For demonstrating the phenomenon of thermal convection in liquids caused by temperature variation.
Consists of a rectangular shaped borosilicate glass tube (w x h), 15 x 21cm with a funnel shaped opening at the top for filling liquids. When this tube is partially filled with water and heated at one corner after adding a dye or potassium permanganate crystals or saw dust or aluminium powder, the movement of colors or particles illustrates the formation of convection currents.