15,4 x 10,5 x 3 cm, 90 g
Due to its dark body, the airship (3 x 1 meters) absorbs the majority of the rays of the sun that fall on it. The air in the airship becomes lighter (less dense) as it warms up. The warmer air which is now lighter than the surrounding, begins to rise together with the extremely light plastic tube.
An educational experiment to explain some basic physical properties.