How helium balloons would it take to lift adult person weighing around?

Question

11 stones off the ground.

Answer 1

How much does the adult weight.  Take Subway's Jared for instance.  His pre-sub weight would require maybe over 2 thousand balloons, but if you're speaking the post-sb Jared, then I'd say maybe a hundred or so. LOL

I actually have no idea!!

Answer 2

On the science programme, forgot the name. The cool one :) It took 1000 to lift a 4 year old.

So like,

a lot dude =]

Answer 3

One really big one

Answer 4

STP = Pressure of 1 atmosphere and temperature of 0 degrees centigrade.

RMM is Relative molecule mass.

Air is made up of approx 80% Nitrogen and 20% oxygen.

Average RMM of air = 0.8X14 + 0.2X16 = 14.4.

At STP 22.5 litres of air has a mass of about 14.4 grams.

At STP 22.5 litres of Helium has a mass of about 4 grams.

The lift from 22.4 litres of Helium should be about 22.5 - 4 = 18.5 grams, if we ignore the weights of the balloons.

Let us assume a balloon has a diameter of 30 cm, then radius = 15 cm.

Let us assume the balloon is spherical.

Vol of balloon = (4/3)XpiX(radius^3)

                         = 14,137 cubic centimetres

                         = 1.4137 litres.

Number of balloons in 22.4 litres = 22.4/1.4137 = 15.8 balloons 18.5 grams.

One balloon gives a lift of 18.5/15.8 grams = 1.171 grams.

11 stone = 11X14 pounds = 154 lbs = 154/2.204 kg = 69.87 kg = 69,870 grams

No of balloons

= 69870/1.171

= 59,669 balloons.

= 60,000 balloons approximately. However, I took no account of the weight of the balloons and of the string joining them to the person.

Answer: Much more than 60,000 balloons.

(Educated guess: 120,000 balloons using the lightest 'string' easily available - fishing line e.g. thin nylon)