Driving question:

• What causes the color of a rainbow to appear when you look at the light bulb through a pair of rainbow glasses?

Materials:

• Rainbow Glasses
• Laser
• Light source

Procedure:

• Put on the rainbow glasses and look at a light. When this happens a rainbow will appear.

Safety:

• Do not look directly at sun or laser beams as they can cause permanent damage to your eyes.

Scientific Principle/ Essential Understanding: When looking through these glasses, you are looking through what is called "Diffraction Grating". Diffraction Grating is pieces of plastic that contain slit-like openings that are very narrow and closely spaced. When lights hits these openings, it bends the amount depending on the type of light.

• Observation: Each one of the glasses made a different shape.

• Analysis and Discussion: Rainbow glasses are very entertaining and a very interesting topic to learn about. W

• Conclusion: The diffraction of each glass made them have a different shape.

• Real Life Connections/ Further Applications:

1. Where and how is it currently being used?
2. How does it benefit our society?
3. What are some future benefits and application of this project?

Investigation:

• What is Huygens Principle and how can it be used to explain why interference and diffraction occurs in waves when they pass through small slits?

Huygens Principle states that every point on a wavefront is a source of wavelets, which spread forward at the same speed. Meaning every wavefront generates wavelets for the next wavefront. Kind of like a kid standing in the middle of the water, how ripples are created, those are called crests and troughs. The same thing happens when light is diffracted through a hole in a barrier, the wave lengths of the light form into a wavefront at the hole, where the wavelets are created, all at the same speed, produce light through the hole. Some angles of the light will be brighter than others because when the wavelets create crests that overlap each other, they will line up in a perfect line producing a light brighter if looked at, at this angle.

• If a transmissive diffraction grating is simply a piece of transparent medium with many small, closely-spaced dark lines on it, how does it produce an interference and diffraction pattern?

Since there are the microscopic dark lines inscribed onto the medium, the light passes through and the wavelets are created. When they intersect they form a pattern

• What causes the bright and dark areas in the laser's interference and diffraction pattern?

The pattern forms a square around the dot, a total of 9 dots will be seen. This is happening because the Rainbow Glasses' lenses are made of plastic sheet that have a microscopic grid inscribed into them. When light passes through this tiny grid, the light is diffracted. The diffracted light will create interference patterns. This creates four different pairs of spectra. One vertical spectra, one horizontal spectra and two diagonal spectra.

• Describe the interference and diffraction pattern of a ray of white light after it passes through a diffraction grating. Why doesn't the interference and diffraction pattern of the white light show as many bright and dark areas as the laser's interference and diffraction pattern? What does it show in place of the bright and dark spots?

When a white light is shown through a diffraction grating, colors from blue to violet can be seen near the white light source. But colors like red, orange and even green can be seen farther away from the white light source