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Exploring the Spectrum of Visible Light

 Spectrum of Visible Light

What is the Visible Light Spectrum?

The electromagnetic spectrum can be considered in terms of seven types of electromagnetic radiation, all corresponding to different wavelengths and frequencies: radio, microwave, infrared, visible light, ultraviolet, x-rays, and gamma rays. The visible light spectrum is the section of the electromagnetic spectrum which is visible to the human eye. The light in this section have wavelengths ranging from 380 nm and 760 nm.

Visible Light Spectrum

The visible light spectrum is often depicted as a scale of colors with different wavelengths. Sunlight, which is our primary source of visible light, and which is often referred to as white light, is actually the presence of all colors. Visible light travels at a speed of 300,000 km per second and can be broken down into seven colors. From longest to shortest wavelength, they are: red, orange, yellow, green, blue, indigo, and violet. To be clear, color is the eye’s perception of different wavelengths of electromagnetic light. Light, itself, does not possess color.

Properties of the Spectrum of Visible Light

Like any other form of electromagnetic radiation, visible light is subject to reflection, refraction, and diffraction.

  • Reflection is the process by which a light wave comes into contact with a surface and is thrown back towards its source.
  • Refraction is the change in direction a wave as a result of traveling from one medium to another.
  • Diffraction is the process by which a wave spreads out as a result of passing through a narrow opening.

Light, Energy, and Color Temperature of Visible Light

The color of a light is determined by the energy being radiated by the light’s source. The wavelength of the energy being radiated determines the color we perceive the source to be. Imagine a perfect black body, which absorbs and radiates all the energy that reaches it. The hotter the black body gets, the greater the energy it radiates and the shorter the wavelength of that radiation. Our eyes interpret this light as the colors associated with shorter wavelengths, such as blue and violet.

Temperature of Visible Light

Conversely, energy radiations with longer wavelengths are interpreted as the colors closer to red and orange. Incandescence is the phenomena when a body gets so hot that it begins to glow. The range of colors the eyes interprets from electromagnetic radiation of different wavelengths is commonly used to depict the visible light spectrum.

Experiments for Exploring the Visible Light Spectrum

There are lots of interesting and easy ways for you to explore the visible light spectrum. A great place to start is Newton’s prism experiment. With this experiment, Newton discovered that white light is a combination of all colors rather than a single color in itself.

Newton Prism Experiment

First, you’ll need a prism, a source of white light, and a white screen. On a flat surface, set up set up the prism and direct the white light through it. Position the white screen to receive the light as it exits the prism. On the white screen, you should see a rainbow. As we know, each color of the visible spectrum has a different wavelength and, therefore, is bent to a different degree as it passes through the prism. This property of light is what allows us to see the individual colors when the light exits the prism.

You can take this experiment a bit further. If you place a lens right in front of the screen and slowly move the screen away from the lens, the colors will combine back to a single white light. At this point, if you keep moving the screen away from the lens, the white light will separate back into the different colors but in the reverse order. If you move the screen back toward the lens, the colors will recombine to white, and then separate back into the constituent colors.

Optical Spectrometer

Another fun way to explore the visible light spectrum would be to make a simple spectrometer. An optical spectrometer is a scientific device used to split light into an array of its constituent colors. For this, you’ll need an old CD, a cereal box, a pair of scissors, aluminum foil, a 60 degree angle template, and tape.

  1. On the top of the box, use a straight edge to measure and mark off 1.5 inches along its length.
  2. Using the same straight edge, draw a guideline across the width of the box. Cut along the guideline, then unfold and cut off the flaps.
  3. From the corner of the box where the flaps were cut, draw a 3 inch line towards the center of the box on both sides.
  4. Using those lines as guides, cut two 3 inch slits on both sides of the cereal box.
  5. Insert the CD between the slits.
  6. Cut a rectangle on the opposite side of the box from where the CD was inserted. This rectangle should be half an inch from the top of the box, one inch high, and span the width of that side of the box.
  7. Cut enough aluminum for to cover the rectangle, then fold it in half. Align the crease with the center of the rectangular hole from the top and tape the other edge to the box.
  8. Cut another similar pieces of aluminum, fold and tape it from the bottom of the rectangle, leaving a 1mm slit between the two pieces of aluminum.
  9. Finally, tape the top of the box closed.
  10. Point the slit at any light source and look through the square hole. You should be able to see the rainbow colors.

