Why do doctoral students throw hats after taking pictures of graduation photo?

It is said that the hat throwing ceremony originated from Annapolis Naval Academy graduates 19 12.

Previously, the graduation ceremony and service awarding ceremony of US Navy graduates were held separately. Whether to serve after graduation is uncertain. Graduated reserve officers have to wait a long time to be awarded, some as long as two years, and even graduation is equivalent to unemployment.

19 12, the us congress signed a decree to hold the graduation ceremony together with the service award ceremony. When the graduates of Annapolis Naval Academy learned the good news, they were ecstatic and collectively threw their hats into the air, because they were ready to serve and no longer had to wear ugly alternate officer hats.

Since then, this ceremony has spread and gradually become one of the standard graduation ceremonies, just like wearing hats and robes, pulling out ears and attending graduation parties. Traditionally, hats are thrown three times in a group.