Prism Glasses (Double Axis) - Pack of 10

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(8 reviews)
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These highly efficient, double axis, holographic diffraction grating lenses separate light from any source into its spectral components for study and analysis. Lenses are mounted in sturdy cardboard frames. Sold in sets of 10.

Description

These highly efficient, double axis, holographic diffraction grating lenses separate light from any source into its spectral components for study and analysis. Lenses are mounted in sturdy cardboard frames. Sold in sets of 10.

Lesson Ideas

When we begin learning about light, we usually start by talking about the colors of the spectrum and the fact that white light can be broken up, or dispersed into a spectrum of colors. To disperse light into its spectrum, Sir Isaac Newton used a prism. However, in recent years the diffraction grating has replaced the prism for this purpose because it is easier, more effective, and less expensive.

Diffraction gratings are not new. They've been the basis of spectroscopic instruments for a long time, but these instruments are not necessary for many learning purposes. You can see the exciting and detailed spectra simply by holding a diffraction grating up to your eye and looking through it at a light source in a dark place.

Eventually, the question arises, 'How does a diffraction grating work?' It's not easy to find an answer to this question that doesn't get mathematical, yet explains the principal in a satisfying way. The following attempts to do that.

Waves in a Pond
Light waves are similar to water waves in many respects. Let's start with the familiar situation of water wave ripples due to a dropped pebble. Their spread (concentric circles) can be understood by considering each point along a wave, or wave front, to be the source of a new wavelet, each source having the same phase.

Now let's apply this to a wave that encounters an obstruction such as a narrow slit. The wave spreads out in a circular pattern. The difference between successive peaks or valleys is called the wavelength.

Now let's increase the number of narrow slits, equally spaced. This is called a diffraction grating.

When a light wave encounters a diffraction grating, the light spreads as if it originated from many point sources, each in phase with one another. Each wave spreads out in a circle, but now there are centers at each slit. If one wavelet's peak lies on another wavelet's valley, the result is neither peak nor valley, but rather cancellation. However, if one wavelet's peak lies on another wavelet's peak, they add constructively, making a wave twice as high.

There are special directions where cancellation is avoided and the wavelengths add constructively. The direction is different for different colors because different colors have different wavelengths. For example, since the wavelength of red light is longer than the wavelength of blue light, a red beam is diffracted or bent further than a blue beam when it passes through the diffraction grating.

This is how a diffraction grating breaks up the colors of white light. White light has many colors. Between red and blue are other colors, like orange, yellow, and green, whose wavelengths are intermediate between those of red and blue light.

Putting all this together, we can see how a beam of white light, which contains all the colors, gets diffracted or bent into a spectrum of colors.

Reviews

8 reviews
Prism Glasses
Mar 13, 2019
I find the prism glasses to be a great addition to my outreach program. I first have the audience look at a white microlight and ask what color do they see. I then have them put on the glasses and ask what color do they now see - the rainbow of colors. I talk about how Issac Newton, a very long time ago, passed white light through a prism and saw that white light was made up of all the visible colors (I even have a photo of this), explaining that these glasses were like a bunch of tiny prisms that separated the white light into its component colors. We then look at the various colored microlights. They see the predominate color but also see bits of other colors as well. I change to my lasers (red, green, and violet) and have them look at the spot on the wall using the glasses. (Never shine lasers directly at the audience or where reflections would reflect back to the audience.) They see multiple dots of the color but this time only that color. We talk about the difference between the microlights which "leak" other colors and the lasers do not leak; they are truly one color. Finally, I superimpose the green laser light onto the red and ask the audience to tell me what they see through the prism glasses - the green and red are separated from one another. This helps the audience to better understand how light can be separated into its component colors using the prism glasses. Really cool and a great teaching tool. Highly recommend them for all ages!
Kenneth Lyle

2   0

Great inexpensive demonstration
Jan 8, 2018
These are a great starter for the discussion of spectroscopy and elements, and for light refraction - plus, they are inexpensive enough to send home with the kids!
JHemel

0   0

These are great
Jun 11, 2015
The delivery was quick and the glasses are of great quality, thank you!
Echo Johnson

0   0

Feb 4, 2013
These are just what I wanted. They enhance all kinds of things and make the visual experience really fun and deeply thoughtful...
Neal Leatherman

0   0

Not as good as picture
Aug 28, 2012
Kind of nice but not as good as picture in catalog.
Allan

0   0

Fantastic
May 29, 2012
Light has always intrigued me.
Matthew

0   1

Mrs. Dennen
May 25, 2012
Diffraction grating film is always a hit!
Cheri Dennen

0   0

May 22, 2012
This is an excellent way to teach about the wavelenghts of different colors. Use the different colored light bulbs and discuss why students can still see other colors(the glass is painted, it is not really the wavelength. Also use a laser to show when all of the color wavelenghts are the same. And compare flourescent, incadescent, and halogen light bulbs to see the amount of each wavelength.
Linda Guillory

0   0

NGSS

This product will support your students' understanding of the Next Generation Science Standards (NGSS)*, as shown in the table below.

 Elementary Middle School High School 1-PS4-2 Students can conduct investigations showing evidence of illumination from an external source such as the Sun. 1-PS4-3 Students can use this tool to conduct an investigation of how different materials affect the path of a beam of light. MS-PS4-2 Students can use this tool to develop and use a model to describe how waves are reflected, absorbed, or transmitted through various materials. HS-PS4-1 Students can use lenses to conduct investigations and use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling in various media. HS-PS4-5 Students can use the Prism Glasses to conduct investigations about technological devices use the principles of wave behavior and wave interactions with matter to transmit.

Suggested Science Idea(s)

1-PS4-2
1-PS4-3
MS-PS4-2
HS-PS4-1
HS-PS4-5

Students can use this tool to develop and use a model to how waves are reflected, absorbed, or transmitted through various materials. These glasses are excellent for viewing visible light in rainbow form. Caution! Never look directly into the sun with these glasses.

* NGSS is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of, and do not endorse, this product.

Q & A