Scientific Notation Objectives: 1. 2. Convert measurements to scientific notation. Perform calculations involving scientific notation. 3.1 Scientific Notation 1 Quiz Answer these questions. Show all your work 1. Write in scientific notation: 32000000 2. Write in scientific notation: 0.000467 3. Express 5.43 x 10-3 as a standard number 4. (4.5 x 10-14) x (5.2 x 103) = ? 5 (6.1 x 105) ÷ (1.2 x 10-3) = ? 6 (3.74 x 10-3)4 = ? 3.1 Scientific Notation 2 Quiz Answer these questions. Show all your work 1. Write in scientific notation: 32000000 2. Write in scientific notation: 0.000467 3. Express 5.43 x 10-3 as a standard number 4. (4.5 x 10-14) x (5.2 x 103) = ? 5 (6.1 x 105) ÷ (1.2 x 10-3) = ? 6 (3.74 x 10-3)4 = ? 1. 3.2 x 107; 2. 4.67 x 10-4; 3. 0.00543 4. 2.3 x 10-10 5 5.1 x 108 6. 1.96 x 10-10 3.1 Scientific Notation 3 Do Now 1. Scientists have found that there are 602,000,000,000,000,000,000,000 atoms in 1.008g of element hydrogen Numbers that are extremely large are hard to handle! a) How do you use a shorthand method to express this very large number? b) How do you name this shorthand method (shorthand notation)? 3.1 Scientific Notation 4 Do Now 2. Scientists have found that the mass of a water molecule is 0.000,000,000,000,000,000,029,91 g Numbers that are extremely small are hard to handle! a) How do you use a shorthand method to express this very small number? b) How do you name this shorthand method (shorthand notation)? 3.1 Scientific Notation 5 What is Scientific Notation? • Scientific notation is the way that scientists easily handle very large numbers or very small numbers • It is based on powers of the 10 3.1 Scientific Notation 6 General Form Scientific notation always has the following form: X 10 coefficient exponent 1 ≤ M < 10 • Coefficient: a number between 1 and 9.999… • Exponent: a positive or negative integer 3.1 Scientific Notation 7 Expressing Large Numbers • Write 501000 m in scientific notation. 501000 m can be written as 501000. m Step 1: shift the decimal point to the left until you arrive at a number between 1 and 9.999… . Drop the tailing zeros. 501000. 5 4 3 2 1 Decimal point move to the left 5.01 This number is the coefficient part Step 2: count the number of places the decimal point moved (in here 5 places). That number is the exponent part 5.01 x 10 5 m exponent coefficient 3.1 Scientific Notation 8 Expressing Large Numbers • Write 501000 m in scientific notation. 501000. 5 4 3 2 1 Decimal point move to the left 5.01 x 10 5 m exponent coefficient • A positive exponent shows that the decimal point is shifted that number of places to the left 3.1 Scientific Notation 9 Learning Check 1. Scientists estimate that there are more than 200 billion stars in the Milky Way galaxy. • How do you write this number in scientific notation? 200 000 000 000. = 2 x 1011 • Because you have moved the decimal point 11 places to the left, the exponent (power of ten) is positive 11 • A positive exponent shows that the decimal point is shifted that number of places to the left 3.1 Scientific Notation 10 Learning Check 2. The diameter of the Sun is 696,000,000 m. Write this number in scientific notation. • Begin by moving the decimal point to the left until you arrive at a number between 1 and 9.999…. In this case, 6.96, which is the coefficient part of the notation • Count how many times you had to move the decimal point to get 6.96 In this case, you have to move the decimal point 8 places to the left. This number is the exponent part. • So, in scientific notation the diameter of the Sun is 6.96 x 108 m 3.1 Scientific Notation 11 Expressing Small Numbers • Write the number 0.00002205 g in scientific notation Step 1: shift the decimal point to the right until you arrive at a number between 1 and 9.999… . 