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Vocabulary Science and Technology_02

Tham khảo tài liệu 'vocabulary science and technology_02', ngoại ngữ, ngữ pháp tiếng anh phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | WORD FORMS To correctly complete each sentence rewrite each boldface word in a different form. 1. evaporation On a sunny day water in a puddle will quickly. 2. extinct Mass occurs when many forms of life suddenly disappear from the Earth. 3. environment are those who work to protect Earth s air and water from pollution. 4. condensation Freezing temperatures water into ice. ANALOGIES Remember that analogies are statements of relationship. Begin by thinking about the relationship between the first two words. Then complete the analogy by writing the glossary word that makes sense. 1. Human being is to frog as warm-blooded is to _c_ 2. Past is to present as is to living. 3. Daisy is to flower as sleet is to _p_ 4. Venus is to planet as moon is to _s_ 5. Environment is to environmental as continent is to c__ 6. Circulation is to circulatory as r is to respiratory. 33 UNIT 2- Lesson 2 SCIENCE AND TECHNOLOGY WORDS What s a Hertz A hertz is the standard unit of frequency used to measure an energy wave. Suppose you were watching a child on a swing. Each cycle of swing-out and swing-in would be one cycle. If you kept track of time while you watched you could measure the swing in hertz. Two in-and-out cycles per second would be 2-hertz or 2Hz. Household electricity is usually 120 volts at 60Hz which means it pulses energy at 60 times per second. Kilohertz means thousands of cycles per second. AM radio broadcasts in kHz. Its programs are transmitted on waves that number 740 000 per second. Megahertz or MHz means millions of cycles per second. Cordless phones broadcast as radio signals that cycle at millions of times a second. Computer processors run at speeds of about 450 million cycles per second. Where did the word hertz come from It came from a German physicist named Heinrich Hertz. In the late 1800s he was the first to produce electromagnetic waves