服务承诺
资金托管
原创保证
实力保障
24小时客服
使命必达
51Due提供Essay,Paper,Report,Assignment等学科作业的代写与辅导,同时涵盖Personal Statement,转学申请等留学文书代写。
51Due将让你达成学业目标
51Due将让你达成学业目标
51Due将让你达成学业目标
51Due将让你达成学业目标私人订制你的未来职场 世界名企,高端行业岗位等 在新的起点上实现更高水平的发展
积累工作经验
多元化文化交流
专业实操技能
建立人际资源圈Microwaves
2013-11-13 来源: 类别: 更多范文
Microwaves
The microwave oven is one of the many inventions that were not intentionally created. In the mid-nineteen forties, during World War II the magnetron tube was invented. This device produced microwaves. A microwave is a radio wave. They were installed in British radar systems to detect Nazi warplanes in the British Isles. Several years later, scientists discovered that microwaves cooked food.
The idea came across of using these microwaves for heating food when Dr. Percy Spencer was testing one of the magnetron tubes and the candy bar in his pocket melted. That is because the wave frequency of the microwave is 2,500 megahertz. Water, fats and sugars absorb this frequency. This occurrence converts the microwaves into atomic motion, which is heat. Another interesting property about this frequency range is that most plastic glass and ceramics do not absorb it. Dr. Spencer then did experiments in front of other colleagues with eggs and popcorn. This proved microwave heating could raise food temperatures faster than a conventional oven. Dr. Spencer then created a metal box, which he designed to trap energy. The microwave energy was not able to escape. This higher concentration of energy caused the
microwave, oven, ovens, microwaves, homes, one, new, food, water, cooking, time, technology, spencer, price, heating, first, energy, dr, cup, being, because, soon, radiation, possible, person, people, over, now, magnetron, idea, heated, heat, frequency, faster, dry

