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Science Starter Week 9- Day 1 (4/4/16)
1. What would be the best way to
calculate how many peanuts are in this
container?
2. How many eggs in a dozen? In a gross?
3. How many protons, neutrons, and
electrons in a neutral atom of C-13?
4. How far away is the sun from Earth?
Objective
• SWBAT use dimensional analysis to solve
conversion problems
• SWBAT put numbers into scientific notation from
standard and vice versa.
• SWBAT fix incorrect scientific notation
• SWBAT multiply and divide numbers in scientific
notation.
Agenda
• Science Starter
• Dimensional Analysis
• Scientific Notation
–Converting from standard to SciNote and vice versa
–Multiplying/Dividing
• Exit Ticket/Homework
Announcements
• Today: Conversions & Scientific Notation
• Tuesday: Intro to the Mole
• Wednesday: Molar Conversions (1 & 2)
• Thursday: Molar Conversions Quiz
• Friday: Empirical/Molecular Formulas
Unit 5: The Mole
Dimensional Analysis
What you’re given
in problem
Find unit
Given unit
The thing in the “fraction” is CONSTANT—we
call this a conversion factor.
Practice
Remember:
Set it up as a dimensional analysis problem!
1. How many eggs in 4 dozen?
2. How many days in 350,000 seconds?
Unit 5: The Mole
Scientific Notation
Think about it…
• The growth of a fingernail is 0.000015 millimeters per hour
• The sun’s temperature reaches 27,000,000 degrees Fahrenheit.
• The distance from the Earth to the Sun is about 93,000,000 miles.
Would you want to compute math
problems with these crazy numbers??
What can we do to make these
more manageable?
Background Info
Scientific Notation!!!
• Scientific notation is a way of writing a number as a
multiplication problem where..
The first number is
no smaller than 1 and less than 10 (decimals ok)
And
The second number is a power of 10
Anatomy of A Number in
Scientific Notation
Steps
Time to practice your SHORTHAND!!!
1) Place decimal point so that there is only one nonzero number to the left of the decimal point.
2) Count the number of decimal places the decimal
has “moved”. This will be your exponent.
3) If the original number was less than 1, the
exponent will be negative. If it was greater than 1,
the exponent will be positive.
Example
The growth of a fingernail is measured in 0.000015 millimeters per hour
Example: Let’s put 0.000015 in scientific notation.
0.000015 
How many times did we move the decimal point?
Since the original number was less than one, the exponent
will be negative.
Example
• The distance from the Earth to the Sun is about 93,000,000 miles.
Example: Let’s put 93,000,000 in scientific notation.
93,000,000 
How many times did we move the decimal point?
Since the original number was greater than one, the exponent
will be positive.
Partner Practice
Convert the following into scientific notation:
61,500 kg
0.00043 mm
1,000,000 protons
0.0345 grams
Fixing Numbers in Scientific Notation
35.6 x 106
0.078 x 105
640 x 10-4
0.0004 x 10-19
Multiplying
• To multiply two numbers written in scientific notation:
–Multiply the first two numbers
–Add the exponents
–Adjust the leading number as needed.
Example: 1.02 x 105 x 3.43 X 10-4
Partner Practice
2 x 106 X 4 x 102
Dividing
• To divide two numbers written in scientific notation:
–Divide the first two numbers
–Subtract the exponents
–Adjust the leading number as needed.
• Example: 8.496 x 107
3.6 x 10-8
Partner Practice
5
10
6.0 x
2
3.0 x 10
Homework 5.1