Invisibility RingScientists cant yet make an invisibility cloak1 like the one that Harry Potter2 uses.But，for the first time，theyve constructed a simple cloaking device that makes itself and somethingplaced inside it invisible to microwaves.
Invisibility isnt possible yet with waves of light that the human eye can see.But it is nowpossible with microwaves.Like visible light，microwaves are a form of radiant energy.Theyare part of the electromagnetic spectrum，which also includes radio waves，infrared light，ultraviolet rays，X rays，and gamma rays.The wavelengths of microwaves are shorter thanthose of radio waves but longer than those of visible light.
To a detector set up to receive microwaves on the other side of the ring，it looks as if thewaves never changed their paths as if there were no object in the way! So，the ring is effectively invisible.
词汇：
cloak斗篷，披风 infraredadj.红外线的5maikrEuweivp
reconstructv.重建 gamma ray 伽马射线5reidjEnt5weivleNWp
electromagneticadj.电磁的coastern.托盘，垫子
1.Harry Potter is mentioned in the passage，because scientists
Btry to make an invisible cloak of the same kind as he uses.
Dknow that it is possible to make an invisible cloak of the same kind.
ATheir wavelengths are shorter than those of visible light.
CThey are different from visible light as they are a kind of radiant energy.
人教版英语八下Unit 2《I’ll help to clean up the city park》Section B 2b
人教版英语八下Unit 2《I’ll help to clean up the city park》课件5
人教版英语八下Unit 1《What’s the matter》课件15
人教版英语八下Unit 10《I’ve had this bike》（Section B 1c）课文朗读
人教版英语八下Unit 2《I’ll help to clean up the city park》Section A 3a
人教版英语八下Unit 10《I’ve had this bike》（Section A-1）课件
人教版英语八下Unit 2《I’ll help to clean up the city park》Section B 2a
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人教版英语八下Unit 2《I’ll help to clean up the city park》（Section A 2a）课文朗读
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人教版英语八下Unit 2《I’ll help to clean up the city park》（Section A 2b）课文朗读
人教版英语八下Unit 10《I’ve had this bike》（Section B 1b）课文朗读
人教版英语八下Unit 2《I’ll help to clean up the city park》Section A 2b
人教版英语八下Unit 1《What’s the matter》课件
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人教版英语八下Unit 2《I’ll help to clean up the city park》Section A 2
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人教版英语八下Unit 2《I’ll help to clean up the city park》words
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人教版英语八下Unit 2《I’ll help to clean up the city park》Self check
人教版英语八下Unit 2《I’ll help to clean up the city park》课件
人教版英语八下Unit 2《I’ll help to clean up the city park》Section A 2a
人教版英语八下Unit 2《I’ll help to clean up the city park》Section B 2
人教版英语八下Unit 1《What’s the matter》课件2
人教版英语八下Unit 10《I’ve had this bike》（Self Check）课件
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