Microwaves and X-Rays

    There are two frequencies of electromagnetic waves that are used commonly by people. These two types of waves are Microwaves and X-Rays. Microwaves are the more common of the two electromagnetic waves. These waves are used to heat up food and are used for some means of communication. X-Rays are commonly used to look through the human skin to see bone.

     Microwaves sit around a frequency of 2.4GHz with a wavelength of around 12.2cm. On the spectrum this sits in between radio waves and infrared light. This wavelength is perfect for heating up food. In a typical household microwave, microwaves are produced and are absorbed by certain chemicals in food. Usually this chemical is water because one side of the water molecule is positively charged and the other side is negatively charged. Because the microwaves are interacting with the water a force will act on both dipoles which in turn will cause the water molecule to rotate. Microwaves are at the perfect frequency because the time it takes for one oscillation of the microwave is about the same as it takes for the water molecule to rotate 180°. This allows the water molecules to rotate as fast as possible and to transfer kinetic energy resulting in the food heating up.

    The source of microwaves in a household microwave is from a component called the Magnetron. In the center of the Magnetron is a heated metal rod.

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When the microwave is turned on electrons pop off of the metal rod. Usually these electrons will travel in a straight path off of the rod but because of the Magnetrons design they actually spin around the metal rod. Around the metal rod is a casing with multiple cavities. Inside each cavity is a powerful magnet which creates a magnetic field. Because the electrons have both the force from the magnets and the metal rod acting on them the electrons will then zip around. This then causes the cavities to resonate and emit microwaves into the microwave. These microwaves then bounce around the inside of the oven, due to the oven being made of metal, and then heats up the food.

    X-Rays exist in a frequency range of 3×1016 Hz to 3×1019 Hz. This is a much smaller wavelength than microwaves. Because of this they are easily able to pass through many objects. This is how an X-Ray machine works. It passes an x-ray though your skin, which the waves can pass through, and produces an image on a fluorescent screen. Because human bones are much more dense than skin the bones block out the waves and the resulting image on the screen will be a silhouette of a person's bones.