REFRACT

Animation of Refraction of Light

OpenGL Version

This animation represents the refraction and reflection of light as it passes from one medium into another. When the animation begins, the incident and reflected waves are in a medium with index of refraction n1=1 (like air), and the refracted wave is in a medium with index of refraction n2=1.5 (like glass). On the right side of the screen are shown the values of the indices of refraction. On the left side of the screen are shown the angles of incidence and refraction.

The program recognizes the following commands. The command may be executed by either clicking the button with the mouse (first column below) or by pressing a key (second column below). The mouse buttons along the bottom of the screen may be removed from the screen by pressing the M key. Press M again to restore buttons.

pause S Stop animation. Press G to resume animation.
resume G Resume animation.
reflect R Remove the reflected wave. Press R again to restore the reflected wave.
frequency F Frequency demonstration. This demonstrates that the frequency of the waves is the same on both sides of the interface. Two "wave-front detectors" appear. The detectors flash yellow each time a wave front passes through it. You can see that the detectors are flashing at the same time and therefore with the same frequency. Press F again to remove the detectors.
velocity V Velocity demonstration. This demonstrates that the waves are traveling slower in the medium with the largest index of refraction. The animation stops and a red dot appears on top of a wavefront on each side of the interface. Press V again and the waves resume their motion. After a few moments, the animation stops again so that you can see how far each red dot has traveled. You will see that the wave in the medium with largest index of refraction has traveled the least distance and is therefore traveling the slowest. Press G to resume animation.
sweep W Sweep the angle of incidence from 0 to 89 degrees. Press W again to stop the sweep.
reverse I Reverse the direction of wave propagation.
n1= 1 Change the value of n1.
n2= 2 Change the value of n2.
deg A Change the value of the angle of incidence. Note that if the incident wave is above the interface, you must click on the button above the interface. If the incident wave is below the interface, you must click on the button below the interface.
quit Q Quit program.

DOS Version

The animation represents the refraction of light as it passes from air into glass.

The upper half of the screen (red) represents air. The lower half of the screen (blue) represents glass with an index of refraction equal to 1.5. The wave slows down as it enters the glass and therefore changes direction. You can see that the wavelength of the waves is shorter in the glass than in the air.

The program recognizes the following commands:

S Stop animation. Press G to resume animation.
V Velocity demonstration. This demonstrates that the waves are traveling slower in the glass than in the air. The animation stops and a single wave front on each side of the interface is highlighted with yellow. Press any key and the waves resume their motion. After a few moments, the animation stops again so that you can see how far each high-lighted wave has traveled. You will see that the wave in the air has traveled the farthest and is therefore traveling the fastest. Press any key to resume animation.
F Frequency demonstration. This demonstrates that the frequency of the waves is the same in both the air and the glass. A "wave-front detector" appears in the air and in the glass. The detectors flash yellow each time a wave front passes through it. You can see that the detectors are flashing at the same time and therefore with the same frequency. Press G to remove the detectors.
Q Quit program.
? Help. These commands are listed.

pause	S	Stop animation. Press G to resume animation.
resume	G	Resume animation.
reflect	R	Remove the reflected wave. Press R again to restore the reflected wave.
frequency	F	Frequency demonstration. This demonstrates that the frequency of the waves is the same on both sides of the interface. Two "wave-front detectors" appear. The detectors flash yellow each time a wave front passes through it. You can see that the detectors are flashing at the same time and therefore with the same frequency. Press F again to remove the detectors.
velocity	V	Velocity demonstration. This demonstrates that the waves are traveling slower in the medium with the largest index of refraction. The animation stops and a red dot appears on top of a wavefront on each side of the interface. Press V again and the waves resume their motion. After a few moments, the animation stops again so that you can see how far each red dot has traveled. You will see that the wave in the medium with largest index of refraction has traveled the least distance and is therefore traveling the slowest. Press G to resume animation.
sweep	W	Sweep the angle of incidence from 0 to 89 degrees. Press W again to stop the sweep.
reverse	I	Reverse the direction of wave propagation.
n1=	1	Change the value of n1.
n2=	2	Change the value of n2.
deg	A	Change the value of the angle of incidence. Note that if the incident wave is above the interface, you must click on the button above the interface. If the incident wave is below the interface, you must click on the button below the interface.
quit	Q	Quit program.