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The Scientific Method
The Steps to Success
The Scientific Method
What is the scientific method? It is a process that is used to find answers to questions about the world around us.
Is there only one “scientific method”?
No, there are several versions of the
scientific method.
Some versions have more steps,
while others may have only a few.
However, they all begin with the
identification of a problem or a
question to be answered based on
observations of the world around us.
They provide an organized method for conducting and analyzing an experiment.
What is a hypothesis?
It is an educated
guess based on
observations and
your knowledge
of the topic.
You state it as a
possible answer
to a question.
Stated in the “If….., then….” format
Example: IF I water three plants with different sodas, THEN the plant that receives Sprite will grow the tallest.
What is data? It is information gathered during an experiment.
It is organized into a data table and displayed visually as a graph.
Graphs BAR GRAPHS: can be used to
show how something changes over time or to compare items. have an x-axis (horizontal)
and a y-axis (vertical) the x-axis has time period or
what is being measured the y-axis has numbers for
the amount of stuff being measured.
good when you're plotting data that spans many years (or days, weeks...), has really big changes from year to year (or day to day...), or when you are comparing things.
LINE GRAPHS: can be used to show how something changes over time
x-axis has numbers for the time period
y-axis has numbers for what is being measured.
can be used when you're plotting data that has peaks (ups) and valleys (downs), or that was collected in a short time period.
Used for two sets of numerical data (ex: time and temp)
1. Choose a problem: State the problem as a question.
2. Research your problem: Read, get advice, and make observations.
3. Develop a hypothesis: Make a prediction about what will happen.
4. Design an experiment: Plan how you will test your hypothesis.
Steps of the Scientific Method
5. Test your hypothesis: Conduct the experiment and record the data.
6. Organize your data: Create a chart or graph of your data.
7. Draw conclusions: Analyze your data and summarize your findings.
Identifying Variables
Independent VariablesDependent VariablesControlled Variables (Constants)
Independent Variable – something that is changed by the scientistWhat is testedWhat is manipulated (changed)
3 Kinds of Variables
Dependent Variable – something that might be affected by the change in the independent variableWhat is observedWhat is measuredThe data collected during the
investigation “the numbers”Example: how tall the plant grew, how
far the paper airplane flew
Example:
Controlled Variable – a variable that is not changedAlso called CONSTANTSAllow for a “fair test”Everything in the experiment except for the IV should be kept constant
Give a detailed explanation of how you will conduct the experiment to test your hypothesis
Be clear about the variables (elements you change) versus your constants (elements that do not change)
A control is the group that you use as a comparison to see if change has occurred. Example: In a medicine study, the group
of people who don’t get the medicine are the control group
Procedure
Be very specific about how you will measure results to prove or disprove your hypothesis. You should include a regular timetable for measuring results or observing the projects (such as every hour, every day, every week)
Conclusion: your results or findings based on data collected during the experiment
Answer your problem/purpose statement What does it all add up to? What is the
value of your project? What further study do you recommend
given the results of your experiment? What would be the next question to ask?
If you repeat this project, what would you change?
Conclusion
For Example:
Students of different ages were given a jigsaw puzzle to put together. The scientist wanted to see if the students’ ages affected how long it took to put the puzzle together.
Independent Variable (IV):Ages of the studentsDifferent ages were tested by the scientist
Dependent Variable (DV):The time it took to put the puzzle together
The time was observed and measured by the scientist
Identify the Variables in this Experiment:
(1) Same puzzleAll of the participants were tested
with the same puzzle. It would not have been a fair test if
some had an easy 30 piece puzzle and some had a harder 500 piece puzzle.
Other constants: (2) same location, (3) same stopwatch, (4) same person timing the experiment
What were the constants?
An investigation was done with an electromagnetic system made from a battery and wire wrapped around a nail. Different sizes of nails were used. The number of paper clips the electromagnet could pick up was measured.
Another Example:
IV: Sizes of nailsThese were changed by the scientist
DV: Number of paper clips picked upThe number of paper clips observed and counted (measured)
Constants: Battery, wire, type of nailNone of these items were changed
What are the Variables?
Let’s Practice!
If I use a heavier bowling ball, then the ball will travel faster down the lane.
IV: weight of bowling ballDV: speed it traveled down lane
2) If I use different brands of paper towels, then Bounty will absorb more water per minute than Sparkle or Quilted.
IV: brand of paper towelDV: amount of water
absorbed per minute
3) If I put 3 spider plants in different locations, then the plant in the sunlight will grow taller in a one-week period than the plants in the closet and basement.
IV: location of the plantsDV: height of plants