mess 341 microscopic 阅读理解: gamma wavelengths of 第十三篇 Invisibility Ring microwaves are shorter thanthose of Scientists can’t yet make an radio waves but longer than those of invisibility cloak1 like the one that visible light. Harry Potter2 ,for the first The scientists ’ new time,they’ve constructed a simple “invisibility device” is the size of cloaking device that makes itself a drink coaster and shaped like and somethingplaced inside it ring is made of a special invisible to microwaves. material with unusual When a person “sees” an microwaves strike thering,very few object,his or her eye senses many bounce off , they pass different waves of visiblelight as through the ring,which bends the they bounce off the eye waves allthe way around until they and brain then work together to reach the opposite waves organize thesesensations and then return to their originalpaths. reconstruct the object’s original To a detector set up to receive shape. So , to make an object microwaves on the other side of the invisible,scientists have to keep ring,it looks as if thewaves never waves from bouncing off changed their paths as if there were they have to make sure the no object in the way! So,the ring is objectcasts no , effectively invisible. the absence of reflected light on one When the researchers put a side would give the obiectaway. small cdpper loop inside the ring,it , Invisibility isn’t possible yet too,is nearly invisible. However, with waves of light that the human the cloaking device and anything eye can it is nowpossible inside it do cast a pale with visible light, the deviceworks only for microwaves are a form of radiant micro