This is meant to be given to the students. Part I. Importance of the Speed of Light Light travels so quickly that it seems to be instantaneous - we are normally not aware that is has a speed at all. We can think of this as a distance of 0.24 light-seconds . Light takes 1.28 seconds to travel from the Moon to Earth, and 500 seconds or 8.3 minutes to travel from the Sun to Earth. These examples give you another way of thinking about the size of the Solar System.
Astronomers thus use time to measure distances, and the scale is based on the speed of light.
When light travels through a medium such as air, water, or glass, it goes a bit slower. We'll first practice using this equation by calculating the speed of a ball thrown by one student to another. The fainter one is called a ghost . The reflected signal will be weaker, but more importantly, it will arrive a bit later, because it had to travel farther . Since it arrives later in time, it appears to be offset on the TV set.