The Electromagnetic (EM) Spectrum Hawaiian Comparisons to the Sizes of Wavelengths: Aloha Tower Aloha Stadium Kamehameha Butterfly Hale (Hawaiian House) 10 10 3 Longer Point of a Needle -2 Plant Cell Bacteria 10 10 -5 Protein 10 -6 Water Molecule Atom 10 -8 10 -10 -12 Shorter Wavelength (Meters): Radio Waves: Microwaves: Radio waves have the longest wavelength in the EM spectrum. As implied, radio waves bring music to radios, but they also provide signals to cell phones, televisions, etc. Radio waves are received at an estimate of 100 MegaHertz or 100 million cycles per second by FM radios. In 1932, radio waves were discovered to be given off by astronomical objects. Since then, astronomers have been developing sophiscated systems to make visual images using the radio waves Infrared: Since microwaves can penetrate haze, light rain, snow, clouds and smoke, these waves are ideal for viewing the Earth from space. The wavelength of micro waves in a microwave oven is about 11 centimeters (4.3 inches). Visible: Infrared light has a range of wavelengths like visible light. “Near infrared” light is closest in wavelength to visible light and “far infrared” is closer to the microwave region of the electromagnetic spectrum. The longer, far infrared wavelengths are about the size of a pin head and the shorter, near infrared ones are the size of cells, or are microscopic. Far infrared waves are thermal (in the form of heat), while shorter infrared waves aren’t thermal, in fact, they can’t be felt. Regardless, many things, including humans, emit infrared light. Visible light waves are the only waves in spectrum that humans can see. These waves are seen in a range of colors with red having the longest wavelength and violet (purple) having the shortest wavelength. When all the waves are seen together, white light is created. Water vapor in the atmosphere breaks apart the wavelengths, which is why rainbows can be seen in the sky. The wavelength of visible light is a little bit less than a millionth of a metre. Ultraviolet: Ultraviolet light is invisible to the human eyes, but some insects, like bumblebees, have proven to be able to see ultraviolet light. The ultraviolet part of the spectrum is divided into three regions: the near ultraviolet, the far ultraviolet, and the extreme ultraviolet. The three regions are distinguished by how energetic the ultraviolet radiation is, and by the “wavelength” of the ultraviolet light, which is related to energy. Star, galaxies, and even the Earth can be studied by the ultraviolet light that is given off. The wavelength of ultraviolet light is less than 375 nanometres. X-Rays: As the wavelengths of the spectrum decrease, the energy increases, such as how x-rays tend to act more like a particle than a wave. Many things in space emit Xrays, among them are black holes, neutron stars, binary star systems, supernova remnants, stars, the Sun, and even some comets! Bones and teeth are dense and absorb more X-rays than your skin does due to containing a large amount of calcium. As such, silhouettes of your bones or teeth are left on the X-ray film while your skin appears transparent. Gamma Rays: Gamma rays have the smallest wavelength, but have the most energy out of all of the other waves in the spectrum. These waves are generated by radioactive atoms and in nuclear explosions. Gamma-rays can kill living cells, a fact which medicine uses to its advantage, using gamma-rays to kill cancerous cells. Unlike optical light and x-rays Gamma rays cannot be captured and reflected in mirrors. Possible Sources of these Wavelengths: Aircraft and Shipping Radios AM Radio FM Radio and TV Cell Phones Microwave Ovens Radar Humans Lightbulb UV Rays X-Rays Radioactive Elements Lower 10 Higher 5 Poster created by: Quinn Hamamoto Waiakea High School Hilo, Hawaii Grade 12 Summer ‘10 Huiana Intern 10 6 10 7 10 8 Find out more at: http://outreach.jach.hawaii.edu 10 9 10 10 10 11 10 12 10 13 10 14 For a hardcopy of this poster please contact [email protected] 10 15 10 16 10 17 10 The Fine Print: Background copyrighted by SoundwavexJazzClub located at Deviantart. Other pictures created by Quinn Hamamoto. 18 10 19