Measuring the Speed of Light with a Microwave Oven
Katharina Falcon
Date
8th Grade
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Table of Contents
A. Abstract
B. Question
C. Hypothesis
D. Research
E. Material
F. Procedure
G. Data
H. Conclusion
I. Acknowledgement
J. Works Cited
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A. Abstract
Is there a relationship between wave speed, frequency and wave length? I do
believe that wave speed, frequency and wave length do have a relationship. While
doing this experiment I did a lot research on microwaves and microwave ovens.
In this experiment I used a microwave, microwave safe plate and 3-6 eggs. I also
had to do my research so I would understand everything in my procedure.
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B. Question
Is there a relationship between wave speed, frequency and wave length?
C. Hypothesis
I do believe that wave speed, frequency and wave length do have a
relationship.
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D. Research
While doing this experiment I did a lot of research on microwaves and microwave ovens.
In every microwave there is a high voltage system. It is supposed to generate microwave energy.
The high voltage components do this by stepping up the AC line voltage to high voltage.
Microwaves are the reason that microwaves ovens work. Like magnetrons are usually
used in microwave ovens. A magnetron is a tube that uses electrical and magnetic currents in
order to create a powerful heat output. The electromagnetic energy created from a magnetron
travels at the speed of light and is the same type of energy used in radios and televisions. A
magnetron tube has a filament in the middle which heats up when it is near a good amount of
voltage or energy. The filament gives off electrons as it gets hotter. These electrons move out in
search of positive electrodes but they go in contact with a magnetic field along the way. The
magnetic field in the magnetron goes away from the electrons. Then they become stuck in one
area and start rotating in circles. This makes more heat, as well as a supply of energy, strong and
hot enough to quickly cook an item. In the 1920’s a general electric employee, Albert Hull, was
researching vacuum tubes when he had created the magnetron. However, Hull thought of few
uses for his invention and the magnetron remained unused for another ten years.
I also did research on the wavelengths of light in a variety of metric units. One common
unit is the nanometer, which equals a billionth of a meter. The wavelengths of light in the visible
spectrum range from 400 nanometers for deep violet.
I studied about wave interference and the different kinds of wave interference. Wave
interference is something that happens when two waves meet while going along the same
medium. The interference of waves causes the medium to take on a shape that comes from the
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net effect of the medium. Constructive interference is a type of interference that occurs at any
location along the medium where two interfering waves have a displacement in the same
direction. In this case, both of the waves have an upward displacement that is bigger than the
displacement of the two interfering waves. Destructive interference is a type of interference that
occurs at any location along the medium where two interfering waves have a displacement in the
opposite direction.
During this experiment process I learned a lot about how microwaves work and what
they are. A microwave is a short radio wave. It varies from .039337 of an inch to one ft in length
Like light waves, microwaves may be reflected and is focused. Microwaves pass easily through
rain, smoke and fog, which blocks light waves. They can also pass through the ionosphere,
which surrounds the earth and blocks or reflects longer radio waves. Microwaves are well suited
for long distance, satellite and space communications and for control of navigation. People
started noticing microwaves through the use of radar in World War 2. Today, many satellite
communication systems use them. In Televisions and radio’s microwave transmissions send
programs that can then be sent via satellite’s to locations around the world. Microwaves can also
cook food in microwave ovens.
Microwave ovens are things that heat food by inserting it with radio waves. These
waves cause molecules to create heat which cooks the food in the microwave. Cooking with a
microwave takes less time than it will with an original oven. It is because ovens put the heat
directly into the food. Or the ovens cook the food from the outside to the inside. When the food
is cooked right in the oven the meats and vegetables contain all the natural juices. Microwaves
are produced in a microwave oven by an electronic vacuum tube called a magnetron. In most
such ovens, These waves travel through a metal chamber.
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In this project I also did research on what a wave is like. A wave is like a disturbance
That goes through a medium from one location to another. A medium is something that carries
the wave. The medium is not the wave and it doesn’t make the wave. To understand the nature of
a wave it is important to consider the medium as a collection of interacting particles. The
frequency of a wave refers to how often the particles of the medium vibrate when a wave goes
through a medium. The quantity frequency is often confused with the quantity period. Period
refers to how long it takes to do something. The period of a wave is the time for a particle on a
medium to make one complete vibration cycle. Frequency and period are different but related,
quantities. Frequency refers to how often something happens. Period refers to how long it takes
for something to happen. Speed, speed is a scalar quantity which refers to “How fast something
is going.” Speed is often thought of as how much time it takes to go over a distance. An object
with no movement at all has no speed.
When I use the radio, TV or use the microwave you are using electromagnetic
waves. Radio, Television and microwaves are all things that use electromagnetic waves. They
are different from each other in wavelength. Wave length is the distance between one wave crest
to the next. Waves in the electromagnetic spectrum vary in size from very long radio waves the
size of buildings, to short gamma rays smaller than the nucleus of an atom. Electromagnetic
waves cannot be described by their wavelength but by their energy and frequency. Energy,
frequency and wave length are related to each other mathematically. The electromagnetic
spectrum has long wavelengths and short wave length.
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E. Materials
In this experiment I used a microwave oven, microwave safe plate, 3-6 eggs, ruler
and a calculator.
F. Procedure
First do your background research. Next go to the microwave oven if it has a rotating
plate remove it because it will not be able to detect the “hot spots”. Then crack an egg
and then spread out the egg white. Allow the egg white to drown in a bowl, and hold
the yolk back in one half of the broken shell. Next pour some of the egg white in a
microwave safe plate. There should be puddles or stripes of egg white that are at least
12 cm in diameter in length. Sample over the largest area possible. Next put the plate
in the microwave oven, close the oven door and cook the egg. Put it to cook for 30
minutes. The egg has to be partially cooked in some areas and almost completely
cooked in other areas. Then use oven mitts to take the plate out of the oven be careful
not to move the egg on the plate and let the plate cool. Measure the spacing between
the cooked parts of the egg. Then clean the plate and repeat the experiment 3 times.
Then look on the back of the microwave to find the frequency of the microwave
radiation the oven produces. Then calculate the speed of the microwave using the
wave length measured and the frequency of the oven.
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G. Data
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H. Conclusion
In my experiment I figured out that my hypothesis was right. Wave Speed,
frequency and wave length did have a relationship. My experiment was extremely
interesting because I saw how the egg changed and how it reacted to
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I. Acknowledgement
I would like to acknowledge my parents for spending their time and money to
help me with this project. To Mrs. Duron that helped me with my essay. To coach
Duron who let me go to the computer lab. To Ms. Morrison who made sure that I
got everything done on time. To Ms. Benjamin for teaching me how to use the
wiki. I would also like to thank God for creating all the things on the Earth
because without the things that he created I wouldn’t be able to do this project.
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J. Works Cited
“Interference of Waves.” The physics classroom.Web.25 Jan 2012. http://www.physics
classroom. com
“The electromagnetic spectrum.” Science. Web Jan.2012 < http://Science.com>
“The Magnetron Used in Microwave Ovens: Structure and Operation.” Welcome to the Gallawa
Family Web Site.Web.25 Tan.2012.
“What Is a Magnetron?” Wise Geek: Clear Answers for Common Questions Web 25.2012.
http://www.wise geek.com/what-is-a-magnetron.htm