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 Aug 12, 2008, 10:51 PM #1 mac000 macrumors 6502a   Join Date: Sep 2005 Water Density Question Can someone please help me solve this problem: Assume for a moment that five inches of snow ended up falling at a college. Your instructor goes out to shovel his 40-feet by 10-feet driveway, which is covered in a five- inch thick blanket of white. Assuming that a heavy, wet snow fell at the college (at a snow-water ratio of 7:1), how much would the snow on the driveway weigh? Now assume a dry, fluffy, powdery snow,with a snow-water ratio of 20:1. How much would five inches of this type of snow weigh on the driveway? 0
 Aug 12, 2008, 10:53 PM #2 Chundles macrumors G4     Join Date: Jul 2005 Location: The Gong, Australia Give the question to me in metric and I'll give it a go. __________________ This is going straight to the Pool Room 0
 Aug 12, 2008, 10:56 PM #3 swiftaw macrumors 603     Join Date: Jan 2005 Location: Omaha, NE, USA So that is (40*12)*(10*12)*5 = 288000 cubic inches of snow A 7:1 snow-water ratio means that this equates to (288000/7) = 41182.86 cubic inches of water The mass of 1 cubic inch of water is 0.036127 pounds So 41182.86 cubic inches of water weighs approx 1486.4 pounds Repeat for the fluffy 20:1 ratio snow. Last edited by swiftaw; Aug 12, 2008 at 11:15 PM. 0
Aug 12, 2008, 11:09 PM   #4
oldschool
macrumors 65816

Join Date: Sep 2003
Quote:
 Originally Posted by mac000 Can someone please help me solve this problem: Assume for a moment that five inches of snow ended up falling at a college. Your instructor goes out to shovel his 40-feet by 10-feet driveway, which is covered in a five- inch thick blanket of white. Assuming that a heavy, wet snow fell at the college (at a snow-water ratio of 7:1), how much would the snow on the driveway weigh? Now assume a dry, fluffy, powdery snow,with a snow-water ratio of 20:1. How much would five inches of this type of snow weigh on the driveway?
convert everything to similar units. Let's use inches.
40' = 480"
10' = 120"

• VOLUME OF SNOW: 480*120*5 = 288 000 cu. inches

• 1 cu. inch of water becomes 7 cu. inches of snow (snow is less dense)

• (288 000 cu. in. snow)/(x sq. in. water) = (7 cu. in. snow)/(1 cu. in. water)

• CROSS MULTIPLY and solve for X

• This will give the volume of water in the driveway in cu. in. Now you have to figure out the weight of one cu. in. of water.

I just looked it up on google: Water is 0.036127 pounds/cu.in.

If the question was in metric it would be a lot easier, since at sea level, one cubic centimeter of water is equal to one gram.

Good luck.
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Aug 12, 2008, 11:11 PM   #5
swiftaw
macrumors 603

Join Date: Jan 2005
Location: Omaha, NE, USA
Quote:
 Originally Posted by oldschool convert everything to similar units. Let's use inches. 40' = 480" 10' = 120" • VOLUME OF SNOW: 480*120*5 = 288 000 cu. inches • 1 cu. inch of water becomes 7 cu. inches of snow (snow is less dense) • 288 000 cu. in. snow 7 cu. in. snow ---------------------- = ---------------- x sq. in. water 1 cu. in. water • CROSS MULTIPLY and solve for X • This will give the volume of water in the driveway in cu. in. Now you have to figure out the weight of one cu. in. of water. I just looked it up on google: Water is 0.036127 pounds/cu.in. If the question was in metric it would be a lot easier, since at sea level, one cubic centimeter of water is equal to one gram. Good luck.
Umm, I did just that above.
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Aug 12, 2008, 11:13 PM   #6
EricNau
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Join Date: Apr 2005
Location: San Francisco, CA
Quote:
 Originally Posted by oldschool If the question was in metric it would be a lot easier, since at sea level, one cubic centimeter of water is equal to one gram.
At sea level? Would that make a difference?

