Light & Color

One of the most common questions asked by students is “Why is the sky blue?” or “Why is the Sun yellow?” The answer is found by understanding color science concepts and some basics of color addition. Assuming that the Sun is “white” as viewed from space (no atmosphere) and that the three primary colors of light (red, blue and green in equal hues, saturation levels, etc) compose the white color that is observed.

You may not be aware of it, but polarized light is all around you. Do you have an LCD flat screen television, a laptop computer, a calculator, or other liquid crystal display? Well then, you have been exposed to polarized light. Light reflected from non-metallic surfaces such as water, a polished table top, and glass is also partially polarized as is the light scattered by the earth’s atmosphere.

Shadows are ubiquitous, but often go unnoticed. Shadows are important historically, for they provided early evidence that light travels in straight lines. Humans constantly, but unconsciously, use shadows to judge the shape of objects in their environment. Because shadows reveal much about an object’s extension in space, they are often used to heighten the illusion of depth in a painting.

The sky offers a wide variety of stunning optical effects. A source of inspiration for poets and songwriters alike, these atmospheric phenomena include red sunsets, rainbows, mirages, halos, glories, and coronas. These effects are the result of the interaction of light from the sun or moon with the gases in the atmosphere, clouds, ice crystals, smoke, dust and other airborne particulates. Some of these phenomena can be seen almost every day; others occur less frequently. In this issue of CoolStuff we will examine examples of atmospheric optical phenomena and how they may be demonstrated in the classroom.

Each new school year offers endless possibilities for igniting student interest in science. The principles students study in your classroom touch every aspect of their lives. Seeing the science involved in everything from a rainbow to a rock concert can be rewarding and enjoyable; having an understanding of the underlying physical principles behind these phenomena serves to heighten these experiences even more.

The constituent colors in a beam of light are revealed when the light is dispersed by a raindrop or passed through optical instruments known as prisms and diffraction gratings. In each case, an array of colors, or spectrum, is observed.Much of what we know about the makeup of matter has been gained through spectroscopy, the study of spectra.

We've decided it’s time to revisit the Haunted Laboratory in search of even more science tricks and treats.This edition of CoolStuff features some new exhibits designed to put a spooky spin on science. The displays, selected with ease of construction in mind, use materials and apparatus found in most science storerooms.

Although a school's science laboratory is the traditional arena for exploration and experimentation, other venues, such as interactive science centers, do exist. For some time now we have been taking advantage of yet another setting: the home. Using simple materials, our students are encouraged to do science experiments with family and friends. The benefits of at-home science activities are many. They increase the time students are thinking about and doing science. Since many of the explorations focus on counterintuitive phenomena, students delight in sharing unexpected outcomes with others. Needless to say, parents love seeing what their children are doing in school.

While doing science in the hallway or other non-traditional settings may seem a bit unorthodox, this form of informal education beckons members of the entire school community to learn just how interesting and enjoyable science can be.

As strange as it may seem, science and Halloween do have something in common: they both exemplify our innate fascination with the mysterious. The concept of a haunted science lab was conceived of over twenty years ago by Creighton University physics professor Tom Zepf. It began as a collection of activities in Light, Color and Lasers, a core-curriculum course he was teaching at Creighton. Gradually the annual Halloween event evolved into laboratory-based experience consisting of over three dozen displays demonstrating a wide range of physical principles, all of which invite interaction.