THERMAL EXPANSION

At the end of this chapter, you should be able to:

• Describe qualitatively the thermal expansion of solids, liquids and gases.
• Explain the effects of expansion of water on aquatic life.
• Demonstrate that solids, liquids and gases expand at different rates.
• Demonstrate how to determine the boiling and melting point of different substances.
• Explain effects of pressure on the melting and boiling points.
• Investigate effects of impurities on the melting and boiling points of substances.
• Demonstrate the effect of varying pressure on volume of a gas
• Describe the relationship between temperature and volume of a gas
• Explain the Kelvin scale from the relationship between temperature and volume.
• Demonstrate the use of the ideal gas equation to solve simple numerical problems.

Thermal Expansion contents

Generally, when heat is supplied to a body, the body increases in size. This increase in size occurs in all directions and is known as “expansion”. It can therefore be said that a body undergoes thermal expansion when it is supplied with heat energy. On contrary, when cooled, the body contracts.

If the changes are resisted, large forces are created which are sometimes useful but at other times are nuisance. According to the kinetic theory the molecules of solids and liquids are in constant vibration. When heated they vibrate faster and force each other a little farther apart. Expansion results and this is greater for liquids.