Temperature, on the other hand, would make a difference; one cc of water is equal to one gram at approx. 4 degrees C, I believe.
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Aug 12, 2008, 11:13 PM   #7
oldschool
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Join Date: Sep 2003
Quote:
 Originally Posted by swiftaw Umm, I did just that above.
ever think that i opened the window before you posted? i posted mine just a few minutes after yours. SORRY.

plus mine looks better with the bullet points and all.
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Aug 12, 2008, 11:16 PM   #8
swiftaw
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Join Date: Jan 2005
Location: Omaha, NE, USA
Quote:
 Originally Posted by oldschool ever think that i opened the window before you posted? i posted mine just a few minutes after yours. SORRY. plus mine looks better with the bullet points and all.
Yeah, I was never one for presentation

I could also argue that it is mass not weight that the OP is finding. Weight depends on location, mass doesn't.
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 Aug 12, 2008, 11:20 PM #9 notjustjay macrumors 603     Join Date: Sep 2003 Location: Canada, eh? So.... why are we helping do somebody's homework? :P __________________ . 0
Aug 13, 2008, 12:48 AM   #10
Abstract
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Join Date: Dec 2002
Location: Location Location
Quote:
 Originally Posted by swiftaw The mass of 1 cubic inch of water is 0.036127 pounds
Americans have to remember that to do basic maths/physics?

I quite enjoy the metric system, where density of water is 1 g/cm^3.
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 Aug 13, 2008, 09:09 PM #11 mac000 Thread Starter macrumors 6502a   Join Date: Sep 2005 thanks people, much appreciated! 0
Aug 13, 2008, 09:16 PM   #12
EricNau
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Quote:
 Originally Posted by Abstract Americans have to remember that to do basic maths/physics?
No, because in physics we use the metric system as well.
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Aug 13, 2008, 10:07 PM   #13
Contributor

Join Date: Oct 2004
Location: On the Left Coast - Victoria BC Canada
Quote:
 Originally Posted by swiftaw I could also argue that it is mass not weight that the OP is finding. Weight depends on location, mass doesn't.
I'll keep that in mind next time I'm shoveling snow on Mars.
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Aug 13, 2008, 11:28 PM   #14
Rodimus Prime
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Join Date: Oct 2006
Quote:
 Originally Posted by Abstract Americans have to remember that to do basic maths/physics? I quite enjoy the metric system, where density of water is 1 g/cm^3.
not really. My method is I remember a handful of basic things. Like 1 cm^3 happens to be 1 ml of water and also happens to be 1 gram.

From there I can easy converted around. I know a handful of basic unit conversions and it is a cake walk.

Everything can be messed around from there.

In school I had to jump around between systems all the time and I just got used to it. Mind you in my engining classes I spent most of my time in the American system but mind you the loads I was dealing with where measured in kips. Hell I still used kips today in talking about some loads but mostly everything in in tonnage.

Lastly it is not as bad as it seems you just get used to it.

Quote:
 Originally Posted by EricNau At sea level? Would that make a difference? Temperature, on the other hand, would make a difference; one cc of water is equal to one gram at approx. 4 degrees C, I believe.

no he is right. Temperature and pressure both effect the denenty of water.

Water is always approx 1 gram/cm^3 but really it = 1 g/cm^ only at STP (standard temp and pressure) which I want to say is 4C at sea level.

water is far from the ideal liquid and steam is far from being ideal gas.

Last edited by Doctor Q; Aug 14, 2008 at 12:09 AM. Reason: post merge; please use the Multi-Quote feature
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Aug 14, 2008, 12:27 AM   #15
Abstract
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Join Date: Dec 2002
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Quote:
 Originally Posted by EricNau No, because in physics we use the metric system as well.
Thank goodness there are science teachers in America, then.

But to be honest, I knew the speed of light in miles/hour before I ever knew it in km/h, but that's because I read it it in a book or something when I was 9 or 10 years old, when I didn't even know there was a US imperial system (and one that's slightly different than the one that was used in the UK....)
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Aug 14, 2008, 01:06 AM   #16
EricNau
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Join Date: Apr 2005
Location: San Francisco, CA
Quote:
 Originally Posted by Abstract Thank goodness there are science teachers in America, then. But to be honest, I knew the speed of light in miles/hour before I ever knew it in km/h, but that's because I read it it in a book or something when I was 9 or 10 years old, when I didn't even know there was a US imperial system (and one that's slightly different than the one that was used in the UK....)
That's funny, because I only know the speed of light in meters/sec.

...Having just looked it up, how can you possibly remember 670,616,629.4 mph?

Quote:
 Originally Posted by Rodimus Prime no he is right. Temperature and pressure both effect the denenty of water.
In theory, yes, but I don't believe differences in altitude would account for any change in volume. Water has a bulk modulus of over 2e+9 Pa, so it changes very little with increased pressure. All liquids, in fact, are virtually not compressible.

Quote:
 Originally Posted by Rodimus Prime Water is always approx 1 gram/cm^3 but really it = 1 g/cm^ only at STP (standard temp and pressure) which I want to say is 4C at sea level.
STP is 0 degrees C at 100 kPa, at which water is ice, making it less dense than 1 g/cc.

Last edited by Rower_CPU; Aug 14, 2008 at 01:35 AM. Reason: post merge
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