Download May Term 2015

May Term 2015
Nicktae Marroquin-Haslett
5-23-15
The Absorption, Reflection, and Transmission of Light
Color is a really interesting thing to learn about. It is a bit mind-bending when you really think
about it because color is not a physical thing. We only see objects as colorful because there is light
bouncing off them. We see colorful light bouncing off of objects and interpret that as the object actually
physically being that color. However, if you saw the same object in the dark as you did in light, it would
be a different color. It would not just look like a different color, it would actually be a different color
because the color of an object is dependent entirely upon light. This is why it is so fascinating to learn
about. To break it down, there are three different things that happen when light waves hit an object.
Light waves are absorbed, reflected or transmitted. What one of those will happen is completely
dependent on an object’s molecular make up.
Generally defined, absorption, when talking in relation to light, is when light waves hit an
object and the object quite literally absorbs it. The light wave stops when it hits the object and the
energy that it has is turned into heat. Objects that absorb light are usually darker in color. Here is a more
precise way of defining and explaining absorption. Everything is made out of atoms and molecules,
which have electrons, and electrons vibrate at specific frequencies, called natural frequencies. If a light
wave hits an object with the same natural frequency as itself, the light wave gets turned into vibrational
motion. This light wave never comes back out, at least not in the form of light. It comes out in the form
of heat. In other words, when a light wave hits an object with the same natural frequency, the light is
absorbed into the object, creates motion in the electrons, and subsequently creates heat.
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The reflection of light waves occurs when the frequency of the light wave and the natural
frequency of the object are not the same. When a light wave hits an object that does not have the same
frequency as itself, the electrons in the object will still start to move. These electrons will move in small
sporadic ways however, not as a whole, which happens when the same frequencies are united. If the
light waves are being reflected, then the object will be opaque. This is because when light waves are
being reflected, atoms on the surface of the object will vibrate for small periods of time passing the
energy around the top layer and then reemitting the energy as a light wave on the same side it came
from. These light waves never make it past the surface of an object. The way that the light is reflected
depends on the surface of the object it is hitting. If the object is smooth, such as glass is, then the light
bounces off at equal angles to when it hit the object. If the object is rough, such as the earth is, then light
waves bounce off at many angles because of the uneven surface. When this happens, light is “scattered”.
What makes the difference between reflection and absorption are the atoms in the objects that the
light is hitting. Reflection, as I have just said, happens when the natural frequency of the light wave isn’t
the same as the natural frequency of the electrons in the object the light is hitting. While Absorption is
when the natural frequencies align, allowing the energy of the light waves to be absorbed into the object,
exciting the electrons even further and heating it up.
Transmission of light is when light waves enter one side of an object and come out the
other side in the form of light waves. Refraction is what happens while the light waves are actually
going through the object. Transmission of light waves occurs for the same reason reflection of light
waves occurs, because the frequencies of the light waves don’t match the frequencies of the electrons in
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the object they are hitting. The same as when light waves are reflected when they are transmitted,
objects’ electrons vibrate only for brief periods of time; different however from reflected light waves is
that this energy makes it through the object. Once the energy has made its way to the other side of the
object, it is reemitted as a light wave. Objects that transmit light are generally transparent because the
light goes through them. When transmitted light waves hit an object and start moving their way through
the object, they slow down significantly. When they slow down, the angle at which they are traveling
changes. This change in angle is called refraction.
Now that the basics of how light is reflected and absorbed into objects is covered, let’s talk about
the light itself. It is the absorbing and reflecting that shows us the color of an object, but it is light that
gives us color. White light is not white. It may look white but in actuality white light has the entire
spectrum of colors in it. We see the color on objects because we are able to see the color of the light that
is reflected. When white light hits an object, whatever colors whose light wave frequencies match that of
the frequencies of the object will be absorbed, the rest will be reflected or transmitted. If only one color
is reflected, then the object will be a solid color, say red. However if two colors are reflected, say red
and yellow, then the color that our eyes will see is orange. An object is really the color that it is not,
meaning it is the only color that it cannot absorb. All the colors that we don’t see are being absorbed by
the object and turning into heat. Black is created when an object absorbs all the colors, and that is why it
heats up a lot more on a hot and sunny day than white, which reflects all colors.
Pigment color is different than color from light because pigment is just like an object. Pigment
absorbs colors from white light and reflects selected ones that it has been made to reflect. This is why,
unlike light, when you mix all the colors of pigment together it makes black or dark brown. Each color
of pigment absorbs specific colors of the spectrum and reflects specific colors. If you mix all the colors
together, then the pigment absorbs all the colors, just like black.
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Color fascinates me. What if when you asked people what color something was, they would say,
“Well, it is a reflection of blank and blank light waves but an absorption of blank, blank and blank light
waves.” It would be a lengthy response, but it would still make sense because color is light. Which
makes be wonder, what color would everything be if there were no lights, but we could still see it. I
know it isn’t possible to see anything without light, but I am curious if everything would simply be
white because it would be the total absence of color. However, you still need light to make white. That is
a question that follows me everywhere. In short, color is amazing and light is spectacular because it
allows us to see color. I would recommend this as a topic for a rainy day. Color is the perfect thing to be
sucked into your computer reading about. It is incredibly fascinating, as well as useful, and intriguing
knowledge to posses. We have wireless Internet for a reason; I like to think that reason is to learn. Take
advantage of all the endless information on the Internet and educate yourself on something that you find
fascinating.
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Works Cited
"Absorption / Transmission / Reflection Spectroscopy." Andor. Oxford Instruments The
Business of Science, n.d. Web. <http://www.andor.com/learningacademy/absorption-transmission-reflection-spectroscopy-an-introduction-toabsorption-transmission-reflection-spectroscopy>.
"Absorption, Reflection, and Refraction of Light." Maya User's Guide. N.p., n.d. Web.
02 June 2015.
<http://download.autodesk.com/global/docs/maya2014/en_us/index.html?url=fil
es/BoL_Absorption_reflection_and_refraction_of_light.htm.topicNumber>.
"Bill Nye The Science Guy & Light and Color & Full Episode." YouTube. YouTube, n.d.
Web. 22 May 2015. <https://www.youtube.com/watch?v=MQJyLy62KRo>.
"Light Absorption, Reflection, and Transmission." Physics Classroom. The Physics
Classroom, n.d. Web. 21 May 2015.
<http://www.physicsclassroom.com/class/light/Lesson-2/Light-Absorption,Reflection,-and-Transmission>.
"Reflection, Transmission, and Absorption." Light Measurement. Gigahertz-Optik, Inc.,
n.d. Web. 20 May 2015. <http://light-measurement.com/reflection-absorption/>.
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