Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: Weight of air

Learn more physics!

Most recent answer: 03/08/2011
Q:
How can I figure out how many pounds one cubic foot of air weighs?
why people cheat marriage affairs how many people cheat
hillcrest abortion clinic stories of abortion live abortion video
the best android phone link phone tracking apps
the best android phone mealmixer.com phone tracking apps
internet drug coupons coupons for prescription medications prescription coupon
discount card prescription site print cvs
rite aid prescription transfer coupon open coupon rite aid
imitrex 50mg thepoliticalsword.com flagyl 200mg
prescription drugs discount cards link coupons for viagra printable
can i take escitalopram in the morning can i take escitalopram in the morning can i take escitalopram in the morning
lisinopril and energy drinks lisinopril and energy drinks lisinopril and energy drinks
cialis dosage and cialis dose for copd pts
viagra bestellen online viagra pillen kruidvat pillen kopen
where buy viagra online http://viagraforsaleuk1.com online viagra buy
cialis coupons from lilly coupon for free cialis coupons for prescriptions
cialis manufacturer coupon cialis discounts coupons prescription drug coupons
venlafaxine gewichtstoename idippedut.dk venlafaxine fk
sildenafil pfizer link sildenafil sandoz
trental cena link trental nuspojave
trental cena trental trental nuspojave
how expensive is an abortion link abortion clinics dallas tx

- Kathy (age 16)
Syracuse
A:
There are several ways you can do this:

1) (easiest) -- look it up in a book. My CRC Handbook of Chemistry and Physics gives the density of dry air at 20C at 760 mm of mercury (one atmosphere of pressure) to be 1.204 milligrams per cubic centimeter. I'll leave it to you to convert to pounds and cubic feet. The density of air depends on pressure and humidity.

2) You can weight it on a scale. But be very careful about this! If you fill a container (ball, balloon) with air and put it on a scale, you are measuring the weight of the ball plus the weight of the air, *minus* the weight of the volume of air that's displaced by the inflated ball (this is the buoyant force). The buoyant force is quite noticeable if you put helium in a balloon, because the total weight of the helium plus the balloon minus the buoyant force can be negative.

You could take two equally heavy metal containers (check with a balance, and you can add small weights on one side if they aren't equally heavy). You can measure their weight difference on a balance (again, by adding weights to one side until they balance out), when one container has air in it and the other has a vacuum. But then the tricky part is getting a vacuum in one of the containers.


(Maybe you could weigh a vacuum-packed can of nuts, then open the lid a bit and weigh it with air inside. You could figure out the air volume by seeing how much water you have to pour in to fill the can to the brim. Then dry off the nuts quickly, since they're too good to waste. I'm guessing that the initial vacuum is pretty good. / mbw)

An alternative is to put two atmospheres worth of pressurized air into one container and one atmosphere of air in the other and then the weight difference will be what you want.

You can go back to the balloons -- inflate one balloon with air and one with helium and find their difference in weight (you'll have to tie the helium balloon to the scale however), and you'll still need the density of helium to get your final answer.

If your container is special with a piston which can be moved in and out and held there (maybe you can do this with screw threads), you can put one atmosphere of air in a two cubic-foot container, weight it, and then squeeze the air inside down to one cubic foot and weigh that. The container and the air inside will weigh the same, but the difference in the buoyant force will be the weight of one cubic foot of air.

Can you think of any other ways to do this?

Tom J.
hillcrest abortion clinic abortive live abortion video
best android spy spy on mobile how to spy on an android phone
buy sildenafil 100mg viagra without a doctor prescription viagra 100 mg
priligy 30mg bistromc.org cialis 40mg
levaquin pill cephalexin 250mg furosemide pill
finasteride sigridw.com cialis 80mg
finasteride zithromax cialis 80mg
online discount pharmacy dotnetblogengine.net coupon for prescription
free viagra samples coupon gallaghermalpractice.com viagra 2016 coupon
pfizer coupons for viagra prescription coupon viagra discounts coupons
manufacturer coupons for prescription drugs online viagra coupons coupon prescription
lisinopril and energy drinks lisinopril and energy drinks lisinopril and energy drinks
cialis dosage and cialis dose for copd pts
diabetes affect sexuality open diabetes sexuality treatment
acheter viagra pas acheter viagra pas acheter viagra pas
where buy viagra online side effects from viagra use online viagra buy
cialis price online open cialis price history
discount prescription drug cards open prescription discounts cards
claritinekombo read claritine za psa
naproxennatrium click naproxen migraine
fusidinezuur kopen fusidinezuur kopen fusidic acid
cialis cialis cialis walgreen coupon
cefdinir red stool cefdinir nedir cefdinir nedir
prescriptions coupons emergent-ventures.com drug prescription card
trental cena trental trental nuspojave
how expensive is an abortion link abortion clinics dallas tx

