When nearly 30 years ago Dr. Jacob Fraden invented an ear thermometer working on this second principle, the infrared light sensor was so large that he needed a narrow gold-plated reflective tube to channel the light from the ear drum to the sensor.
Whereas he had simply read a pre-prepared statement in February when making his first public appearance following the sex scandal, Woods, who has also been interviewed by ESPN and The Golf Channel since his misdemeanours came to light, now faced some truly probing questions.
When an Egyptian news channel reflecting the aims of the Tahrir Square revolutionaries introduced some light relief to the schedules, it inadvertently created a new star more popular than the news coverage.
But as sure as darkness follows the light, spam text is about to cloud the cleanest online communications channel making it that much less trustworthy and valuable.
Children's BBC presenter Angellica Bell and Channel 4 chat show host Graham Norton pushed a "red nose" plunger to light up the tower on Friday evening.
The Channel 4 show won the main Indie Award for best independent production of the year, the light entertainment prize and the new media prize for its work in bringing the internet and TV together.