Introduction to Light: An Illuminating Day!
Students were very busy this week exploring the nature of LIGHT. Light is a form of energy that is a small part of the electromagnetic spectrum. Light travels in waves, and different types of light have characteristic wavelengths. We see different colors because each color of light has a different wavelength. You may remember the mnemonic “ROY G BIV”, which helps remind people the order of colors in the rainbow. We also call those colors of light visible light because they are the wavelengths that we can see. Other animals can see light outside of the range of visible light. Bees can see ultraviolet or UV light, while fish can see infared light!
The students modeled a light wave using a rope, and learned that short wavelength, high frequency, and high energy all go together. A series of activity stations helped reinforce their understanding of the law of reflection, how refraction and diffraction bend light waves, and why and how we perceive different colors. We examined the way light interacts with materials and the terms absorption and transmission were introduced, with examples of materials illustrating each property. The students were also very interested in our experiments dealing with the effects of reflection (the bouncing of light as it interacts with the surface of an object). A laser pointer was taped to a desktop, and the students were given small wooden blocks with mirrors affixed to one side. Their objective was to reflect the beam of the laser pointer off the mirrors so that it hit a taller block, the “target.” This activity reinforced understanding of the law of reflection: the angle of incidence is equal to the angle of reflection.
Visible light forms a small portion of the electromagentic spectrum. Electromagnetic energy travels in waves and spans a broad spectrum from very long radio waves to very short gamma rays. The human eye can only detect only a small portion of this spectrum called visible light. A radio detects a different portion of the spectrum, and an x-ray machine uses yet another portion. NASA’s scientific instruments use the full range of the electromagnetic spectrum to study the Earth, the solar system, and the universe beyond.
NASA’s Chandra X-ray Observatory explores the Universe in X-rays, a high-energy form of light. By studying X-ray data and comparing them with observations in other types of light, scientists can develop a better understanding of objects likes stars and galaxies that generate temperatures of millions of degrees and produce X-rays.
To recognize the International Year of Light, the Chandra X-ray Center is releasing a set of images that combine data from telescopes tuned to different wavelengths of light. You can find these spectacular images in the link below.