In a longitudinal wave, the motion of the medium is parallel to the direction of the wave. This means that the particles move left and right which in turn makes the other particles start to oscillate.
The UNIA founded by Marcus Garvey has a constitution which defines red, black, and green as the Pan-African colours: red representing the noble blood that unites all people of African ancestry, the colour black for the people, green for the rich land of Africa..
1 Many in African-American communities mourn by dressing in white as a sign of resurrection and celebrate with music and hope. 2  However, Native Africans often wear red or black. 3  Black/African-Americans often express grief at death with the physical manifestation of great emotion. In some tribal cultures pipes are smoked at the gravesites. 2  In some tribal cultures, there is significance to burying people with symbolic reference to a circle. 3  In some, there is significance in non-burial, but allowing the deceased to pass on to the other world in a natural way.