't the air from different ...
4
votes
2answers
802 views

Can extra-solar gamma rays reach the Earth's surface?

Can gamma rays of high enough energy entering our planet's atmosphere reach the surface (50% probability)? Or, in other words, is there a window for extremely high-energy gamma rays like for the ...