Physics is in every area of life from the starry skies we see at night to the cells inside our bodies. Even what might appear to be the simplest thing is actually very complex when one looks at the details. Physics helps us understand the basics of how life operates. Microwave ovens are often used to reheat left over food, cook TV dinners and frozen foods, and to quickly heat food but is seldom recognized and understood by those who use them. People typically don’t know how a microwave oven operates, how it is structured, or how the food is actually heated.
Microwaves were first created in 1947 being 1.8 meters in height and 750 lbs created by Percy Spencer while building magnetrons for radar sets during World War II. The magnetrons would allow the radar sets to indicate where the enemy machinery was located, since the microwaves would reflect off metal. When Percy Spencer was<> working with the microwaves he noticed that a chocolate bar melted when exposed to the microwaves. Testing the capability of the microwave to cook food he used first popcorn which was successful and secondly an egg which exploded. The first microwaves, then called the Radarange, were used only in the military and for large restaurants due to their size, then the size was decreased in the 1952's and was priced $1295 which models the microwaves we see in households today.
According to Miriam-Webster's Dictionary an electromagnetic wave is "one of the waves that are propagated by simultaneous periodic variations of electric and magnetic field intensity and that include radio waves, infrared, visible light, ultraviolet, X rays, and gamma rays." What this actually means is that electromagnetic waves have both electric and magnetic fields that o...
... middle of paper ...
...g tough many people will stick a moist paper towel or napkin over the bread lockingthe moisture in and keeping it soft.
TV dinners as we all know are usually made for the microwave as well as other types of quick meal foods. These foods usually are frozen so they have a substantial amount of moisture which evaporates unneeded water, but doesn’t dry out the food as it is being cooked.
As many have heard it is not a good idea to cook an egg in the microwave, as the inside of the egg heats up it expands, however the shell on the outer surface is a solid rather than a fluid so it doesn’t expand as rapidly or as much as the liquids on the inside do therefore causing the egg shell to break. An egg shell break is not typically such a bad thing on the stove since the egg is being slowly warmed up, but in the microwave it heats up even more quickly and explodes.
We don’t have to explain about how do the objects works because we know the purpose of the objects are designed like that. For example, we know the purpose of the hair dryer which it is use to blow dry our hair. Therefore you do not need any physics principle to explain to use it, in fact you just have to press the start button to use the hair dryer.
Electromagnetic waves are waves that can propagate even though there is no medium. A magnetic field that changes with time can generate an electric field that also changes with time, and an electric field that changes with time can also produce a magnetic field. If the process is continuous it will produce a magnetic field and electric field continuously. If these magnetic fields and electric fields simultaneously propagate (spread) in space in all directions then this is a symptom of the wave. Such a wave is called an electromagnetic wave because it consists of an electric field and a magnetic field that travels in space.
Theory: Physics can be referred to as the study of various properties of matter and energy. Matter can best be described by looking at the mass of an object. Mass is the amount of material that is in an object. Mass can be found by using a spring scale, a balance scale, or an inertial balance. Inertia is the resistance by mass to any change in its state of motion. Scientific Law states that mass and inertial forces are directly proportional. The purpose of the inertial balance is to measure the different inertias between different masses therefore providing a mathematical and very accurate method of measuring mass. Experimentation showed that if a mass was put into some form of periodic motion, the mass could be measured fairly accurately by measuring the oscillation period and comparing it to a known mass period. The relationship m1=m2T12/T22 was discovered.
Bloomfild, Louis A. How things work The Physics of Everyday Life. New York: John Wiley & Sons, 1997.
The first things we learned in EGEE I thought I already knew, but I only had superficial knowledge about such things energy, heat, and radiation. For example, I thought that energy was simply the ability to work. However I learned that it is the capacity to do work (Kraushaar and Ristinen 8), generating heat, and emitting radiation (lecture 1/9/02). I also learned that the formula for energy is work = force x distance (1/9/02). Heat, we learned, is the ability to change the temperature or phase of a substance; radiation is energy emitted in the form of waves traveling at the speed of light (1/11/02). I always thought that heat was the temperature of something, and radiation was emitted from microwaves and nuclear waste. Now I know more about these things than I did before.
In 1894 Percy Spencer was born. He said when he was little he “liked to tinker and discover how things worked”. When he was 16 he went to help his family with a job at a machine shop. That job taught him how to work with electricity, so when he got older he became an electrician an Raytheon. Raytheon was the company that invented smaller radios and they had families all over America, that adopted these radios, so it was very popular. One of the later experiments that Raytheon conducted was the magnetron which made microwaves (tiny waves) to create heat. One day, Percy Spencer came near the magnetron while it was switched on, when he came near the machine he had a bar of chocolate he was carrying which melted and gave him an idea. No one knew the potential of the magnetron until the chocolate melted. (Passage
Nature of wave: It is an electromagnetic wave as it does not necessarily require a medium for p...
