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Learn to distinguish between accuracy and precision, use scientific notation, and determine the number of significant figures in each number. Discuss the unfairness of reporting percentage weight loss in the TV show "The Biggest Loser" and suggest a correction. Practice problems included.
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Objective/Warm-up • Students will be able to distinguish between accuracy and precision. • Students will be able to use scientific notation. • How many sig figs in each number? • 3.400 • 0.00304 • 0.34090 • 0.0030 • 4500
Notes-Accuracy How close the measurement is to the real, true, or correct value accuracy correctness
Notes-Precision precision How close measurements are to each other repeatable
On the TV show “The Biggest Loser”, weight loss is reported in whole pounds, but percentage weight loss is given with two decimal places. For example, if a 210 lb. person lost 4 pounds, the percent weight loss is reported as 1.90% weight loss. Write a letter to the producers of the show to explain how this is unfair and not correct precision in reporting the percentage weight loss. Suggest a way to correct this for future shows.
Scientific Notation A short-hand way of writing large numbers without writing all of the zeros.
The Distance From the Sun to the Earth 93,000,000
Step 1 • Move decimal left • Leave only one number in front of decimal 93,000,000 = 9.3000000
Step 2 • Write number without zeros 93,000,000 = 9.3
7 93,000,000 = 9.3 x 10 Step 3 • Count how many places you moved decimal • Make that your power of ten
The power of ten is 7 because the decimal moved 7 places. 7 93,000,000 = 9.3 x 10
93,000,000 --- Standard Form • 9.3 x 107 --- Scientific Notation
9.85 x 107 -----> 6.41 x 1010 -----> 2.79 x 108 -----> 4.2 x 106 -----> Practice Problem Write in scientific notation. Decide the power of ten. • 98,500,000 = 9.85 x 10? • 64,100,000,000 = 6.41 x 10? • 279,000,000 = 2.79 x 10? • 4,200,000 = 4.2 x 10?
More Practice Problems On these, decide where the decimal will be moved. • 734,000,000 = ______ x 108 • 870,000,000,000 = ______x 1011 • 90,000,000,000 = _____ x 1010 Answers 3) 9 x 1010 • 7.34 x 108 2)8.7 x 1011
Complete Practice Problems Write in scientific notation. • 50,000 • 7,200,000 • 802,000,000,000 Answers 1) 5 x 104 2) 7.2 x 106 3) 8.02 x 1011
3.40000 --- move the decimal ---> Scientific Notation to Standard Form Move the decimal to the right • 3.4 x 105 in scientific notation • 340,000 in standard form
6.27 x 106 9.01 x 104 6,270,000 90,100 Write in Standard Form Move the decimal to the right.
Step 1 • Move decimal right • Leave only one number in front of decimal 0.000324 = 00003.24
Step 2 • Write number without zeros 0.000324 = 3.24
-4 0.000324 = 3.24 x 10 Step 3 • Count how many places you moved decimal • Make that your power of ten
The power of ten is -4 because the decimal moved 4 places. -4 0.000324 = 3.24 x 10
0.000324 --- Standard Form • 3.24 x 10-4 --- Scientific Notation
9.85 x 10-7 -----> 6.41 x 10-1 -----> 2.79 x 100 -----> 4.2 x 10-2 -----> Practice Problem Write in scientific notation. Decide the power of ten. • 0.000000985 = 9.85 x 10? • 0.641 = 6.41 x 10? • 2.79 = 2.79 x 10? • 0.042 = 4.2 x 10?
Complete Practice Problems Write in scientific notation. • 0.005 • 0.000072 • 0.000802 Answers 1) 5 x 10-3 2) 7.2 x 10-5 3) 8.02 x 10-4
000034 --- move the decimal <--- Scientific Notation to Standard Form Move the decimal to the left • 3.4 x 10-5 in scientific notation • 0.000034 in standard form
6.27 x 10-6 9.01 x 10-4 0.00000627 0.000901 Write in Standard Form Move the decimal to the left.
Scientific Notation Examples Change from scientific notation • the distance from Pluto to the Sun is 5.9×10 12 meters • the Milky Way disk radius is 3.9×1020 meters. • The speed of light is 3 x 10 8 meters/second. • the sun is 1.5x 1011 meters from earth • Mass of proton : 1.6726 x 10-27 kg • Mass of neutron: 1.6749 x 10-27 kg • Mass of electron: 9.10939 × 10-31 kg Change into scientific notation • 0.000 000 000 753 kg. is the mass of a dust particle! • A proton has a diameter of approximately 0.000000000001 mm
Quick Review • When adding or subtracting: • Make sure the exponents are the same and line up the decimal points. • When multiplying: • Add the exponents • When dividing: • Subtract the exponents