1. BELLWORK 8/28/17
#36, and 47 in your bellwork packet.

2. Measurements in Science Ch1.2
Scientists use various measurements in Science to record and express their results.
The first system of measurement that we will explore is the SI System.

3. 1. SI System
When scientists do research, they must communicate their results with each other.
In 1960, an international committee agreed upon a system of standards that would be used, and they called it, the Systeme International d’Units (SI).
In SI, there are only seven base units, with each units describing a single dimension.

4. There are 3 SI Units that we will use this year
Meter, Kilogram, and seconds,
Can you name the other 4 SI Units?

5. ANSWERS Ampere (A)– Electric current Kelvin ( K) – Temperature
Mole ( mol) – the amount of really small particles
Candela (cd) – luminous intensity

6. SI Uses Derived Units
Derived units are formed by combining the seven base units with multiplication or division. Ex: speed is measured in m/s
Ex: Force is measured in Newtons which is kg. m/s2

7. Prefixes
Scientists use prefixes to express really large or really variations of the base units.
The base unit is combined with prefixes that symbolize certain powers of 10.
Ex: The length of a housefly is 5 x 10-3m, or 5mm. The prefix milli means 10-3 power of a meter.

8. 2. Scientific Notation
The 2nd System of Measurements used by scientists is Scientific Notation.

9. The mass of one gold atom is .000 000 000 000 000 000 000 327 grams.
Scientific Notation is used to express very large and very small numbers so that problem solving will be easier.
Examples:
The mass of one gold atom is
grams.
One gram of hydrogen contains
hydrogen atoms.
Scientists can work with very large and very small numbers more easily if the numbers are written in scientific notation.

10. How to Use Scientific Notation
In scientific notation, a number is written as the product of two numbers…..
…..A coefficient and 10 raised to a power.

11. For example: 4.5 x 103 The coefficient is _______. 4.5
The number 4,500 is written in scientific notation as ________________.
4.5 x 103
The coefficient is _______.
4.5
The coefficient must be a number greater than or equal to 1 and smaller than 10.
The power of 10 or exponent in this example is _____. 3
The exponent indicates how many times the coefficient must be multiplied by 10 to equal the original number of 4,500.

12. Rules to Remember!
If a number is greater than 10, the exponent will be __________ and is equal to the number of places the decimal must be moved to the _____ to write the number in scientific notation.
positive
left

13. Rules to Remember! right
If a number is less than 1, the exponent will be ___________ and is equal to the number of places the decimal must be moved to the _______ to write the number in scientific notation.
negative
right

14. A number will have an exponent of zero if:
….the number is equal to or greater than 1, but less than 10.

15. 1. Move the decimal to the right of the first non-zero number.
To write a number in scientific notation:
1. Move the decimal to the right of the first non-zero number.
2. Count how many places the decimal had to be moved.
3. If the decimal had to be moved to the right, the exponent is negative.
4. If the decimal had to be moved to the left, the exponent is positive.
To emphasize again: The exponent counts how many places you move the decimal to the left or right.

16. Practice Problems PROBLEMS: ANSWERS 1.2 x 10-4 1 x 103 0.00012
Express the following in scientific notation.
PROBLEMS:
1.2 x 10-4
1 x 103
1 x 10-2
1.2 x 101
9.87 x 10-1
5.96 x 102
7.0 x 10-7
1.0 x 106
1.26 x 10-3
9.88 x 1011
8 x 100
ANSWERS
1000
0.01 12
0.987
596
1,000,000
987,653,000,000 8

17. EXPRESS THE FOLLOWING AS WHOLE NUMBERS OR AS DECIMALS
PROBLEMS
ANSWERS
4.9 X 102
3.75 X 10-2
5.95 X 10-4
9.46 X 103
3.87 X 101
7.10 X 100
8.2 X 10-5
490
.0375
9460
38.7
7.10

18. CLASSWORK / HOMEWORK
Complete the worksheet with a partner.