Zack Higgs
Move 1: What is an Electromagnetic wave?
An electromagnetic wave is a combination of a magnetic wave and electric wave. The magnetic wave oscillates on the x-axis and the electric wave oscillates on the y-axis.
As seen below, electromagnetic waves are sine waves that have different frequency spectrums. The radio wave spectrum is widely known and is used in WiFi, cell phones, and in the RC hobby. Radio Waves have a frequency of about 10,000Hz to about 100,000,000Hz. There is a wide range of frequency so radio waves can be applied and used in many ways. Next, when increasing in frequency, the frequency spectrum is called microwaves. Microwaves can be used for a number of things, for example: when wireless communications were first being developed microwaves were used to communicate instead of radio waves, but more commonly it is now used as a heating device we all use called the microwave. Next is infrared, which is used in most households in remotes for TVs, music devices, and other technology that needs a remote. Infrared is more commonly abbreviated “IR”, this works on a similar principle as radio waves, but tends to use a different type of wave than radio. One of the most important frequencies of radiation is visible light. As seen in the diagram above it’s, frequency range is the smallest, at about 1 X 1014. But this frequency range houses every color that we see with our eyes, at the higher frequencies we see blue to violet at a smaller wavelength of about 400nm (nanometers). At the lower frequencies we see red at about 700 nm, and as the frequency drops, it reaches into the infrared radiation. As seen below toward the middle there is green and yellow of about 550 nm produces the greens and yellows. Our eyes are like electromagnetic antennas that absorb the light that reflects off each object. When the sun reflects on our surroundings, each object will reflect at a slightly different frequency, and our eyes see that as color. Ultraviolet radiation is what causes sunburn on a sunny day and can lead to mutation of the skin and finally to cancer. After ultraviolet radiation comes X-Rays which have a wavelength of 1 X 10-14, so that is 0.000000000000001 of a meter. This is what radiologists use to examine your leg when you break it. When you are exposed to the X-Rays for a small time, the waves travel through your skin and other organs but are absorbed by your bones. Then moving into gamma rays, which have a wavelength of 1X10-21to 1X10-24, these waves will kill you.
A basic principle in electronics is that when a current is applied through a wire it induces an electromagnetic field. The electromagnetic field “sends a wave outward from the wire. When the current is removed, the field collapses which again sends a wave” . The basic way a wave is created is an object vibrating in space and time. An example is when you drop a rock in the water and the water ripples outwards. When you quickly turn the power to the wire on and off at high speeds it creates a series of waves in the plane of the wire (this wire is the antenna), in turn, creating a wave. This is equivalent to clapping your hands one per second, because 1Hz is equal to one oscillation per second, and you would be broadcasting a frequency of 1Hz. In this case, the wire is your hand, and the clap is equal to the electrical signal from a power source. Every transmitter operates on this same principle of creating a signal based on how many times it is powered in one second. That signal has a frequency based on how many times that save oscillates. When looking at a simple antenna, the antenna would consist of a bare wire and a shielded wire. This type of antenna is called a monopole antenna. After the signal has radiated from the antenna it can be used to send a signal to a receiving antenna with the same length of wire.