0.00002205 1 2 3 4 2.205 5 Step 2: count the number of places the decimal point moved (here 5 places). That number is the exponent part 2.205 x 10-5 g • Because you have to moved the decimal point 5 place to the right, the exponent (power of ten) is negative 5. 3.1 Scientific Notation 12 Expressing Small Numbers • Write the number 0.00002205 g in scientific notation 0.00002205 1 2 3 4 2.205 5 2.205 x 10-5 g • A negative exponent shows that the decimal point is shifted that number of places to the right 3.1 Scientific Notation 13 Learning Check 3. The radius of a hydrogen atom is 0.000000000053 m Write this number in scientific notation. • Begin by moving the decimal point to the right until you arrive at a number between 1 and 9.999…. In this case, 5.3, which is the coefficient part of the notation • Count how many times you had to move the decimal point to get 5.3 In this case, you have to move the decimal point 11 places to the right. • So, in scientific notation, the radius of a hydrogen atom is 5.3 x 10-11m 3.1 Scientific Notation 14 Learning Check 4. Diameter of a proton: 0.000 000 000 000 002 m Express this number in scientific notation 2 x 10-15 m • A negative exponent shows that the decimal point is shifted that number of places to the right 3.1 Scientific Notation 15 Understanding Scientific Notation • A positive exponent indicates a number greater than 1 Examples: • A negative exponent indicates a number between 0 and 1 (not a number less than 0) Examples: • 2000 = 2 x 103 501 = 5.01 x 102 5,216,000 = 5.216 x 106 0.005 0.0701 0.00086 = 5 x 103 = 7.01 x 102 = 8.6 x 10-4 Numbers less than 0 are indicated by putting a negative sign before the coefficient (not in the exponent) Examples: - 12500 = - 1.25 x 10 4 - 0.09024 = - 9.024 x 10 - 2 3.1 Scientific Notation 16 How Does Scientific Notation Work? • To understand how this shorthand notation works, consider the large number 30,000,000 • Mathematically, this number is equal to: 30,000,000 = 3 x 10 x 10 x 10 x 10 x 10 x 10 x 10 check this out on your calculator • We can abbreviate this chain of numbers by writing all the 10’s in an exponential form 3 x 10 x 10 x 10 x 10 x 10 x 10 x 10 = 3 x 10 7 • Note that 10 7 is the same as 10 x 10 x 10 x 10 x 10 x 10 x 10 3.1 Scientific Notation 17 How Scientific Notation Works? • • To understand how this shorthand notation works, consider the small number 0.0009 9 9 Mathematically, this 0.0009 = = number is equal to: 10000 10 ×10 ×10 ×10 check this out on your calculator • We can abbreviate this chain of numbers by writing all the 10’s in an exponential form: 9 9 = 4 10 ×10 ×10 ×10 10 Note that 10 4 is the same as 10 x 10 x 10 x 10 • Because dividing by a number is equivalent multiplying by the reciprocal of that number 9 −4 = 9 × 10 10 4 In Scientific Notation 0.0009 becomes 9 x 10 - 4 3.1 Scientific Notation 18 Reasons for Using Scientific Notation • It takes a lot less time and space to report very large or very small numbers e.g., the number of hydrogen atoms in 1g of hydrogen can be reported as 6.02 x 1023 rather than 602,000,000,000,000,000,000,000 • It also helps to represent measurements in correct number of significant figures 3.1 Scientific Notation 19 Learning Check 5. Change to scientific notation. 