What are the effects of thermal energy?

 Thermal energy can have different effects.

It can change a solid to a liquid: Melting.




It can change a liquid to a gas: Evaporation.

Thermal energy can cause chemical changes. 
These changes are permanent, so they cannot be reversed.

Also, thermal energy causes molecules to vibrate. As a result, the material expands.  (Expansion.)

Watch this video to see an example of expansion. 

And going back to our lesson on how heat travels: one more example of convection currents: warm air rises!