radio wave propagation book and lecture notes

Thunder and explosions also create pulse waves. A pulse wave is a sudden disturbance in which only one wave or a few waves are generated, such as in the example of the pebble. If you drop a pebble into the water, only a few waves may be generated before the disturbance dies down, whereas in a wave pool, the waves are continuous. Ask students to give examples of mechanical and nonmechanical waves. If you put a cork in water that has waves, you will see that the water mostly moves it up and down. If you feel yourself being pushed in an ocean, what you feel is the energy of the wave, not the rush of water. The energy moves forward through the water, but the water particles stay in one place. In reality, however, the particles of water tend to stay in one location only, except for moving up and down due to the energy in the wave. Many people think that water waves push water from one direction to another. Water waves have characteristics common to all waves, such as amplitude, period, frequency, and energy, which we will discuss in the next section. Because water waves are common and visible, visualizing water waves may help you in studying other types of waves, especially those that are not visible. Even radio waves are most easily understood using an analogy with water waves. For earthquakes, there are several types of disturbances, which include the disturbance of Earth’s surface itself and the pressure disturbances under the surface. For sound waves, the disturbance is caused by a change in air pressure, an example of which is when the oscillating cone inside a speaker creates a disturbance. For water waves, the disturbance is in the surface of the water, an example of which is the disturbance created by a rock thrown into a pond or by a swimmer splashing the water surface repeatedly. However, light is not a mechanical wave it can travel through a vacuum such as the empty parts of outer space.Ī familiar wave that you can easily imagine is the water wave. The medium may be a solid, a liquid, or a gas, and the speed of the wave depends on the material properties of the medium through which it is traveling. Sound and water waves are mechanical waves meaning, they require a medium to travel through. Light, sound, and waves in the ocean are common examples of waves. Waves transfer energy from one place to another, but they do not necessarily transfer any mass. What do we mean when we say something is a wave? A wave is a disturbance that travels or propagates from the place where it was created.

Radio wave propagation book and lecture notes