The properties of waves are introduced using time and distance graphs.
After completing this tutorial, you will be able to complete the following:
Waves of all types continually surround us. Electromagnetic waves encompass visible light, broadcast and cellular communications, and microwaves. Mechanical waves, or vibrations, are perceived as sound. Waves carry energy and travel in a specific direction. The back-and-forth motions, or oscillations, that make up a wave also have direction.
In transverse waves, the oscillations move perpendicular to the direction in which the wave travels. Electromagnetic waves and audience waves are examples of transverse waves. In longitudinal waves, the oscillations move parallel to the direction in which the wave travels. This can be visualized by laying a Slinky horizontally and pulsing one end back and forth. Sound waves are longitudinal waves; air molecules alternately compress and spread apart along the direction the sound travels. Longitudinal waves are often visually represented the same way as transverse waves.
The physics of waves is simplified by the fact that all waves share properties that allow their behaviors and characteristics to be compared. A wave has amplitude, measured as the height from the midline to the highest or lowest point. In sound waves, the amplitude corresponds to volume; in light waves, it is proportional to brightness or intensity. The distance from one point of a wave (e.g., a crest) to the next corresponding point (e.g., the next crest) is the wavelength .The wavelength is the length of one complete wave cycle or pulse. The number of complete wave cycles to pass a fixed point in a given period of time is the frequency (f) of the wave, measured in hertz (Hz). The time it takes for one complete wave cycle to pass a fixed point is the period (T). Therefore, period and frequency are inversely related.
The speed at which a wave cycle or pulse moves in space is the wave's speed, or propagation velocity (v). For electromagnetic waves, the propagation velocity is always the speed of light (3 × 108 m/s). For mechanical waves, the propagation velocity depends on the medium through which the wave is traveling.
|Approximate Time||30 Minutes|
|Pre-requisite Concepts||The learner should have knowledge of basic graphical representation.|
|Type of Tutorial||Concept Development|
|Key Vocabulary||amplitude, crest, frequency|