Visible Light Spectrum and the Ecosystem

The visible light spectrum is a crucial part of the earth’s natural processes. The earth’s food chain depends heavily on it. Plants rely on visible light to power photosynthesis, the process by which they make food. Photosynthesis also produces oxygen and releases it to the atmosphere, making it available for human beings and other animals to breathe. Studies have also shown inadequate exposure to visible light causes brain damage and emotional illness in human beings.

Conversely, excessive exposure to the visible light can damage one’s eyes and skin. So, enjoy the wonders of visible light but, do so safely and responsibly.

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Need more ideas or equipment for creating an extraordinary light and color experience? Explore the collection of rainbow suncatchers, diffraction grating slides and diffraction glasses at Rainbow Symphony! Contact us today for any information on our products and services.

Diffraction Gratings: An Essential Tool in Modern Spectrometry

Diffraction is the bending of a wave as it passes around a corner or through an opening. The phenomena can be best observed using the prism experiment or Young’s Double-Slit Experiment. In the prism experiment, white light is passed through a prism and viewed on a white screen as it exits the prism.

On the white screen, you will observe an array of colors as each wavelength in the visible spectrum is bent to a different degree, effectively separating the white light into its constituent colors. Young’s Double Slit experiment demonstrates the same principle by passing light through a small slit and observing the light on a screen when it exits on the other side.

The discovery of light diffraction was monumental in optical physics because it proved light’s wave-particle duality. That is, it proved that light exhibits properties of both waves and particles. In this blog, we cover the applications of diffraction gratings for spectrometry tools in modern technology.

What is a Diffraction Grating?

Evolved from Young’s Double Slit experiment, diffraction gratings are the preferred method of light scattering in many spectrometers. A diffraction grating is a device that splits electromagnetic radiation into its constituent wavelengths. In a nutshell, a diffraction grating comprises slits of varying widths to match the wavelengths of the different colors of the visible spectrum. When white light is incident on the grating, its constituent colors are separate as they bend through the slit that matches their respective wavelengths.

While they are fairly simple devices, diffraction gratings for spectrometry tools have established a foothold in modern spectrometry and shaped the technology of our lives.

Spectrometry

The discovery of diffraction launched the scientific field of spectroscopy, the study of the interaction of matter and electromagnetic radiation. Since then, diffraction gratings have contributed significantly to modern science and are incorporated in many common spectrometry tools, including spectrophotometers and monochromators. They are generally prefered over prisms because they do not absorb UV or infrared radiation.

Types of Diffraction Gratings and Their Associated Spectrometry Tools

In general, there are four types of diffraction gratings: ruled gratings, holographic gratings, transmission gratings, and reflection gratings.

Ruled Gratings

Ruled gratings are created by physically etching several parallel grooves onto a reflective surface. Applications that require a narrow wavelength, such as spectrometers and monochromators, often benefit from having a ruled grating blazed at that specific wavelength. Commons applications for ruled gratings are:

  • Fluorescence Excitation
  • Telecommunications
  • Analytical Chemistry
  • Life Sciences
  • Physics
  • Space Sciences
  • Education

Note: The wavelength of electromagnetic radiation that yields the greatest absolute efficiency of the ruled diffraction grating is referred to as the blaze wavelength.

Holographic Gratings

Holographic gratings are developed by using a photolithographic process to generate an interference pattern between two UV beams, creating a sinusoidal index of refraction variation in a piece of optical glass. Generally, ruled diffraction gratings are lighter and cheaper than holographic gratings but they exhibit more stray light. On the other hand, holographic diffraction gratings are better for stray light performance but tend to have lower efficiency.

Transmission Gratings

One popular style of grating is the transmission grating. This type of grating is created by scratching or etching a transparent substrate with a repetitive, parallel structure. In a transmission diffraction grating, light passes through the material on which the grating is etched.

Transmission gratings are particularly useful in fixed grating applications such as spectrographs.

Transmission gratings have relatively low polarization sensitivity when compared to reflection gratings because incident light is not reflected by a mirror coating. Transmission gratings are particularly effective in compact, in-line configurations because light is transmitted through the grating. Transmission gratings are great in monochromators and spectrometers.

