1. According to the law of conservation of energy, energy can neither be created nor destroyed. It can only be converted from one form to another.
2. Sound is a form of energy which produces a sensation of hearing in our ears.
3.  Production of sound requires energy to be spent.
4. A washing machine makes a sound when switched on. This is because of the vibration of its internal parts.

• The law of conservation of energy says that energy can neither be created nor destroyed. It can be converted from one form to another. For example, we can heat an object or make it cool.
• A sound is a form of energy. It is caused by various mechanisms and forces. It creates a hearing sensation in our ears.
• The sound is mechanical energy that needs a strong medium to travel and energy to be produced. 
• The electrical instruments produce sound when they are working. The sound produced by the washing machine is due to the vibrations created in the internal parts present in it.

Production of sound requires {1:SHORTANSWER:%0%Outer#Energy~%0%Internal#Energy~%0%Hearinga#Energy~%0%Modified#Energy~%100%Energy#Energy~%0%Converted#Energy} to be spent.