Hot-air balloons are used as entertainment in tourist spots in Egypt, Turkey and many other countries. For the balloon to rise in the air, the balloons are filled with hot air at 90o C. Since the hot air’s density is less than the cold air’s density in the surrounding area, the balloons rise and float into the air. If they have to be kept at a particular height, the burner below the mouth of the balloon is put off. If it has to be elevated to greater height, it is started again. The balloon must have a minimum size so that it can overcome the force of pull of gravity of the Earth.
AUTHOR: Islamic Voice
Islamic Voice is a monthly Islamic magazine published in Bangalore. It is the largest English language Muslim publication in India. It is a comprehensive magazine, places a relatively high emphasis on social issues and strives to have a broad appeal. Since 1987, Islamic Voice has covered its fascinating namesake without fear or favour, with insight, accuracy, thoroughness and a well rounded perspective on a variety of subjects - be it the economy, politics, lifestyle, the arts, entertainment, travel, science, technology or health. That's why Islamic Voice is the country's most widely read publication, a position it has held for more than a decade. And that's why it makes sense to subscribe to Islamic Voice. We represents all Muslim sects and shades of thought from all over India. We focus on "our" triumphs which, mostly, go unreported as well as constructively addresses our failures and shortcomings. Editor-in-Chief: A.W. Sadatullah Khan Genre: Current Affairs associated with Muslims Subjects Covered: Human Rights I Analysis I Special Reports I Issues I Book Reviews I National I International I Newsmakers I Community News I Islamic Perspectives I Classifieds I Opinions Focus articles on: Education and Children I Inter-faith Relations I Matrimony I Muslim economy I Muslim Perspective I The Muslim world I Society I Travel I The Western viewpoint I Women in Islam Special focus on Faith and Law: Fiqh I Hadith I Quran