The pathway for the sound wave to the ear drum and the middle ear.Ī thin, cone shaped piece of tissue stretched tight across the end of the ear canal. They are quite good for hanging spectacles and sunglasses on too. Its main job is to gather sound waves and funnel them towards the ear canal. A wave with two cycles that pass a point in one second has a frequency of 2 Hz.This is the outer flap of the ear – the part you see on the side of your head. One wave-or cycle-per second is called a Hertz (Hz), after Heinrich Hertz who established the existence of radio waves. The number of crests that pass a given point within one second is described as the frequency of the wave. This is a scientific convention that allows the convenient use of units that have numbers that are neither too large nor too small. Radio and microwaves are usually described in terms of frequency (Hertz), infrared and visible light in terms of wavelength (meters), and x-rays and gamma rays in terms of energy (electron volts). All three are related mathematically such that if you know one, you can calculate the other two. This energy can be described by frequency, wavelength, or energy. The terms light, electromagnetic waves, and radiation all refer to the same physical phenomenon: electromagnetic energy. This is similar to how sunglasses are able to eliminate glare by absorbing the polarized portion of the light. In one orientation it will pass through, in another it will be rejected. Think of a throwing a Frisbee at a picket fence. In the figure above, the electric field (in red) is vertically polarized. Polarization is a measurement of the electromagnetic field's alignment. One of the physical properties of light is that it can be polarized. The particle-like nature of light is observed by detectors used in digital cameras-individual photons liberate electrons that are used for the detection and storage of the image data. An instrument that diffracts light into a spectrum for analysis is an example of observing the wave-like property of light. How an instrument is designed to sense the light influences which of these properties are observed. All light has both particle-like and wave-like properties. Photons carry momentum, have no mass, and travel at the speed of light. Light is made of discrete packets of energy called photons. First, he had demonstrated in the concrete, what Maxwell had only theorized - that the velocity of radio waves was equal to the velocity of light! This proved that radio waves were a form of light! Second, Hertz found out how to make the electric and magnetic fields detach themselves from wires and go free as Maxwell's waves - electromagnetic waves. His experiment with radio waves solved two problems. The unit of frequency of a radio wave - one cycle per second - is named the hertz, in honor of Heinrich Hertz. Heinrich Hertz, a German physicist, applied Maxwell's theories to the production and reception of radio waves. He summarized this relationship between electricity and magnetism into what are now referred to as "Maxwell's Equations." He noticed that electrical fields and magnetic fields can couple together to form electromagnetic waves. In the 1860's and 1870's, a Scottish scientist named James Clerk Maxwell developed a scientific theory to explain electromagnetic waves. This means that electromagnetic waves can travel not only through air and solid materials, but also through the vacuum of space. Electromagnetic waves differ from mechanical waves in that they do not require a medium to propagate. These changing fields form electromagnetic waves. A changing magnetic field will induce a changing electric field and vice-versa-the two are linked. Magnetism can also be static, as it is in a refrigerator magnet. Credit: Ginger Butcher ELECTROMAGNETIC WAVESĮlectricity can be static, like the energy that can make your hair stand on end. When a balloon is rubbed against a head of hair, astatic electric charge is created causing their individual hairs to repel one another.
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