Who doesn’t know that anything can rise/fly in the air only if it is lighter than the air. Accordingly, a balloon rises because the gas inside it is lighter than the air outside it. The gas filled in the balloon is helium which is lighter than the air. Hot-air balloons are filled with air that is heated and made lighter the cold air outside the balloon. And we know that hot air is lighter and it rises up according to the law of convection.
In a hot-air balloon, there is a burner outside it. This burner runs on gas that come from the bottle. The air heated by the burner goes into the balloon and inflates it. It is then that passengers get into the basket that hangs from the rocking in the wind.
The rising or coming down of the balloon is controlled by turning the flame of the burner up or down. The person who flies the balloon is called a balloonist.
– helium : អេលីយ៉ូម (ជាតិឧស្ម័នម្យ៉ាង)
– rises up : ហោះឡើង
– convection : គោលការណ៍បំលាស់ប្តូរកំដៅរបស់អង្គធាតុរាវ
– inflate : បំប៉ោង
– basket : កន្រ្តក
– rocking : ញ័រ
– flame : អណ្តាតភ្លើង