1. BELLWORK 8/16/16
What is the SI unit for length?
Mass?
Time?

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 Measurements (cont)
These units are defined by the standards described in Table 2 and are reproduced so that every meterstick, kilogram mass, and clock in the world is calibrated to give consistent results.

7. 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

8. 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.

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

10. 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.

11. 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.

12. 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.

13. 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

14. 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

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

16. 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.

17. 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

18. 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

19. EXPLORE ACTIVITY
You will receive a number written as a decimal or in scientific notation.
You must find the person who has the same value in the shortest amount of time possible.
Your class will form a circle as you partner up with your match.
The time will stop as soon as the “Class Rep” gives me the thumbs up sign.
There is ONE CATCH……………………………

20. ONE CATCH………. YOU MAY NOT TALK!!!!!!!
IF I HEAR ANY TALKING- YOU WILL BE DISQUALIFIED.
THE WINNING CLASS (THE CLASS WHO CAN FIND ALL OF THEIR MATCHES AND CIRCLE UP IN THE SHORTEST AMOUNT OF TIME) WILL WIN A PRIZE!!!!!

21. Reinforcement
There is a scientific notation worksheet on my webpage if you need extra practice.