Reflection Gratings

A reflective grating is traditionally made by depositing a metallic coating on an optic and ruling parallel grooves in the surface. Reflective gratings are also commonly made by replicating a master diffraction grating version with epoxy and/or plastic. In all cases, light is reflected off of the ruled surface at different angles corresponding to different orders and wavelengths.

As evident in their descriptions, the four types of diffraction gratings listed are not necessarily mutually exclusive, and diffraction gratings are capable of incorporating components of multiple different types.

Diffraction Gratings for Spectrometry

Diffraction gratings are commonly used in monochromators, spectrometers, lasers, wavelength division multiplexing devices, optical pulse compression devices, and many other optical instruments. CDs and DVDs are good, easily observable examples of diffraction gratings. Reflecting sunlight off a CD or DVD onto a white wall will yield light of different colors i.e, different wavelengths of the visible spectrum.

Spectrometers

Perhaps the most elementary application of diffraction gratings for spectrometry tools, spectrometers are used to separate white light into its constituent wavelengths.

Monochromators

In some ways, monochromators are kind of the reverse of spectrometers. While spectrometers separate white light into all its constituent colors, monochromators are devices used to filter out all but a narrow band of electromagnetic energy. This particular application of diffraction gratings for spectrometry tools is very useful when tunable monochromatic light is needed.

Lasers

Diffraction gratings are often used in lasers for wavelength tuning. That is, calibrating the laser to emit a specific wavelength of electromagnetic radiation.

Optical Communications

Holographic diffraction gratings have widespread use in optical communications and industrial measurement across near infrared spectral regions in which high performance and environment resistance are necessary.

Pulse Compression

Diffraction gratings have also found a foothold in the pulse compression technology. The gratings used for these applications tend to be made of high-purity monolithic fused silica, which is ideal for certain laser wavelengths. This application of diffraction gratings for spectrometry tools is generally found in laser material processing, the semiconductor industry and in the medical industry for refractive cornea correction.

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Rainbow Symphony is proud to provide the educational tools you need to optimize your optical experiences, including diffraction gratings for spectrometry. For more information on our products and spectrometry tools, check out our entire online store. Our dedicated team of professionals is here to provide expert knowledge and an outstanding shopping experience, so don’t hesitate to contact us today!

How to Create a Double Rainbow

Double Rainbow

From decorating your home to teaching a room full of students, Rainbow Symphony loves bringing rainbows and science into your daily life! We’re experts on rainbows, as well as all things, light and color so when you’re wondering how to create a double rainbow, we can help! If you’re ready to learn what a double rainbow is, how to make one that’s vibrant all the time, and where you can see them in nature, read on here for more information.

What is a Double Rainbow?

You may have thought there was only one kind of rainbow! In fact, there are actually 12 classifications of rainbow that are determined by which colors are visible in the arc. When it comes to double rainbows, these classifications still exist, but the way the rainbow itself is created is a bit different from a single arc rainbow.

A double rainbow is when two distinct arcs are formed. They have separate origin points and the second arc is a mirror image of the first with the colors reversed. The indigo hue will be on the outside, while the red shades will be on the inside of the arc! The second rainbow also tends to be slightly lighter and much larger than the original rainbow arc. There is always some distance between the two bands, and the space in between is called Alexander’s band.

How Are Double Rainbows Created?

A single arc rainbow is created when sunlight enters a raindrop, is refracted (broken up) into multiple colors, and reflected off the back of the drop and out again. What we end up seeing is a single rainbow arc made up of multiple colors.

In a double rainbow, the light is reflected back twice within the same drop. Instead of creating a triangular line of reflection in the raindrop, the light bounce off once more to make a square shape. The second rainbow generally appears about 10 degrees above the first rainbow. It’s not unusual to experience triple or even quadruple rainbows when the conditions are just right!

Where to See Rainbows in the Real World

You don’t have to know how to create a double rainbow to see them in the real world. Rainbows generally appear after a rain shower or thunderstorm, but you can also see them anywhere water and light mix. Next time you’re walking by some sprinklers or there’s a fine mist in the air, look around you to spot some colorful displays. If you’re looking for the perfect double rainbow, the best conditions to view them are at dusk after a heavy rain.

How to Create Your Own Double Rainbow with a Jar of Water

Your Own Double Rainbow with a Jar of Water

If you’re ready to learn how to create a double rainbow yourself, you’ll need to gather a few tools.

