Question

4. On the basis of change of density with the
change in temperature, explain how do the liquids
get heated up, when heated in a vessel.​

Answer 1

Answer:

Explanation:

Assuming that the source of heat like a gas flame is at the bottom of the vessel, the liquid in immediate contact of the heat source becomes less dense and rises upward through the cooler, denser liquid to the top (buoyancy effect). Since volume of the liquid is almost constant (keeping aside the small increase due to the expansion), cooler, denser liquid goes to the bottom, thus a convection current is set up and eventually all the liquid gets heated up. Mechanical stirring of the liquid also helps (that is many food recipes call for constant or occasional stirring of the food to prevent burning).