REFRACT

Animation of Refraction of Light

Flash 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.

Some parameters (n₁, n₂, theta₁, theta₂) may be changed by the user. Click on the name of the parameter. The background of that name should turn red. Then enter a number (including a decimal point if desired) at the keyboard followed by pressing the enter key. When the number is completely entered, the new value of the parameter will appear on the screen unless it is invalid. Indices of refraction must be between 1 and 2.5 (including 1 and 2.5). Angles must be between 0 and 90 (not including 0 and 90).

The program recognizes the following commands.

stop Stop animation. Press stop again to resume animation.
reflection Remove the reflected wave. Press reflection again to restore the reflected wave.
frequency 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 frequency again to remove the detectors.
velocity 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 velocity 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 velocity again to resume animation.
sweep Sweep the angle of incidence from 0 to 89 degrees. Press sweep again to stop the sweep.
reverse Reverse the direction of wave propagation.
n₁= Change the value of n₁.
n₂= Change the value of n₂.
theta₁= Change the value of the angle of incidence if the incident wave is coming from the top half of the screen.
theta₂= Change the value of the angle of incidence if the incident wave is coming from the bottom half of the screen.

stop	Stop animation. Press stop again to resume animation.
reflection	Remove the reflected wave. Press reflection again to restore the reflected wave.
frequency	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 frequency again to remove the detectors.
velocity	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 velocity 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 velocity again to resume animation.
sweep	Sweep the angle of incidence from 0 to 89 degrees. Press sweep again to stop the sweep.
reverse	Reverse the direction of wave propagation.
n₁=	Change the value of n₁.
n₂=	Change the value of n₂.
theta₁=	Change the value of the angle of incidence if the incident wave is coming from the top half of the screen.
theta₂=	Change the value of the angle of incidence if the incident wave is coming from the bottom half of the screen.