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### What is Optics?

You rely on optics everyday. Your digital camera, wireless mouse, and even your blu-ray disc of your favorite movie are all technologies enabled by the science of optics.

Optics is the science of light. More specifically, optics is a branch of physics describing how light behaves and interacts with matter. OK, that sounds like something your 5th period teacher rambles on about – right?

Think of it this way…The power and special properties of light can be used to explore the universe, monitor the environment, and even solve crimes. By utilizing their knowledge of how light behaves under different conditions, scientists and engineers create wicked cool technologies that make your world better.

Still out of the know? Start your exploration of the science of light by checking out some of the links below, play with the java applets, watch a movie or just stare at the colorful pictures – you are guaranteed to find something that will make you go hmmmm.

 Color General Magnification Medical Applications Optical Illusions Polarization Reflection Refraction Scattering Shadows Vision

## Color

Color Separation - The printing industry relies on a four-color separation process using cyan, magenta, yellow, and black dyes to faithfully reproduce artwork and photographs. This tutorial explores how these separations can be used to reconstitute a photograph.

Light and Color - Red, green, and blue are the primary colors used in the additive color system. When mixed in equal proportions (added together), the three primary colors yield white light. When mixed together in different proportions, you can make just about any color!

## General

Fermat’s Principle - Rays are traced through an optical system using Fermat’s Principle, which says that the rays of EM Rad follow only the fastest route when they travel from one point (A) to another (B).

Geometrical Optics - Geometrical optics, or ray optics, is frequently used to study how images form in optical systems.

Lenses and Mirrors - A lens is a transparent device with two curved surfaces, usually made of glass or plastic, that uses refraction to form an image of an object.

Optics is both science and engineering - Optics involves both science and engineering. Optics is a field of such variety that scientists and engineers with all kinds of interests contribute to it. Optics is a vibrant and growing field with a rich history.

Powers of Ten - Soar through space starting at 10 million light years away from the Milky Way down through to a single proton in Florida in decreasing powers of ten (orders of magnitude). Explore the use of exponential notation to understand and compare the size of things in our world and the universe.

## Magnification

Intel Play QX3 Computer Microscope Simulator - Explore how the new Intel QX3 Computer Microscope works to produce digital microscopic images.

Magnifying with a Bi-Convex Lens - Explore how a simple thin bi-convex lens operates to magnify a real image. This tutorial allows the student to move the lens with respect to the object being imaged and to discover how the proximity of the lens and object affect the real image.

Microscope Magnification - Explore what various things look like through a microscope at different magnifications. Samples include a computer chip, Moon rock, superconductors, the surface of a compact disc and several others.

Simple Magnification - Explore how a simple magnifying glass works with this tutorial designed to explain the concept of magnification. The visitor can use the mouse cursor to move a magnifying glass to change the image enlargement of an object.

Translational Microscopy - This interactive Java tutorial simulates the scanning of a sample under the microscope at a fixed magnification. Students must first focus the sample (as is the case with a real microscope), then they are able move the sample in all directions to thoroughly explore the various features exhibited by the sample. Brightness (Intensity) and Zoom controls allow fine-tuning of the microscopic images.

## Medical Applications

Optical Diagnosis - Using Optics to discover the mysteries of the body.

Optics in Surgery - Laser/Tissue interaction (or the application of lasers in therapeutic and surgical procedures with human tissue) has become more common in recent years.

## Optical Illusions

MoirĂ© Images - Watch how images are made to change both shape and size as a grid moves over them.

Optical Illusions - Optical illusions can change the way you perceive how events occur. Explore several different types of illusions using spinning disks, color wheels, and a MoirĂ© Pattern Generator.

Thaumatropes - Originally engineered as a spinning disk, we have applied Java to these optical illusions that allow the eye to merge two images so they appear as one.

## Polarization

Birefringent Crystals in Polarized Light - Examine a single crystal on a rotating stage with a virtual polarizing microscope. As the image is rotated through 360 degrees, it alternately becomes light and dark (twinkling) as its position with respect to the polarizer and analyzer changes. Visitors can also insert a virtual full-wave retardation plate into the light path to determine the sign of birefringence for the crystal.

Polarization of Light - This tutorial allows visitors to interactively block or pass light waves by controlling the alignment of polarizers with an incident light beam.

Polarized Light Microscopy - Explore how various crystallized specimens appear when viewed through a polarized light microscope. Samples include a Moon rock, a dinosaur bone, spinach and many others.

## Reflection

Angles of Reflection - Explore how light is reflected from a smooth surface using this interactive tutorial to modulate the angle of incident and reflected light.

How Do Chameleons Change Color? - A chameleon’s skin can quickly and dramatically change color, its eyes allow it to look in almost all directions without moving its head, and it even has a rudimentary third eye!

Multiple Images - Mirrors can be used to produce multiple images. This tutorial explores how two mirrors can be used to produce up to 17 images of a single object.

## Refraction

Aberrations - Aberrations are errors in an image that occur because of imperfections in the optical system. Another way of saying this is that aberrations result when the optical system misdirects some of the object’s rays.

Dispersion - If you’ve ever seen a rainbow or a prism split what appears to be white light into its rainbow of color components, you’ve seen dispersion.

Double Refraction - This tutorial explores birefringence or double refraction of light when passed through a crystal of Iceland spar. Students can move the crystal over an image of a ball-point pen and some printed text to explore how birefringence affects the refraction of light.

Newton's Prism Experiments - This tutorial replicates Isaac Newton's experiments with prisms through which he discovered that white light is made up of all the colors of the visible spectrum.

Optical Light Bench - Examine how an optical light bench can be used to observe what happens to light passing through a lens.

Refraction of Light - An interactive Java tutorial designed to demonstrate how a single wavelength of light is refracted by various media. The student can change the composition of the media, as well as the angle and wavelength of the incident light.

Snell’s Law, Reflection and Refraction - In order to follow the quickest path through a system, a ray changes direction as it travels from a medium of one refractive index to another medium that has a different refractive index.

What is a rainbow? - When sunlight encounters a drop of water in the atmosphere it can produce a colorful rainbow because the amount that light rays are bent as they pass in and out of the raindrop depends on the wavelength (or color) of the light.

Why do the Stars Twinkle? - Stars are actually very large, but they are very far away so they look small. In fact, stars are so far away from Earth that we commonly refer to them as being infinitely far away, which results in their looking like a point source of light.

## Scattering

Why is the sky blue, and the sunset red? - Take a look at light through a prism and notice all the different colors that you can see. Light that looks white to our eyes is actually made up of many different colors.

Eclipse of the Moon - Control the motion of the Moon as it moves into the shadow of the Earth.

Measuring With Shadows - Explore using shadows to measure relative heights by comparing the height of a Tyrannosaurus Rex shadow to that of a measuring stick.

Solar Eclipse - Control the motion of the Moon as it passes between the Sun and the Earth.