Radio-wave technology is one of the most important technologies used by man. It has forever changed the United States and the world, and will continue to do so in the future. Radio has been a communications medium, a recreational device, and many other things to us. When British physicist James Clerk Maxwell published his theory of electromagnetic waves in 1873, he probably never could have envisioned the sorts of things that would come of such a principle. His theory mainly had to do with light waves, but fifteen years later, a German physicist named Heinrich Hertz was able to electrically generate MaxwellÕs ÒraysÓ in his lab. The discovery of these amazing properties, the later invention of a working wireless radio, and the resulting technology have been instrumental to AmericaÕs move into the Information Age. The invention of radio is commonly credited to Guglielmo Marconi, who, starting in 1895, developed the first ÒwirelessÓ radio transmitter and receiver. Working at home with no support from his father, but plenty from his mother, Marconi improved upon the experiments and equipment of Hertz and others working on radio transmission. He created a better radio wave detector or cohere and connected it to an early type of antenna. With the help of his brothers and some of the neighborhood boys he was able to send wireless telegraph messages over short distances. By 1899 he had established a wireless communications link between England and France that had the ability to operate under any weather conditions. He had sent trans-Atlantic messages by late 1901, and later won the Nobel prize for physics in 1909. Radio works in a very complicated way, but hereÕs a more simple explanation than youÕll get from most books: Electromagnetic waves of different wavelengths are produced by the transmitter, and modulations within each wavelength are adjusted to carry ÒencodedÓ information. The receiver, tuned to read the frequency the transmitter is sending on, then takes the encoded information (carried within the wave modulations), and translates it back into the sensory input originally transmitted. Many of the men who pioneered radio had designs for it. Marconi saw it as the best communication system and envisioned instant world-wide communication through the air. David Sarnoff ( later the head of RCA and NBC) had a vision of Òa radio receiver in every homeÓ in 1916, although the real potential of radio wasnÕt realized until after World War I.
The first thing people need to understand is that microwaves are actually electromagnetic waves. Wavelengths and frequencies range from 300 MHz up to 300 GHz but, the average microwaves at home or restaurants operate at frequencies of about 2.45 GHz. Microwaves consist of a waveguide, magnetron, fan, power supply and a turntable with the base plate. These items help create the magical ability to heat our food and each have a different purpose. Magnetrons are the ones that create the waves and feeds the waveguide into the cooking chamber. Most microwaves are created in a cuboid shape and creates a chamber where it has metallic walls and so it acts like a Faraday cage which is an enclosure created by conducting material. Metal grids also cover the front door, which is made of glass, and the the light bulb cavity. Rotating turntables are also found in almost all microwaves and this helps them ensure that the food is all evenly heated.
Microwaves are last on the Pentagon’s list of worries for beam weaponry. Microwaves, in general, get only one percent of the fiscal budget. Since the microwave research and development program received only 1.5 to five billion dollars. Articles published in the 1970s criticized microwave companies for leaks and complaining the about industry had not developed safety standards. Some of the articles published were not entirely true and the public took every bit of the articles seriously. The article, “The Zapping of America: Microwaves, Their Deadly Risk and the Cover Up” was mainly about how dangerous microwaves were in the public, but there were multiple misconceptions throughout the article. High power microwaves offer advantages over lower
Convection is a transfer of internal energy into or out of an object by the physical movement of a surrounding fluid that transfers the internal energy along with its mass. According to Oxford Dictionary, convection is the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder or denser material to sink under gravity's influence, that results in transfer of heat. Two fluids are liquid and gas.The fluid above a hot surface expands, becomes less dense, and rises.This applies to objects such as steam from a hot cup of coffee turning cool, ice melting like heat moving to ice from the air, or frozen material becoming raw like how frozen food thaws more quickly under cold running water. When
In an electromagnetic wave, the constantly changing electric and magnetic fields affect each other so they both oscillate in different axis while the wave moves in a direction perpendicular to the oscillation of the fields as shown in Figure 1.
Physics can be found in all aspects of our lives and the world around us including the activities in which we find the most enjoyment. They may not be noticeable to the naked eye or even to our senses but they are there and when we become familiar with the concepts of physics then we began to ‘see’ physics everywhere.
All university students know the convenience and importance of the microwave. The microwave is particularly important for students living in the Towers, as this is their only kitchen appliance. Since microwaves are a staple for university students, they become dirty quickly. The best way to keep microwaves clean is to clean up spills immediately. If you can 't, however, do this, follow the steps below. Your microwave will be spotless again almost instantly.
Electromagnetic radiation is energy that flows through free space. Electromagnetic radiation comes in a list of energies known as the electromagnetic spectrum. Electromagnetic spectrum is the complete range of the different wavelength of electromagnetic radiation. It consists of light, radio waves, visible light, infrared waves, ultraviolet light, x-rays, microwaves and gamma rays.