how many helium filled balloons would it take to lift me off the ground?

Question

i weight about 155 pounds

Answer 1

So, you weight 155 lb which is about 70.5 Kg.

density of Helium = 0.1786 g/L
air density is about 1.2 g/L

The difference (bouyancy) is about 1.02 g/L or 1.2 kg/Cubic Meter

Thus 70.5/1.02 = 69.02 cubic meters.

So, ignoring the actual weight of the balloons, you need about 70 cubic meters of helium.

Assuming each ballon is about a foot (30 cm) in diameter, each balloon has a volume of 4/3*PI*0.30^3 = 0.11 cubic meters.

Number of ballons = 70/0.11 = 636

It is reasonable to assume that you would need about 50% more to account for the weight of the ballons and string, so I would say you need AT LEAST 1000 ballons.

Not as easy as you thought, huh?

Answer 2

That depends on what size balloon you want to use. The web site below is where you would even start. Don't forget to add the weight of your clothing (unless you plan to be lifted up with balloons in the nude), weight of the string if known, and the weight of a light weight lawn chair if you elect to use one (recommended). Alternative method of being supported by a toy balloon: All you need is one 16 inch Qualatex or one 17 inch Tuf Tex inflated to approximately 75%. Carefully and slowly sit on top of it making sure there is nothing in your back pockets that will poke the balloon and that the surface the balloon is on contains nothing that will harm the latex as well. With a good sense of balance, you will be floating at a fraction of the cost.

Answer 3

not sure -- I think it took Lawnchair Larry about 42 or was it 45 weather balloons -- -- "Lawnchair Larry" Walters was employed as a truck driver in Southern California. On July 2, 1982, he fastened 42 surplus balloons to a lawn chair and launched from his girlfriend's San Pedro home. He carried various supplies with him as well as a CB radio and a BB gun to shoot balloons one at a time to descend. He didn't realize how powerful the buoyancy of the balloons was. When he cut a rope holding him to terra firma, he took off with such a jolt that another anchor rope broke under the stress and he shot upward so quickly that his eyeglasses flew to the ground. He floated around the L.A. basin for several hours and reached altitudes of up to 16,000 feet. According to an article in the New York Times the next day, Walters was spotted by pilots from both TWA and Delta Airlines. It was cold at 16,000 feet and he started shooting some of his balloons to descend, but dropped his BB gun and had to wait for his rig to come down on its own. He landed in a residential neighborhood in Long Beach where got tangled in some power lines, causing a power blackout. He told reporters that his weather balloon flight had been a dream of more than 20 years. Larry Walters died eleven years after his flight from what the Los Angeles Times described as a self-inflected gunshot wound.

http://www.truthorfiction.com/rumors/l/lawnchairlarry.htm

Answer 4

One gigantic balloon that holds 2325 cubic feet of helium.

To lift a 100 pound person, you'll need about 1500 cubic feet of helium in your balloon.

100 lb = 1500 ft^3

1500(100lb) + 750(50lb) + 75(5lb) = 2325(155lb) ft^3

Answer 5

hm....about.....100 i guess