The Scientific
Method/Process
By Mr. Victor M. Calzada
Vocabulary
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scientific method
hypothesis
testable
independent variable
dependent variable
control variable
observations
data
symmetry
distance
mass
temperature
volume
time
What is Science?
What is Science?
What is
• Science is having curiosity of our natural world,
asking question over it and finding
answers/solutions to them by using a systematic
process to investigate them. That new
knowledge/information is used to develop new
ideas and technology to better our lives.
The Scientific Method
• The Scientific Method is the process used to find those answers to the
questions we are curious about.
• Scientists use the Scientific Method to compare new ideas/knowledge with
other scientists.
• It makes our lives a lot better!
The Scientific Method
• Remember that science comes from our curiosity about the world.
Whenever someone has a question about how something works, what
it is, where it comes from etc., they start with a good question.
• Example:
• “Does water temperature affect how fast sugar cubes dissolve?”
• “Do different types of soils affect the growth a marigold plant?”
• “How much water each day does a tomato plant need to produce fruit?”
Step 1. Problem
• Problem in the form of a question.
• A good question must be:
• specific and well defined
• have only 1 independent variable
• must be testable
• observable - use your five senses (hearing, tasting, smelling, tactile, sight)
• measurable – be able to test your problem by finding an object’s mass,
weight, volume, length, density, etc
• must have the materials to conduct the investigation
What are variables?
• 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 in a predictable way.
• A variable is any factor, trait, or condition that can exist in differing amounts or types.
• An experiment usually has three kinds of variables:
• independent variable
• dependent variable
• controlled variable
Independent Variable
• The independent variable is the one that is changed by the scientists.
• To ensure a fair test, a good experiment has only one independent variable
• As the scientist changes the independent variable, or she observes what
happens.
• It is the cause of the experiment.
Independent Variable
• Example:
• “Does water temperature affect how fast sugar cubes dissolve?”
• The independent variable is the water temperature because it
is the cause of the experiment.
• It is the variable in the experiment that is different between the
tests.
Independent Variable
Cause:
Test 1
30 ˚C
Test 2
20 ˚C
Test 3
50 ˚C
IV: the
temperature of
the water
Dependent Variable
• The scientist focuses his or her observations on the dependent variable to
see how it responds to the change made to the independent variable.
• The dependent variable is the effect/result of the experiment.
• Example:
• “Does water temperature affect how fast sugar cubes dissolve?”
• The dependent variable is how fast the sugar cubes dissolve (time).
Dependent Variable
Effect:
DV: time it takes for the
sugar cubes to dissolve
Cause:
Test 1
30 ˚C
Test 2
20 ˚C
Test 3
50 ˚C
IV: the
temperature of
the water
Controlled Variable
• Experiments also have controlled variables.
• Control variables are quantities or amounts that a scientist wants
to remain constant.
• A controlled variable stays the same between the tests!
• A scientist can have as many as they want.
• A controlled variable does not cause results.
Dependent Variable
Effect:
DV: time it takes for the
sugar cubes to dissolve
Never cause results/effects:
CV:
Amount of water
Same type of water
Amount of sugar cubes
same size cups
Cause:
Test 1
30 ˚C
Test 2
20 ˚C
Test 3
50 ˚C
IV: the
temperature of
the water
Step 2: Research
• Conduct some research over your question/problem.
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• Learn more about your question before you conduct an investigation over it.
• Learn more about your question before you develop a hypothesis over it.
• Use the following resources to learn more about your problem:
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encyclopedias
Internet
dictionaries
magazines/newspapers
Step 3: Hypothesis
• Develop a hypothesis.
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• It is a prediction or educated guess. This is what you think the answer to your
question/problem will be. The hypothesis has to be based on research that you have
previously done over your problem.
• Remember, it has to be testable!
• Remember the hypothesis doesn’t have to be correct because an investigation has
not been conducted over it yet.
Hypothesis
• Example:
• “The sugar cube in the 30 ° Celsius test
will dissolve faster because increasing heat
causes substances to dissolve faster”
Step 4: Plan to test the hypothesis
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We first plan to test the hypothesis before we conduct an investigation.
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Plan to gather your materials for the investigation.
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You have to be specific about the amounts of materials needed.
• Example: 5 milliliters of water
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You also have to be specific about the types of materials needed.
• Example: Instead of saying you need potting soil, state that you need 5 milliliters of Miracle Grow Potting Soil.
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Make sure to include the instruments or tools used to observe or measure in the investigation.
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Temperature – thermometer in degrees Celsius.
Mass – Balance in grams or kilograms
Volume – Graduated cylinders, graduated beakers and measuring cups in milliliters or liters.
