Thursday, January 29, 2009
How Light Travels, Microscope
In class today we were given an introduction on the properties of light, and also the basics of microscopy.
Q: When does light travel in straight lines?
A: When it doesn't!
There are a umber of reasons why light does not travel in a straight line. When light travels through a medium such as a prism, it can change directions. Additionally, a large gravitational force such as the sun can bend light.
Biophotnics 1/26/09
Geometric Optics is a field of optics that seeks to explain how light travels, generally as a particle. In class we discussed reflection, diffraction, refraction.
Diffraction is the bending of light as it passes around the edge of an object (1)
Refraction occurs as light travels from one medium to another changing its speed and direction. This can be seen by placing an object in water (2)
Reflection: When a wave approaches a reflecting surface, such as a mirror, the wave that strikes the surface is called the incident wave, and the one that bounces back is called the reflected wave (3)
When I searching on the interned about these three different properties of light I cam across the optical phenomenon Glory. In this phenomenon light is reflected, refracted and diffracted.
After learning about the different ways that light travels we got together with our groups and looked at different lenses. In this experiment we wanted to observe how light travels through certain lenses. When looking though one of the lenses the image appeared to be inverted. Videos of the experiment can be seen below:
Videos will be posted Shortly!
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In class we also we introduced to the parts of a microscope. We learned our to look at skin cells under the microscope.
Sources
(1) http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/opt/mch/diff.rxml
(2) http://www.ps.missouri.edu/rickspage/refract/refraction.html
(3) http://www.tpub.com/neets/tm/106-3.htm
Wednesday, January 21, 2009
First Day of Class
Two things that came to my mind when I thought about light were:
1) Photosynthesis
2) The concept of the Speed of Light
Other groups and group members came up with:
Travels as a particle
part of electromagnetic spectrum
Travels in a vacuum
We also described different light sources that we saw. The glow stick produced a light green color that was easy to look at, while some of the other light sources were extremely bright and strained the eyes (LED, Fluorescent Lamp). Also we shined the lights on different CD surfaces to see what type of spectrum appeared. Some videos and pictures of that experiment can be seen below.
Finally, I especially liked learning about the chemistry behind the Glow Stick. The source of the glow comes from a chemical reaction between H2O2, and a oxalate ester. Depending on which color is desired different dyes are added.
(No Laughing During Videos!)