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features dozens of online learning activities and exhibits. Make a mold terrarium, pinhole projector, telescope, or hair hygrometer. Explore the brain, biodiversity, Antarctica, DNA, frogs, structures, or illusions. Learn about magnetism, electricity, motors, eyeballs, perception, Mars, chocolate, seasonings, or the science of cooking, sports, and music. Search over 3,000 photos and movies. Watch webcasts of science demonstrations by teachers. (National Science Foundation)
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The development of the chain drive helped make the bicycle that we know today possible. The chain drive eliminated the need to have the cyclist directly above the wheel. Instead the cyclist could be positioned between the two wheels for better balance. |
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Self portrait silhouettes |
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