howstuffworks: Up, up and away, it’s Hot Air Balloon Day! Hot air balloons are based on a very
howstuffworks: Up, up and away, it’s Hot Air Balloon Day! Hot air balloons are based on a very basic scientific principle: warmer air rises in cooler air. Essentially, hot air is lighter than cool air, because it has less mass per unit of volume. A cubic foot of air weighs roughly 28 grams (about an ounce). If you heat that air by 100 degrees F, it weighs about 7 grams less. Therefore, each cubic foot of air contained in a hot air balloon can lift about 7 grams. That’s not much, and this is why hot air balloons are so huge — to lift 1,000 pounds, you need about 65,000 cubic feet of hot air. A hot air balloon has three essential parts: the burner, which heats the air; the balloon envelope, which holds the air; and the basket, which carries the passengers. Most hot air balloons use a wicker basket for the passenger compartment. Wicker works very well because it is sturdy, flexible and relatively lightweight. The flexibility helps with balloon landings: In a basket made of a more rigid material, passengers would feel the brunt of the impact force. Wicker material flexes, absorbing some of the energy. https://www.instagram.com/p/BU-HjP5FTnx/ Want to float away… -- source link