Rainbow flag India during the week of Amartithi (the anniversary of his death on January 31, 1969). Rainbow is used as an element of flag of Patriots of Russia (Russian: Патриоты России, "Patrioty Rossii") political party. This rainbow flag in Italy was first used in a peace march in 1961, inspired by similar multi-coloured flags used in demonstrations against nuclear weapons. It became popular with the "Pace da tutti i balconi" ("peace from every balcony") campaign in 2002, started as a protest against the impending war in Iraq. The most common variety has seven colours, purple, blue, azure, green, yellow, orange and
Rainbow explained the dependence of the strength of the colours of the rainbow on the size of the water droplets. Modern physical descriptions of the rainbow are based on Mie scattering, work published by Gustav Mie in 1908. Advances in computational methods and optical theory continue to lead to a fuller understanding of rainbows. For example, Nussenzveig provides a modern overview. Experiments on the rainbow phenomenon using artificial raindrops, i.e. water-filled spherical flasks, go back at least to Theodoric of Freiberg in the 14th century. Later, also Descartes studied the phenomenon using a Florence flask. A flask experiment known as Florence's