Loi Krathong is a festival celebrated annually throughout Thailand. The name could be translated as “to float a basket”, and comes from the tradition of making krathong or buoyant, decorated baskets, which are then floated on a river.
Loi Krathong takes place on the evening of the full moon of the 12th month in the traditional Thai lunar calendar. In the Western calendar this usually falls in November.
According to the Royal Institute Dictionary 1999, loi (ลอย) means “to float”, while krathong(กระทง) has various meanings, one of which is “a basket to be floated on water in the Loi Krathong festival”. Several translations of krathong are found, such as “floating crown”, “floating boat”, “floating decoration”. The traditional krathong are made from a slice of the trunk of a banana tree or a spider lily plant. Modern krathongs are more often made of bread or styrofoam. A bread krathong will disintegrate after a few days and can be eaten by fish. Banana stalk krathong are also biodegradable, but styrofoam krathongs are sometimes banned, as they pollute the rivers and may take years to decompose. A krathong is decorated with elaborately-folded banana leaves,incense sticks, and a candle. A small coin is sometimes included as an offering to the river spirits.
On the night of the full moon, Thais launch their krathong on a river, canal or a pond, making a wish as they do so. The festival may originate from an ancient ritual paying respect to the water spirits.
According to H.M. King Rama IV, writing in 1863, it was a Brahmanical festival that was adapted by Thai Buddhists in Thailand to honor Buddha, Prince Siddhartha Gautama. The candle venerates the Buddha with light, while the krathong’s floating symbolizes letting go of all one’s hatred, anger, and defilement. People sometime cut their fingernails or hair and place the clippings on the krathong as a symbol of letting go of past transgressions and negative thoughts. Many ordinary Thai use the krathong to thank the Goddess of Water, Phra Mae Khongkha (Thai: พระแม่คงคา).
Students brought materials to school today to create their own krathongs for Thai class to take part in the nationwide activity with the hope to build culturally sensitive students.
excerpts from: http://en.wikipedia.org/wiki/Loi_Krathong