ICSE Class 9 Answered

When a liquid is heated in a container, heat flows through the container to the liquid; which means that the container expands first, due to which the level of the liquid falls. When the liquid gets heated, it expands more, beyond its original level. We cannot observe the intermediate state. We can only observe the initial and the final levels. This observed expansion of the liquid is known as the apparent expansion of the liquid.
If we consider the expansion of the container also and measure the total expansion in volume of the liquid, then the expansion is termed as the absolute expansion of the liquid.

 

Real expansion of liquid = Apparent expansion of liquid + Volume expanion of the container