DAILY MISCELLANY

SCIENCE QUESTION How can we tell if a sound is coming from in front or behind when we have only two ears?

The outside of the ear, the pinna, faces forward and catches sound waves. It also has a number of curves that help the ear determine from which direction the sound waves are coming. If the sound wave is coming from behind you, it will bounce off the pinna in a different way from sound waves coming from in front of or above you. The reflection of the sound wave off the pinna changes the pattern of the sound wave in a particular way, which depends on the direction it has come from. The brain is able to tell the difference between these patterns and so can tell which direction the sound is coming from.

The human ear is less sensitive to sounds from behind the head because of the immovable, forward-facing pinna. Other mammals, such as cats, have the ability to move their ears so that they point towards the source of the noise.

WORD OF THE DAY

syncretism [ˈsin-kri-tiz-um]

The amalgamation of different cultures, beliefs or practices

Rock’n’roll emerged in the 1950s as a wondrous syncretism of African American musical forms – particularly rhythm and blues, but also gospel and jazz – and predominantly white country music, which itself had roots in both blues and folk traditions