Objective/Warm-up

1
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

2
Notes-Accuracy
Word/Phrase Definition
Hints or diagram Meaning in My own words
How close the measurement is to the real, true,
or correct value
accuracy
correctness
3
Notes-Precision
Word/Phrase Definition
Hints or diagram Meaning in My own words
precision
How close measurements are to each other
repeatable
4

• 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.

5
Scientific Notation
A short-hand way of writing large numbers
without writing all of the zeros.
6
The Distance From the Sun to the Earth
93,000,000
7
Large Numbers
8
Step 1

• Move decimal left
• Leave only one number in front of decimal

93,000,000 9.3000000
9
Step 2

• Write number without zeros

93,000,000 9.3
10
Step 3

• Count how many places you moved decimal
• Make that your power of ten

11
The power of ten is 7 because the decimal moved
7 places.
12

• 93,000,000 --- Standard Form
  
• 9.3 x 107 --- Scientific
  Notation

13
Practice Problem
Write in scientific notation. Decide the power
of ten.

1. 98,500,000 9.85 x 10?
2. 64,100,000,000 6.41 x 10?
3. 279,000,000 2.79 x 10?
4. 4,200,000 4.2 x 10?

14
More Practice Problems
On these, decide where the decimal will be moved.

1. 734,000,000 ______ x 108
2. 870,000,000,000 ______x 1011
3. 90,000,000,000 _____ x 1010

Answers
3) 9 x 1010

1. 7.34 x 108

2) 8.7 x 1011
15
Complete Practice Problems
Write in scientific notation.

1. 50,000
2. 7,200,000
3. 802,000,000,000

Answers
1) 5 x 104
2) 7.2 x 106
3) 8.02 x 1011
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Scientific Notation to Standard Form
Move the decimal to the right

• 3.4 x 105 in scientific notation

• 340,000 in standard form

17
Write in Standard Form
Move the decimal to the right.

• 6.27 x 106
• 9.01 x 104

• 6,270,000
• 90,100

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Small Numbers
19
Step 1

• Move decimal right
• Leave only one number in front of decimal

0.000324 00003.24
20
Step 2

• Write number without zeros

0.000324 3.24
21
Step 3

• Count how many places you moved decimal
• Make that your power of ten

22
The power of ten is -4 because the decimal moved
4 places.
23

• 0.000324 --- Standard Form
  
• 3.24 x 10-4 --- Scientific
  Notation

24
Practice Problem
Write in scientific notation. Decide the power
of ten.

1. 0.000000985 9.85 x 10?
2. 0.641 6.41 x 10?
3. 2.79 2.79 x 10?
4. 0.042 4.2 x 10?

25
Complete Practice Problems
Write in scientific notation.

1. 0.005
2. 0.000072
3. 0.000802

Answers
1) 5 x 10-3
2) 7.2 x 10-5
3) 8.02 x 10-4
26
Scientific Notation to Standard Form
Move the decimal to the left

• 3.4 x 10-5 in scientific notation

• 0.000034 in standard form

27
Write in Standard Form
Move the decimal to the left.

• 6.27 x 10-6
• 9.01 x 10-4

• 0.00000627
• 0.000901

28
Scientific Notation Examples

• Change from scientific notation
• the distance from Pluto to the Sun is 5.910 12
  meters
• the Milky Way disk radius is 3.91020 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

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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