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An introduction to how to make your own simple speaker, which transmits sound from a radio or MP3 player and demonstrates the principles of electromagnetism and vibration. A detailed demonstration of how to make a cup speaker, including a discussion of materials needed. The science behind the Cup Speaker activity, including how electromagnets work, and how in this activity the magnet pushes the bottom of a cup back and forth, vibrating the air and creating sound. Exhibit developer Erik Thogersen backs away from the Giant Mirror. Watch his image change as he passes through the focal point, then continues on past the center of curvature. At the Giant Mirror, Senior Staff Scientist Paul Doherty demonstrates a simple way of locating a real image—an image that floats in space in front of the mirror. An introduction to an activity that lets you discover the secret colors hidden in black ink. With a paper towel, a black marker, and a cup of water, create a rainbow of colors while exploring capillary action and chromatography. Explore the science behind this activity, including capillary action (how the water moves up the paper) and chromatography, or how different elements of the ink are carried along at different rates, allowing you to see that black ink is actually made up of many different colors. Senior Staff Scientist Thomas Humphrey invents a simple experiment to see if the Giant Mirror is spherical or parabolic, and then to see if it's perfectly spherical. By placing a Styrofoam ball at the center of curvature, he's able to prove that the mirror is out of pure sphericity by about one-quarter of one degree. Staff Neuroscientist Richard Brown demonstrates that the Giant Mirror reflects infrared radiation as well as visible light. An introduction to the Ice Balloons activity, in which learners explore globes of frozen water and learn how to ask and then answer 'investigable' questions.