The Human's Guide to Life on Earth
Appendix A - Glossary
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When a plane wave (a wave that is moving in one direction only) is passed through a small opening, the wave will spread out and move is a circular pattern. See the figure.
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| When two similar wave intersect or meet, they can interfere
constructively or destructively with each other. Constructive
interference occurs when the crests of the wave are synchronized with each
other, causing a larger crest to form as the sum of the two wave
crests. When the crests are oppositely synchronized, the crests
cancel each other and leave no wave. See the figure.
(Figure of waves interfering constructively and destructively) |
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| The place from where you are measuring time and space.
A place that serves as a framework from which you can measure distances
and elapsed times. The corner of your room may be a fine reference frame
to measure the distance to the other wall of the room and the time it
takes for a glass to fall to the floor in your kitchen.
Reference frames are not special though, you could just as easily have defined the corner of the street as your reference frame or the top of the tallest building in the world. Because reference frames can be defined anywhere, there is no one special or absolute reference frame, to which all others can be referenced. Why couldn't we just move the absolute reference frame three miles to the north? |
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The scientific method is a process that scientists use to
prove or disprove a hypothesis. The process a scientist follows is
as follows:
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| Maxwell's wave equations are some of the most beautiful in
physics. They are listed here for reference.
E and B are the electric and magnetic fields of light. |
