I assume you are referring to a hot-air balloon. These were the first flying machines developed by man and are used these days by tourists and weather scientists, etc. The mechanism of flight of a hot-air balloon is based on buoyancy. Hot air is supplied to a balloon. We do not really heat the balloon, rather we heat the air inside it. Air heats up and since hot air is lighter than ambient cold air, it rises and causes the balloon to expand. The lighter the balloon gets (due to hot air inside), the higher it rises and when we release the hot air, the balloon descends.
Thus, the expansion of balloon, when heated, is caused by thermal expansion of the air inside the "envelope" (that is what ballooners call the balloon). When heat is supplied, air molecules get higher kinetic energy and move rapidly, thus causing an expansion of the air mass and hence the balloon.
Hope this helps.
No comments:
Post a Comment