Materials:

  • A Bright Light Source
  • A Clear Jar Full Of Water
  • A Dark Room

Your bright light source acts as the sun, your jar of water is the raindrop, and the dark room is the perfect canvas on which to paint your rainbow. It can be a little tricky to spot the rainbows on your first try, but keep at it and soon you’ll learn how to create a double rainbow easily.

Instructions:

Since rainbows are usually seen after rainstorms, when the light is behind you, you’ll need to set up your lamp or light bulb on a desk or table behind where you plan on placing your jar of water. Set your light as high as possible and sit below it with the jar of water. Hold the jar directly in front of you and slowly raise it above your head until you see a reflected spot inside it that looks like a rainbow. Keep raising the jar slowly until you see a second rainbow spot.

This experiment is perfect for kids of all ages and can really help a teacher illustrate how rainbows work!

How to Create a Double Rainbow with a Prism

Create a Double Rainbow with a Prism

For rainbows that last a little longer and don’t require you to stay still holding up a jar of water, try this experiment instead.

Materials:

  • Glass Prism
  • Strong Sunlight
  • White Cardboard or Paper

Instructions:

Place the cardboard or paper in a space with lots of sunlight. Put the prism on the paper or in a place above it in the sunlight. Rotate and shift the prism around until you see rainbows projected on the paper! You don’t always need to use paper if the walls and floor in your room are already light colored.

How to Create More Double Rainbows with Rainbow Symphony

 Rainbow Symphony

Rainbow Symphony loves bringing you rainbows so much, that we’ve made it super simple to decorate your space with them. Our suncatchers are actually made with a built in holographic prism that allows you to place them anywhere with strong sunlight to get rainbows bouncing everywhere anytime the sun is out!

Now that you know what a double rainbow is and how to create your own double rainbows, we want you to start experimenting! Want more details on twinned rainbows, what kinds of rainbows exist in space, and what a double rainbow is? Check out our Rainbow Infographic today to learn about the different kinds of rainbows!

How Do 3D Glasses Actually Work

3D Glasses Actually Work

While most people think that 3D movies are an invention of the last 40 or 50 years, it may surprise you to know that the first 3D movie came out in 1922. Since then, 3D technology has been in and out of the mainstream every few years. The biggest advance in 3D popularity was brought about due to James Cameron’s Avatar film. With the explosion of popularity in the 21st century, it looks like 3D technology is here to stay, with nearly every movie available to view in both digital and 3D in most theaters.

You may have seen a 3D in theaters and even watched 3D on your television at home, but do you know how 3D glasses work? There are a few different types of 3D glasses that work in tandem with projection to present you with an amazing visual display. Read on here to learn more from your friends at Rainbow Symphony!

How Do 3D Glasses Work

There are generally three types of 3D glasses including anaglyph, polarized, and shutter. Each uses different methods to bring flat images on your screen to life.

How Do Anaglyph 3D Glasses Work?

Anaglyph 3D Glasses Work

These are the most common types of 3D glasses and the iconic image many think about when they wonder how 3D glasses work. These glasses utilize special red / cyan lenses to interpret the image. These lenses produce the images you see by color filtering the layered image that you’re actually looking at. While one lens filters out all the red in an image, the other lense filters out the cyan, causing your brain to see the picture in 3D. The image you’re looking at is usually the same image projected from two different angles — or two entirely different superimposed images.

Anaglyph glasses come in several variations on the red / blue lens including:

How Do Polarized 3D Glasses Work?

Polarized 3D Glasses Work

How 3D glasses work when it comes to polarized lenses depends on deceiving your eyes just like anaglyph glasses do. How do polarized 3D glasses work, you ask? They restrict the light that enters your eyes, but instead of restricting the light by red and blue colors, they have a yellowish brown tint.

The image on the screen also has a role to play. In addition to the polarization on the glasses, the projected image is actually two images that are superimposed on the same screen through a orthogonal polarizing filter. Then the glasses, which have the same type of filter, allow each eye to see a the two individual images on the screen.

These glasses are actually the optimal choice for IMAX 3D movies and they’re the grey lens glasses you normally get at the theater today.

How Do Shutter 3D Glasses Work?