Time – stop watch
Length/Distance – Meter tapes, meter sticks or rulers that measure in centimeters, meters an kilometers
Direction – Compass
Step 4: Planning to Test the Hypothesis
Step 4: Plan to test the hypothesis
• Plan to establish your procedures.
• These are the steps you will follow when conducting or testing your hypothesis.
• The procedures have to be followed in order.
• No steps can be skipped.
• All steps must be exact.
• Remember that other scientists can not compare their results with those of other scientists if the
procedures are not written and followed properly.
• The procedures have to state the specific amounts and types of materials needed in the
investigation.
• Make sure to add any precautions or hazards that may be encountered during the investigation.
• Include safety equipment used before, during and after the investigation is conducted
Step 5: Test the Hypothesis
Step 5: Test the Hypothesis
• Now we are ready to test the hypothesis! (Conduct the investigation)
• Make observations (results) by:
• Collecting data through observations or making measurements in:
• tables
• graphs
• pictures
• drawings
• journal entries
Step 5: Test the Hypothesis
• As you collect data, make sure that each test is repeated over several
trials so that your data can be more dependable and reliable.
• Repeated trials also help to spot mistakes down during an
investigation.
• Repeated trials also help to see if the data is similar between trials
and therefore correct.
• Remember to analyze (look closely) at the data collect and look
for relationships or connections with the data collected.
Step 5: Test the Hypothesis
Temperature of the Water
Trials
30 Degrees Celsius 20 Degrees Celsius 10 Degrees Celsius
Trial 1
0:43
5:18
5:00
Trial 2
0:52
1:22
4:48
Trial 3
0:48
1:41
4:51
Trial 4
0:47
1:32
5:02
Trial 5
0:51
1:35
4:50
IV:
Tempera
ture of
the
Water
DV:
Time it
takes for
the sugar
cubes to
dissolve
DV: Time it
takes for the
sugar cubes
to dissolve
Step 5: Testing the Hypothesis
Sugar Dissolving at Different Temperatures
300
Time in Seconds
Y Axis
318
302
291
288
101
52
TRIAL 1
48
TRIAL 2
51
47
TRIAL 3
TRIAL 4
Temperature of Water
X Axis
Temperature of the Water 30 Degrees Celsius
Temperature of the Water 10 Degrees Celsius
95
92
82
43
290
TRIAL 5
IV: Temperature of the Water
Temperature of the Water 20 Degrees Celsius
Step 5: Testing the Hypothesis
• Write down your observations.
• Example:
• We observed that it took between 47 and 52 seconds (range) for the sugar to dissolve in
the 30 degree temperature water. In the 20 degree water, we noticed that in trial 1, it took
5 minutes and 18 seconds for the sugar to dissolve. It was very different from the results
on the rest of the trials. We must have done something different or wrong in that trial.
Other than that, the range time for the sugar to dissolve was between 1 minute and 22
seconds to 1 minutes 41 seconds. In the 10 degree temperature water, the sugar took
longer to dissolve. The dissolving time was between 4 minutes 48 seconds and 5 minutes 2
seconds.
Step 6: Arrive at a Conclusion
• Arrive at the conclusion by.
• Analyzing data.
• Analyzing means to look at the data closely.
• Interpret the data.
• When data is interpreted, it means to try and figure out what the information is trying to tell
you.
• Try and figure out if there is a connection or relationship between data collected.
• Explain if your hypothesis was correct or incorrect. Remember that if the hypothesis is
incorrect those are still good results because the true answer to your question is now known.
• You can also include in your conclusion what would you do differently the next time you try to
do the experiment to improve.
Step 6: Arrive at a Conclusion
Write down your conclusion:
Example:
As the temperature decreased from 30 to 10 degrees, we inferred (inference) that the
sugar took longer to dissolve. Indirectly, we can tell that if the temperature were to
continue to decrease the dissolving time would be even greater. Due to my data, my
hypothesis was correct! Next time, I will add make sure to follow my procedures
exactly as they are to prevent wrong information.
Essay Assignment
Scientific Method: Potting Soil
We can determine the problem/question and the hypothesis of an experiment by looking
at the differences and similarities between tests. A good problem always has an independent
variable (cause) an dependent variable (effect). It also has a lot of control variables that stay
the same. The DV do not cause results so that my IV can be the only one causing my results.
The _______________________ is the difference between the tests. It is what is changing
between the test and causing my results. The __________, ______________,
____________, and __________________ are staying the same so they must be the controlled
variables. We can tell that the marigolds are _______________________ because of my
independent variable (IV). So the problem/question must be
“Does the _______________ (IV) affect the _________________ (DV) of the
marigolds?”