1. The Scientific Method
Mr. Luis A. Velazquez

2. What is the scientific method?
Is a step by step process to understand nature.
Scientists use an experiment to search for cause and effect relationships in nature.
In other words, they design an experiment so that changes to one item cause something else to vary in a predictable way.

3. What are the steps in the scientific method?
Define the problem
Gather information
Make an hypothesis
Test your hypothesis
Review your results
Make a conclusion

4. What are variables?
In an experiment these changing quantities are called variables, and an experiment usually has three kinds:
independent
dependent
control

5. The control variable
Controlled variables are quantities that a scientist wants to remain constant, and he must observe them as carefully as the dependent variables. Why?
Most experiments have more than one controlled variable.
Some people refer to controlled variables as "constant variables."

6. The Independent Variable
The independent variable is the one that is changed by the scientist.
In an experiment there is only one independent variable.

7. The dependent variable
The dependent variable changes in response to the change the scientist makes to the independent variable.
The number of dependent variables in an experiment varies, but there is often more than one.

8. Examples:
“For example, if you open a faucet (the _________ variable), the quantity of water flowing (__________ variable) changes in response-the water flow increases.”

9. How to identify the dependent variable?
To be predicted
The response variable
The outcome
A variable that is not under the experimenter's control.

10. Difference between Variables
Independent
Only one
Input
Manipulated var
Is under the control of the Experimenter
Cause
Dependent
One or more
Output
Response var
Results and data
Not controled
Effects

11. How to identify the independent variable?
The cause
The input
The manipulated variable
The variable that is changed on purpose in an experiment.

12. if we want to measure how much water flow increases when we open a faucet, it is important to make sure that the water pressure (the controlled variable) is held constant.
That's because both the water pressure and the opening of a faucet have an impact on how much water flows.
If we change both of them at the same time, we can't be sure how much of the change in water flow is because of the faucet opening and how much because of the water pressure.
Most experiments have more than one controlled variable.

13. The SI Unit System
Mr. Luis A. Velazquez

14. PREFIX
SYMBOL
FACTOR
yotta Y
1024
zetta Z
1021
exa E
1018
peta P
1015
tera T
1012
giga G
109
mega M
106

15. PREFIX
SYMBOL
FACTOR
kilo K
103
hecto H
102
deka D
101
deci d
10-1
centi c
10-2
milli m
10-3
micro
10-6
nano n
10-9
pico p
10-12
femto f
10-15
atto a
10-18
zepto z
10-21
yocto y
10-24

16. Prefix Kilo 10x 10 x 10 = 1000 = 103 Hecto 10 x 10 = 100 = 102
Decka x1 = = 101
deci /10 = = 10-1
centi /100 = = 10-2
milli /1000 = = 10-3
1x1 = =

17. How to remember? K H D d c m Basic unit King Henry Died Drinking
Chocolate
Milk H
Basic unit D d
mass, length, volume c m

18. Basic Unit Kilo Left Hecto Decka Grams, Liters, meter deci centi Right
milli

19. Practice Problems 5 Kg =_______ g 5000 3 Answer 5000
Kilograms are bigger than Grams
So you need to multiply this means you move the decimal to the right
How many times?
5 Kg =_______ g
5000 3
Answer
5000

20. Practice Problems .045 cg =_______ g .00045 2 Answer .00045
centigrams are smaller than grams
So you need to divide this means you move the decimal to the left
How many times?
.045 cg =_______ g
.00045 2
Answer
.00045

21. Practice Problems 36 Dg =_______ g 360 1 Answer 360
Dekagrams are bigger than grams
So you need to multiply this means you move the decimal to the right
How many times?
36 Dg =_______ g
360 1
Answer
360

22. Practice Problems 7 mg =____________ Kg 0.000007 6 Answer 0.000007
milligrams are smaller than Kilograms
So you need to divide this means you move the decimal to the left
How many times?
7 mg =____________ Kg 6
Answer

23. Practice Problems 9 L =_______ mL 9000 3 Answer 9000
Liters are bigger than milliliters
So you need to multiply this means you move the decimal to the right.
How many times?
9 L =_______ mL
9000 3
Answer
9000

24. Answer tofollowing Problems
35L = KL
46 g = Hg
mg = Dg
9.53 mm = m
7.908 cL = L
0.521 Hm = cm

25. 35L = KL
Liter are smaller than Kiloliters so you divide or move your decimal to the left.
You move your decimal to the left three times
The answer is .035 KL

26. 46 g = Hg
Grams are smaller than Hectograms so you divide or move your decimal to the left.
You move your decimal to the left two times .
The answer is 0.46Hg or .46 Hg

27. mg = Dg
milligrams are smaller than Decagrams so you divide or move you decimal to the left.
You move your decimal to the left four times.
The answer is Dg

28. 9.53 mm = m
millimeters are smaller than meter so you divide or move you decimal to the left.
You move your decimal to the left three times
The answer is meters

29. 7.908 cL = L
centiliters are smaller than Liters so you divide or move you decimal to the left.
You move your decimal to the left two times.
The answer is Liters

30. 0.521 Hm = cm
Hectometer are bigger than centimeters so you multiply or move you decimal to the right.
You move your decimal to the right four times.
The answer is cm