Show Me Some Science: Air Power
How many balloons would it take to support a person? How about the wheel of a car? The LSOP puts it to the test!
What’s Going On?
Balloons have a tough job. When inflated, they balance the air atmospheric pressure on the outside with an equal pressure on the inside. At sea level this pressure is about 100 kPa or about 14 pounds per square inch. As long as you don’t poke the balloon with a sharp object or apply the pressure too quickly, they can support a lot more force than you might have guessed!
Let’s Run the Numbers!
The board on the used to hold up the car wheel is is about 1.5 square meters (about 2300 square inches). The weight of ¼ of the car is about 4,900 N (about 1,100 pounds) so the pressure in the balloons supporting the car need only be 3.3 kPa (0.5 pounds per square inch), only about 1/25 of atmospheric pressure. The balloons can easily take it!