ASAP Science tackled that question just before the 2014 Winter Olympics and the answers to the question also apply to summer events. The answers are explained in the video embedded below.
For more resources to help students learn about the Summer Olympic Games take a look at the CBC Kids Olympics page. There you will find games and word puzzles about a variety of sports including archery, soccer, swimming, and weight lifting.
Larry Ferlazzo has assembled a substantial list of resources for learning about the 2016 Summer Olympic Games. Larry started that list nearly a year ago. His list includes resources for learning about the Paralympics.