These are the Governor-General’s Academic Medal, which have been given out annually since 1873 for the student in Canada with the highest GPA. Each of the medals have a picture of the Governor-General and their spouse on one side, and that GG’s personal coat of arms on the other.
The bronze one at the bottom was from the tenure of Adrienne Clarkson (1999-2005) and is given out to high school students. A different bronze medal is handed out to trade school students.
The silver one in the middle is from Michaelle Jean (2005-2010) and is given to university undergrads, and the golden one on top, from the current GG, David Johnston, is for graduate students.