Shutter 3D Glasses Work

Shutter glasses are considered the most advanced type of 3D glasses available today. While the other two types of 3D glasses use something called passive 3D, shutter glasses utilize active 3D. They don’t use filtered image or color to create a three dimensional effect. Instead, shutter glasses work through LCD screen technology that darkens each lens, alternating the left and the right. The lens darkening happens so quickly that you don’t notice the effect unless you’re paying close attention.

Shutter glasses are usually battery powered, or even USB-supported, and are more expensive than traditional 3D glasses. The cost of these glasses make a huge difference to the image quality. You can get shutter glasses from Samsung, Panasonic, Sony, and more.

Why Do 3D Glasses Work?

3D Glasses Work

How 3D glasses work depends solely on how the eyes work and communicate with your brain. Human eyes have binocular vision that works best when you use both eyes simultaneously. Binocular vision gives you depth perception and allows you to tell which objects in your line of sight are closer or farther away.

Binocular vision relies on the distance between your eyes to present you with two different perspectives on the same thing. The distance between your eyes is generally about two inches apart, so the images each eye presents help to build a complete picture.

How Do 3D Glasses Work with Binocular Vision?

All types of 3D glasses work by making each eye see two different things. Whether it’s one eye seeing a red image and the other eye seeing a blue one or lenses that alternate darkening and lightening, your eyes seeing different things trick your brain into interpreting them in spectacular 3D.

3D Glasses at Rainbow Symphony

 Rainbow Symphony

Now that you know a little more about how 3D glasses work, we hope you’ll enjoy using them even more. Part of the reason we know so much about 3D glasses is because we design and manufacture so many different styles. From custom frames to a variety of colored lenses, Rainbow Symphony can offer you a massive selection of products. Whether you’re hosting a large event or you want to spend a night at home with friends and family watching 3D movies or playing video games, we can help.

Learn more about 3D glasses, rainbows, and solar phenomena when you stay up to date with our blog!

Different Kinds of Rainbows

Different Types Of Rainbows

Whether you stand outside during every rain shower to spot rainbows or you just enjoy seeing them around, there are tons of different kinds of rainbows to spot and learn about. From multiple variations on the single arc rainbow to twinned rainbows and double arcs, check out what rainbows hold in store for you!

Singe Arc Rainbows

There are 12 different kinds of single arc rainbows that are decided based on the colors, strength of the bands, and supernumerary bows that appear, or don’t appear, in the arc. Here are the basics:

  • RAB-1 has all the colors visible, strong Alexander band, and supernumerary bows.
  • RAB-2 has all the colors visible, strong Alexander band, but no supernumerary bows.
  • RAB-3 has all the colors visible, weak Alexander band, and supernumerary bows.
  • RAB-4 has all the colors visible, weak Alexander band, but no supernumerary bows.
  • RAB-5 has no violet or no blue color.
  • RAB-6 has no green color.
  • RAB-7 has no violet and no blue color.
  • RAB-8 has no blue and no green color.
  • RAB-9 has only blue and red colors.
  • RAB-10 has only yellow and orangey red colors.
  • RAB-11 has only red colors.
  • RAB-12 is an unspecified other kind of rainbow.

You can create many of these rainbow reflections with Rainbow Symphony products like the Gem Series.

Double Rainbows

The double rainbow is another different kind of rainbow that you may see on a regular basis. Sometimes light is reflected off the same raindrop more than once to create a double rainbow. These are two separate arcs that appear together. The second rainbow will be an inverted rainbow reflection of the first — with the red on the inside and the blue on the outside. It’s also often much lighter than the first rainbow. On very rare occasions, you may see triple and quadruple rainbows.

Twinned Rainbows

Twinned rainbows may look like double rainbows at first, but if you look closer, they actually meet at the base. These are two arcs that split from the same spot. Scientists have yet to discover what causes twinned rainbows to appear!

Rainbows In Space

While different kinds of rainbows may not appear in space itself, as there is nothing substantial enough to reflect light, they may appear on other planets and moons. One of Saturn’s moons, Titan, has moisture and an atmosphere that is friendly to rainbow creation. It is believed by scientists that Titan is one place outside of Earth that rainbows can appear!

Rainbow Symphony Favorites

Rainbow Symphony loves rainbows so much, we keep them around us all day long. From our window film to our suncatchers, decorating with rainbows is easy when you browse our collection!

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