12,340 = 1.234 x 104 0.369 = 3.69 x 10-1 0.008 = 8 x 10-3 7,080,200,000 = 7.0802 x 109 3.1 Scientific Notation 20 Learning Check 6 Change to standard form a) 1.87 x 10–5 = 0.0000187 b) 3.7 x 108 = 370,000,000 c) 7.88 x 101 = 78.8 d) 2.164 x 10–2 = 0.02164 3.1 Scientific Notation 21 Rule for Multiplication When multiplying numbers in scientific notation, multiply the coefficients and add the exponents. Example: (3.2 x 10 - 7 m ) X (2.1 x 10 5 m ) (3.2) x (2.1) = 6.72 (10 - 7 ) x (10 5 ) = 10 ( - 7 + 5 ) = 10 - 2 6.7 x 10 - 2 m 2 Practice : (9.6 x 10 7 m ) X (1.5 x 10 4 m ) = 14.4 x 10 1 1 = 1.4 x 10 1 2m2 3.1 Scientific Notation 22 Learning Check • Multiply the coefficients and • add the exponents 7. (3.0 x 108 m) X (5.0 x 102 m) 8. (2.1 x 103 m) X (4.0 x 10-7 m) Answer # 7: (3.0 x 5.0) x 108+2 = 15 x 1010 = 1.5 x 1011m2 Answer # 8: (2.1 x 4.0) x 103 +(- 7 ) = 8.4 x 10 - 4 m 2 3.1 Scientific Notation 23 Rule for Division When dividing numbers in scientific notation, divide the coefficient in the numerator by the coefficient in the denominator. Then subtract the exponent in the denominator from the exponent in the numerator. 6.4 ×10 6 Example: 2 1.7 ×10 6 .4 = 3.8 1 .7 10 6 ( 6 - 2 ) = 10 4 = 10 10 2 Practice: 3.8 x 104 2.4 ×10 −7 -21 = 0.77 x 10 3.1×1014 3.1 Scientific Notation = 7.7 x 10-22 24 Learning Check • Divide the coefficients and, • Subtract the exponents 9. 11 1 . 5 × 10 11 8 1.5 ×10 ÷ 3.0 ×10 = 3.0 ×108 1.5 = ×10 (11−8) 3.0 = 0.50 ×10 3 = 5.0 x 102 3.1 Scientific Notation 25 Rule for Addition and Subtraction In order to add or subtract numbers written in scientific notation, you must express them with the same power of 10. 1. Find a common exponent (You may choose the larger exponent to match) 2. Then add or subtract coefficients leaving the exponent unchanged Example: (5.8 x 10 3 m L ) + (2.16 x 10 4 m L ) Since 10 3 and 10 4 not the same exponent change 5.8 x 10 3 to .58 x 10 4 = (.58 x 104) + (2.16 x 104) = 2.7 x 104 mL Practice: (8.32 x 107g) – (1.2 x 105g) 3.1 Scientific Notation = 8.3 x 107g 26 Learning Check • Find a common exponent – the exponents must be the same (You may choose the larger to match) • Then add or subtract coefficients leaving the exponent unchanged 10. (2.0 x 10 3 ) + (2.0 x 10 4 ) 11. (3.0 x 10 - 2 ) + (2.0 x 10 2 ) 10. Change 2.0 x 10 3 to 0.2 x 10 4 0.2 x 10 4 + 2.0 x 10 4 = 2.2 x 10 4 11. Change 3.0 x 10- 2 to 0.0003 x 10 2 0.0003 x 10 2 + 2.0 x 10 2 = 2.0 x 10 2 3.1 Scientific Notation 27 Using the Exponent Key on a Calculator EE EXP EE or EXP means “times 10 to the…” 3.1 Scientific Notation 28 Using Calculators Example - Change to standard form: 5 x 103 5 x 10 3 = 5 x (10 x 10 x 10) = 5 x 1000 = 5000 5 EXP 3 = = 5000 Learning Check 12. Use calculator to change to standard form a) 3.7 x 10 8 = 370,000,000 b) 7.88 x 10 1 = 78.8 3.1 Scientific Notation 29 Using Calculators Example - Change to standard form: 5 x 103 7.2 x 10 - 2 7.2 7.2 = = 10 ×10 100 7.2 EXP [+/-] 2 = =0.072 = 0.072 Learning Check 13. Use calculator to change to standard form a) 1.87 x 10–5 = 0.0000187 b) 2.164 x 10–2 = 0.02164 3.1 Scientific Notation 30 Using Calculators Example: (5.44 x 107) ÷ (8.1 x 104) How to enter this on a calculator: .. 5.44 EXP 7 8.1 EXP 4 = 671.6049383 = rounded to 6.7 x 102 Learning Check 14. Use calculator to solve this problem (6.2 x 10-3) x (1.5 x 101) = 9.3 x 10-2 3.1 Scientific Notation 31 Using Calculators −3 6 ( 3 . 8 × 10 ) × ( 1 . 2 × 10 ) Example: 8.0 ×10 4 How to enter this on a calculator: 3.8 EXP [+/-] 3 X 1.2 EXP 6 . . 8.0 EXP 4 = = 0.057 5.7 x 10 - 2 Learning Check 15. Use calculator to solve this problem 6.6 ×10 6 (8.8 ×10 −2 ) × (2.5 ×103 ) = 3.0 x 104 3.1 Scientific Notation 32