Experiment 2.2: Area Expansion of Solids

Area expansion of solids refers to the increase in the surface area of a solid when it is heated. This phenomenon occurs because the atoms in the solid vibrate more vigorously as the temperature rises, causing them to move slightly further apart.

The simple experiment to demonstrate the area expansion of solids can be conducted using a setup like the one in this demonstration. Read on and learn more.

Three things which may happen to a body which is heated and undergoes thermal expansion are:

• An increase in length
• An increase in area
• An increase in volume

Experiment to Demonstrate the Area Expansion

Aim: To demonstrate area expansion

Apparatus: metal gauge, cylindrical metal rod, Bunsen burner

Procedure:

At room temperature, a cylindrical rod fits exactly into a hole in the side of a metal gauge, as shown in the figure below:

Figure 2.3: Bar and gauge – Superficial Expansion

Observation: When the cylindrical metal rod is heated separately to the gauge, the metal rod will no longer fit into the hole. This is because its cross-section area has increased (area expansion or Superficial Expansion).