4B20.10 Heat one side of a glass tube loop filled with water and insert some ink. One side of a square tube filled with water is heated while ink is inserted to show the flow. 4B20.10 heating system model H-143 Heat water in a loop of glass tubing. H-144 A rectangular glass tube filled with water is heated on one side.
Permanganate crystals show flow.
A model of a heating system with an expansion chamber and radiator. 4B20.20 4B20.20 two chimney convection box Hc-1 A candle burns under one chimney in a double chimney convection box. H-139 A container has two lamp chimneys, a candle is placed under one of them. 4B20.20 two chimney convection box H-3a.2 Smoke is used to indicate convection in the two chimney box. H-140 A candle in a chimney burns as long as there is a metal vane dividing the chimney into two parts.