Racing against time: All Olympic Gold's Compared over a century.

Racing against time is a great series of animations at the NY times that highlight various Gold medal performances in London versus their counterparts over Olympics Past.  For instance you can see just how much faster Usain Bolt is compared to Jesse Owen and Carl Lewis.

There are some other animations on the site looking at swimming and track and field also.

Your Kids will really enjoy taking a look at this and it is a great teaching tool for visualising mathematical Data.  Enjoy.