square inches in a square mile = 4,014,489,600
http://wiki.answers.com/Q/How_many_square_inches_are_in_a_square_mile

x 2 miles

x 2 inches

Divided by square inches in a gallon = 231
http://wiki.answers.com/Q/How_many_square_inches_in_a_gallon

4,014,489,600 inches

times 2

I believe 2 square miles is an area of four miles, therefore the area is exponetionally increased so the equation may be...

4,014,489,600 inches squared

Which also means that the 2 inches of depth would cube the problem.

The confusion perhaps stemming from your original question, in which you asked regarding an area of two square miles?

http://en.wikipedia.org/wiki/Square_mile

[editing to add, since I didn't cotton on to the other part of your question and want to avoid a double-post]
2 inches of depth would cube the problem
No, depth is one dimension, so you only multiply in that one dimension, ie 1 inch becomes 2, so the volume is multiplied by two.

may be.../4,014,489,600 inches squared
There's 4,014,489,600 "square inches" in a "square mile". The square inches is a unit of measurement - if you were to square it again you'd end up with some strange 4-dimensional unit of measurement. Instead, you want to end up with cubic inches, by adding 1 extra dimension.

Since a depth of 1 inch means multiplying by x1, then a 1 inch depth gives 4,014,489,600 cubic inches per square mile. Multiply by 2 for 2 inch depth (since, logically, there is twice the volume)

Then multiply by the number of square miles (2 or 4, depending on what you work out), and you've got the number of cubic inches. Again using Betsy's figures, divide by 231 for gallons, and the biggest number you're going to arrive at with these figures is 139 million gallons.

140 million gallons of water sounds like a lot but plausible.

So, 500 billion is:
500,000,000,000 (if you're American)
500,000,000,000,000 (if you're European... and either-or if you're Canadian)

1.3*10^15 is
130,000,000,000,000

So snapper is either way under or way over, depending on where he is from. The profile says Michigan, so I'm leaning towards the former.

As a way of comparison to the calculation, 140 million... well:
140,000,000
It's six orders of magnitude smaller than a Great Lake, if that helps.

[This message has been edited by micmcd (edited July 01, 2009).]

[This message has been edited by micmcd (edited July 01, 2009).]

If so, the answer is 69,514,971.4286 gallons.

There's a calculator here that will give you the answer in all sorts of measures (even teaspoons: 17,795,832,685.7).

One mile = 63,360 inches, so the inputs are

63,360 inches length
126,720 inches width
2 inches height

BTW, .004328 gallons of water will fit in a 1-inch cube.

So I think Betsy is the winner.

If I say "Two inches of rain fell over a two-square-mile area," though, that's a 1 mile X 2 mile rectangle, not a 2 X 2 mile square.

I'd love to take the crown, but I can't promise anyone that I wouldn't have done the same calculation if snapper had put "two miles squared" instead of "two square miles." I like to think I would have, but like I said...I was home watching One Life to Live through most of high school.

2 miles long by 2 miles wide by 2 inches high

Was just thinking the actual runoff would be less depending on the prior level of saturation of the soil, soil retention capacity (soil type), evaporative loss back into the air, etc. Geez--I'll shut up and get back to work now, because I have no idea how you'd calculate that, and you could probably care less.

But for some reason it seems really, really interesting to me right now.

"Oh? How interesting?"

He thought for a moment. "About as interesting, I'd say, as anything I've ever looked at when trying to avoid doing something else."

Only, I just finished my dialog and have to do all that other stupid stuff. I hate transitions from one scene to another.

You know the evaporating rate and drainage equation may come in handy. Let me see...

quote:

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snapper
Member posted July 01, 2009 09:58 PM
--------------------------------------------------------------------------------
(okay, snap. Give'm what they want)
You know the evaporating rate and drainage equation may come in handy. Let me see...

My story involves a machine that evaporates sea water at an excelerated rate with a microwave beam on a blimp from a thousand feet. I am concerned that a microwave will lose its effectiveness at such a height.
Another problem I have is the blimp is used as sort of a magnet for water vapor. 140 million gallons of water is a lot. As a gas it is weightless but still has mass. If there wasn't any factors moving the cloud wouldn't be any problem but wind is always present. So at what windspeed would it be impossible to drive a cloud if the wind is blowing in a direction that runs counter to the way the blimp wants to go? 30 mph? 10? 2?

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I did a google and landed on this site
http://ask.reference.com/related/Blimp+Speed?qsrc=2892&l=dir&o=10601
It says the top speed is 35 mpg, though one can go a lot faster.
The technology involved may allow a lot faster speeds. Consider using jets instead of props. One might use a duragable instead if you want good speeds.

Are they seeding existing clouds or adding moisture to the air to create clouds? the general humidity levels will make a difference.
Also the land will have an effect. A large water source such as the great lakes or the everglades will add to the moisture and then cause rain there. Hills and mountains will cause the air to go up condense and rain down.
Two inches of rain will not stay put. In the everglades, the water moves at a half mile a day.
As mentioned before, evaporation and seeping into the land will effect the final result.
The land structure will also have an effect. the rain will flow downhill. That usually results in ditches, channels and rivers, along with lakes.
The rate of rainfall makes a diference too. Over a whole day will have a different effect than in an hour.
where the rain falls makes a difference. Over the entire area will have a different effect than at the base of the mountains.

I'm assuming since you have a blimp and a cloud it's not nimbostratus.

A single thunderstorm can drop about 125 million gallons of water
http://www.osen.org/Technologies/Lightning/tabid/194/Default.aspx
As a meteorologist, I would have a hard time believing your blimp could control a thunderstorm. Storm dynamics being what they are, I'm not sure with all the environmental factors if I'd believe your blimp could even control a smaller rain cloud, but I'll pretend for now.

So I'll assume you are creating a smaller cumulonimbus. And here are some things to keep in mind:

Clouds are not only gas. Are you in the tropics? If so, you'd have a warm cloud with water droplets. If not, you'd have ice.

There is no proof that cloud seeding works. Having said that, in order to generate a cloud and rain you would need a source of condensation nuclei.

You won't be able to create a cloud without a source of vertical motion. I don't know the specifics of your blimp, but I don't think your blimp "magnet" alone is enough for that. Your water/ice particles need to collide in order to form precip.

quote:

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So at what windspeed would it be impossible to drive a cloud if the wind is blowing in a direction that runs counter to the way the blimp wants to go? 30 mph? 10? 2?

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I think you need to consider the role your wind is playing in the generation of this cloud before you can even hope to attempt to answer this question.