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The Scientific MethodThe Scientific MethodThe Scientific MethodThe Scientific MethodMr. Luis A. VelazquezMr. Luis A. Velazquez
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.
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
• In an experiment these changing quantities are called variables, and an experiment usually has three kinds:
• independent• dependent• control
What are variables?
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."
The Independent Variable
• The independent variable is the one that is changed by the scientist.
• In an experiment there is only one independent variable.
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.
How to identify the dependent variable?
• To be predicted• The response variable• The outcome• A variable that is not under the
experimenter's control.
• The cause• The input• The manipulated variable• The variable that is changed on
purpose in an experiment.
How to identify the independent variable?
Difference between Variables
• Dependent– One or more– Output– Response variable– Results and data– Not controlled
– Effects
• Independent– Only one– Input– Manipulated variable– Is under the control
of the scientist
– Cause
The SI Unit SystemThe SI Unit SystemThe SI Unit SystemThe SI Unit SystemMr. Luis A. VelazquezMr. Luis A. Velazquez
PREFIX SYMBOL FACTOR
yotta Y 1024
zetta Z 1021
exa E 1018
peta P 1015
tera T 1012
giga G 109
mega M 106
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
Prefix• Kilo 10x 10 x 10 = 1000 = 103
• Hecto 10 x 10 = 100 = 102
• Decka 10x1 = 10 = 101
• deci 1/10 = 0.1 = 10-1
• centi 1/100 = 0.01 = 10-2
• milli 1/1000 = 0.001 = 10-3
1x1 = 1 = 100
How to remember?
• King • Henry • Died
• Drinking• Chocolate • Milk
Basic unit
K
H
D
dc
m
mass, length, volume
Practice Problems
Kilograms are bigger than Grams So you need to multiply this means you
move the decimal to the right How many times? 3
5 Kg =_______ g
Answer 5000
5000
Practice Problems
centigrams are smaller than grams So you need to divide this means you
move the decimal to the left
How many times?2
.045 cg =_______ g
Answer .00045
.00045
Practice Problems
Dekagrams are bigger than grams So you need to multiply this means you
move the decimal to the right
How many times?1
36 Dg =_______ g
Answer 360
360
Practice Problems
milligrams are smaller than Kilograms So you need to divide this means you
move the decimal to the left
How many times?6
7 mg =____________ Kg
Answer 0.000007
0.000007
Practice Problems
Liters are bigger than milliliters So you need to multiply this means you
move the decimal to the right.
How many times?3
9 L =_______ mL
Answer 9000
9000
Answer tofollowing Problems
• 35L = .035 KL• 46 g = .46 Hg• 0.000015mg = .0000000015 Dg• 9.53 mm = .00953 m• 7.908 cL = .07908 L• 0.521 Hm = 5210
cm
• 35L = .035 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
• 46 g = 0 .46 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
0.000015mg = .0000000015 Dgmilligrams 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 .0000000015 Dg
9.53 mm = .00953m 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 .00953 meters
• 7.908 cL = .07908L 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 .07908 Liters