English for physicists. Лидия Страутман

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СКАЧАТЬ measurements of the physical world vary so tremendously in size (imagine trying to describe the distance across the United States in units of hair thicknesses), physicists often times use what is known as scientific notation to denote very large and very small numbers. These very large and very small numbers would become quite cumbersome to write out repeatedly. Imagine writing 4,000,000,000,000 over and over again. Your hand would get tired and your pen would rapidly run out of ink! Instead, it's much easier to write this number as 4×10¹². See how much easier that is? Or on the smaller scale, the thickness of the insulating layer (known as a gate dielectric) in the integrated circuits that power our computers and other electronics can be less than 0.000000001 m. It's easy to lose track of how many zeros you have to deal with, so scientists instead would write this number as 1×10^-9 m. See how much simpler life can be with scientific notation?

      Scientific notation follows these simple rules. Start by showing all the significant figures in the number you're describing, with the decimal point after the first significant digit. Then, show your number being multiplied by 10 to the appropriate power in order to give you the correct value.

      It sounds more complicated than it is. Let's say, for instance, you want to show the number 300,000,000 in scientific notation (a very useful number in physics), and let's assume we know this value to three significant digits. We would start by writing our three significant digits, with the decimal point after the first digit, as «3.00». Now, we need to multiply this number by 10 to some power in order to get back to our original value. In this case, we multiply 3.00 by 10⁸, for an answer of 3.00×10⁸. Interestingly, the power you raise the 10 to is exactly equal to the number of digits you moved the decimal to the left as you converted from standard to scientific notation. Similarly, if you start in scientific notation, to convert to standard notation, all you have to do is remove the 10⁸ power by moving the decimal point eight digits to the right. Now you are an expert in scientific notation!

      But, what do you do if the number is much smaller than one? The same basic idea… let's assume we're dealing with the approximate radius of an electron, which is 0.00000000000000282 m. It's easy to see how unwieldy this could become. We can write this in scientific notation by writing our three significant digits, with the decimal point after the first digit, as «2.82». Again, we multiply this number by some power to 10 in order to get back to our original value. Because our value is less than 1, we need to use negative powers of 10. If we raise 10 to the power -15, specifically, we get a final value of 2.82×10^-15 m. In essence, for every digit we moved the decimal place, we add another power of 10. And if we start with scientific notation, all we do is move the decimal place left one digit for every negative power of (to) 10.

      VII. Answer the questions on the text

      1. In what way are physics and mathematics related?

      2. What is meant by scientific notation?

      3. What rules does it follow?

      4. How many positions do you need to show the numbers in scientific notation?

      5. Express the number 0.000470 in scientific notation.

      Express the number 2,870,000 in scientific notation.

      UNIT 2

      Vocabulary

      to involve v. – 1) вовлекать; включать в себя

      2) быть связанным с ч-л.;

      prediction n. – предположение; предсказание phenomenon n. – явление;

      to communicate v. – 1) сообщаться; 2) держать связь; 3) сообщение;

      data n. – данные, сведения to set v. – комплектовать;

      to standardize v. – стандартизировать;

      to define v. – 1) определять; 2) давать определение;

      3) устанавливать;

      unit n. – 1) единица (оборудования); 2) блок;

      3) установка;

      current n. – 1) ток (эл.); 2) a. современный;

      to form the foundation – образовывать основание;

      to refer v. – 1) ссылаться (на), 2) упоминать;

      to focus v. – концентрировать(ся), сосредоточивать(cя);

      to introduce v. – представлять;

      length n. – 1) длина; 2) отрезок, кусок;

      to divide (into) – делить (на);

      to make up – составлять;

      wire n. – проволока, провод;

      paperclip n. – скрепка для бумаг;

      to break up – разбивать; разрушать familiar adj. – хорошо известный, знакомый to be based on – быть основанным на ч. – л.;

      I. Practice pronunciation of the following words:

      analysis [ə'nalɪsɪs] approximately [ə'prɒksɪmətli]

      specific [spə'sɪfɪk] length [lɛŋθ]

      standarize ['stændərdaɪz] equivalent [ɪ'kwɪv(ə)l(ə)nt]

      meter ['mi: tə] cube [kju: b]

      kilogram [ 'kɪləɡram] microsecond ['mʌɪkrə(ʊ),sɛkənd]

      second ['sɛk(ə)nd] extremely [ɪk'stri: mli ]

      ampere ['ampɛ:] valuable ['valjʊb(ə)l]

      roughly ['rʌfli] chart [tʃɑ:t]

      II. Read and translate the words having the same root communicate – communication, measure – measurement, define – definition, found – foundation, introduce – introduction – introduced, divide – division – divided, convert – conversion.

      III. Make the following nouns plural

      Phenomenon, basis, analysis, datum, thesis, ampere, radius, medium, index.

      IV. Complete the sentences with the following words given below

      1. ___________is considered to be the most basic of the natural sciences.

      2. It СКАЧАТЬ