Sound is a form of energy that is created by vibrations and travels through mediums such as air, water, and solids. It is perceived by the human ear as audible waves with different frequencies, which we interpret as different sounds.
Sound travels in waves, which move through air molecules and cause them to vibrate. These vibrations then travel to our ears and are interpreted by our brain as sound. Sound can also travel through other mediums such as water and solids.
The speed of sound is affected by several factors, including the density and temperature of the medium it is traveling through. Generally, sound travels faster through denser materials and at higher temperatures.
Sound intensity is a measure of the amount of energy in a sound wave. Loudness, on the other hand, is the perception of sound intensity by the human ear. The higher the intensity, the louder the sound will be perceived.
The Doppler effect is the change in frequency of a sound wave as the source or observer is in motion. This means that the perceived frequency of a sound wave will be higher if the source is moving towards the observer and lower if the source is moving away. This effect is commonly heard with passing sirens or vehicles.