A shopkeeper serves you cold lassi in a tumbler. By chance, the tumbler had a small leak. You were given another tumbler by the shopkeeper to put the leaky tumbler in it. Will this arrangement help to keep the lassi cold for a longer time? Explain.
Yes, this arrangement will help keep the lassi cold for a longer time.
When the leaky tumbler is placed inside another tumbler, a layer of air gets trapped between the two tumblers. Air is a poor conductor of heat, which means it does not allow heat to pass through easily.
This trapped air acts as an insulating layer that reduces the transfer of heat from the surroundings to the cold lassi. As a result, the lassi remains cold for a longer duration.
Explanation
The chapter discusses how air is a poor conductor of heat and how trapped air provides insulation. It explains that woollen clothes keep us warm because they trap air in their pores, and air being a poor conductor reduces heat flow. Similarly, the chapter mentions that hollow bricks with trapped air keep houses warm in winters and cool in summers. The same principle applies here—trapped air between the two tumblers acts as an insulating layer.
Solution Steps
Placing the leaky tumbler inside another tumbler traps a layer of air between the two tumblers
Air is a poor conductor of heat and does not allow heat to pass through easily
The trapped air acts as an insulating layer
This insulating layer reduces heat transfer from the surroundings to the cold lassi
As a result, the lassi remains cold for a longer duration