Physicist Richard Feynman’s last hurrah was explaining to the American public, simply and directly, in 30 seconds, why the Space Shuttle Challenger blew up. Doing that opened up the question of why, if Morton Thiokol knew the O-ring material would be affected by the cold of that January 28 morning, did NASA decide to proceed with the launch?
http://youtu.be/UCLgRyKvfp0