(published on 10/22/2007)

Follow-Up #1: weighing air

Q:
My son and I are working on this for his science fair project. Our attempts to fill a 1liter Gatorade bottle with air from a bicycle pump (we put an inner tube valve on the lid) and weigh it against an 'empty' bottle on a homemade balance scale failed catastrophically when the bottle exploded from too much pressure. It just occurred to me that my next door neighbor is a scuba diver. Maybe we could go to her workplace and ask to weigh an empty canister, then weigh it after it has been filled. What do you think? I think failure and the questions it brings is the most fun part of an experiment, but my son is losing his enthusiasm for the project.
why people cheat infidelity signs how many people cheat
hillcrest abortion clinic stories of abortion live abortion video
the best android phone how to spy on cell phones phone tracking apps
married woman looking to cheat My wife cheated on me most women cheat
types of abortions the weeks of pregnancy what happens when you get an abortion
types of abortions site what happens when you get an abortion
free prescription cards go walgreens prints coupon codes
discount card prescription damske.com print cvs
diprolene go furosemide 40mg
viagra coupons from manufacturer liberitutti.info drug discount coupons
coupons prescriptions prescription savings cards manufacturer coupons for prescription drugs
can i take escitalopram in the morning link can i take escitalopram in the morning
can i take antabuse and naltrexone can i take antabuse and naltrexone can i take antabuse and naltrexone
where buy viagra online http://viagraforsaleuk1.com online viagra buy
cialis price online link cialis price history
cialis price online link cialis price history
prescription drug coupons cialis coupons from lilly drug coupon
drug discount coupons blog.suntekusa.com discount coupons for prescriptions
discount prescription drug cards nationalautocare.com prescription discounts cards
naproxennatrium zygonie.com naproxen migraine
venlafaxine gewichtstoename read venlafaxine fk
ibuprofen rapid ibuprofen spc ibuprofen
flibanserin online lasertech.com flibanserin buy
flibanserin online flibanserin buy flibanserin buy
proscar vs propecia for hair loss proscar proscar pris
seroquel 25 mg read seroquel debljanje
prescriptions coupons coupons for prescriptions drug prescription card

- Marilyn Corbin (age 50)
Ventura
A:
Yeah, exploding bottles can be alarming. I think that your final weight should be taken with atmospheric pressure inside. That way you can start with either vacuum or high pressure inside and just open a little leak to atmosphere to see the change. Starting with atmospheric pressure and then pumping air in or out means too much messing with the container during the experiment- not to mention nasty surprises such as you encountered when you get too far from equilibrium.

You could take that scuba tank, filled, and put it on a good scale. Open the valve a crack, let the air out slowly, and watch the weight drop. If it's say a 3 L tank filled to about 200 atm, you could see roughly a 1 kg drop, which should be easy to measure even if the tank weighs 10 kg or more.

Mike W.
why people cheat marriage affairs how many people cheat
hillcrest abortion clinic stories of abortion live abortion video
married men cheat with men why husbands cheat wifes cheat
walgreens coupons deals blog.mrwade.co.uk walgreens photo print coupons
buy sildenafil 100mg viagra without a doctor prescription viagra 100 mg
discount card prescription go print cvs
rite aid prescription transfer coupon mesutcakir.com.tr coupon rite aid
ventolin 2mg bistromc.org deltasone 40mg
pfizer coupons for viagra free discount prescription cards viagra discounts coupons
coupon for viagra viagra trial coupon viagra discount coupons online
manufacturer coupons for prescription drugs viagra 2016 coupon coupon prescription
can i take minocycline with birth control read can i take minocycline with birth control
lisinopril and energy drinks lisinopril and energy drinks lisinopril and energy drinks
cialis manufacturer coupon link prescription drug coupons
prescription drug coupons prescription discount coupon drug coupon
cialis coupon card read cialis coupons from manufacturer
lilly cialis coupon click coupons prescriptions
arcoxia 30 go arcoxia wiki
champix alkohol go champix
kamagra wikipedia click kamagra shop
buscopan hund buscopan dosierung buscopan dragees
lasix injetavel lasix efeitos colaterais lasix
singulair 4 mg granulat scottdangelo.com singulair patient information
trental cena link trental nuspojave

(published on 03/08/2011)

Follow-up on this answer.