scientific method. designing an experiment scientists have come up with a method as how to approach...
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Scientific MethodScientific Method
Designing an ExperimentDesigning an Experiment
Scientists have come up with a method as how to approach and perform an experiment.
This method is called the scientific method.
Scientists have come up with a method as how to approach and perform an experiment.
This method is called the scientific method.
Scientific Method StepsScientific Method Steps
Ask a question. Form a Hypothesis. Set up a controlled experiment &
test. Record and analyze results. Draw a conclusion.
Ask a question. Form a Hypothesis. Set up a controlled experiment &
test. Record and analyze results. Draw a conclusion.
Asking a QuestionAsking a Question
A problem must be identified that can be solved by asking a question.
Something is considered a problem if a solution is not obvious. Poor example: What fertilizer is the
best? Good Example:Which fertilizer,
Miracle Grow or VitaGro is best for growing a particular species of roses?
A problem must be identified that can be solved by asking a question.
Something is considered a problem if a solution is not obvious. Poor example: What fertilizer is the
best? Good Example:Which fertilizer,
Miracle Grow or VitaGro is best for growing a particular species of roses?
Form a HypothesisForm a Hypothesis
A hypothesis is a proposed scientific explanation for a set of observations.
Scientists generate hypotheses using prior knowledge, logical inference, and informed imagination.
Basically predict a solution and test it.
A hypothesis is a proposed scientific explanation for a set of observations.
Scientists generate hypotheses using prior knowledge, logical inference, and informed imagination.
Basically predict a solution and test it.
Hypothesis ExamplesHypothesis Examples
Poor Example: I think the fertilizer will help the plants. I think that the roses will grow better with fertilizer
Good Example: If I use Miracle Grow instead of no fertilizer, then the flowers with Miracle Grow will produce more flowers compared to the one without miracle grow.
Poor Example: I think the fertilizer will help the plants. I think that the roses will grow better with fertilizer
Good Example: If I use Miracle Grow instead of no fertilizer, then the flowers with Miracle Grow will produce more flowers compared to the one without miracle grow.
Setting Up a Controlled Experiment
Setting Up a Controlled Experiment
Experiments must contain variables, or factors that can change.
Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged, or controlled, hence the name (controlled experiment).
Experiments must contain variables, or factors that can change.
Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged, or controlled, hence the name (controlled experiment).
Setting Up a Controlled Experiment
Setting Up a Controlled Experiment
Other variables in a controlled experiment include: Independent variables- the variable
that is changed, sometimes called manipulated variable.
Dependent variable- the variable that changes in response to the independent variable. The dependent variable is usually what is measured.
Other variables in a controlled experiment include: Independent variables- the variable
that is changed, sometimes called manipulated variable.
Dependent variable- the variable that changes in response to the independent variable. The dependent variable is usually what is measured.
How to group subjectsHow to group subjects
Experimental groups: subjects who get various amounts of the treatment
Ex: plants getting treatment of miracle gro
Control group: subjects who do not get the treatment
Ex: plants who only receive water and no miracle gro
Experimental groups: subjects who get various amounts of the treatment
Ex: plants getting treatment of miracle gro
Control group: subjects who do not get the treatment
Ex: plants who only receive water and no miracle gro
MaterialsMaterials Make sure that materials are very specific
Poor Example : Roses, soil, water, fertilizer Good Example:
1. 150 red rose plants (same species) each 2 feet tall
2. 150 identical 5 gal buckets with 3 holes in the bottom3. 10 bags of Home Depot brand potting soil (20
lbs.) 4. Miracle Grow fertilizer
5. VitaGrow fertilizer6. Water7. Graduated cylinder to measure water8. Grow lights or green house9. Yard stick
Make sure that materials are very specific Poor Example : Roses, soil, water, fertilizer Good Example:
1. 150 red rose plants (same species) each 2 feet tall
2. 150 identical 5 gal buckets with 3 holes in the bottom3. 10 bags of Home Depot brand potting soil (20
lbs.) 4. Miracle Grow fertilizer
5. VitaGrow fertilizer6. Water7. Graduated cylinder to measure water8. Grow lights or green house9. Yard stick
ProcedureProcedure
Your procedure should be written in such a way that any person using it could get identical results.
Your procedure should be written in such a way that any person using it could get identical results.
Procedure ExamplesProcedure Examples Poor Example: 1.Plant roses, some with fertilizer, some without
2.Water roses3.Set plants under grow light4.Count number of flowers
GoodExample: 1. Fill 150 buckets with potting soil to within one inch of the top. 2. Plant one plant in each bucket so that all of its roots are covered
with potting soil.3. Water each plant with 1 liter of tap water.4. Divide the plants into 3 equal groups of 50 plants each, groups A, B and C
Poor Example: 1.Plant roses, some with fertilizer, some without
2.Water roses3.Set plants under grow light4.Count number of flowers
GoodExample: 1. Fill 150 buckets with potting soil to within one inch of the top. 2. Plant one plant in each bucket so that all of its roots are covered
with potting soil.3. Water each plant with 1 liter of tap water.4. Divide the plants into 3 equal groups of 50 plants each, groups A, B and C
Record & Analyze DataRecord & Analyze Data
Scientists usually keep written records of their observations, or data.
Data may be recorded in two forms: Quantitative data- data expressed in
numbers, obtained by counting or measuring.
Qualitative data- data that is descriptive and involve characteristics that can’t be counted or measured.
Scientists usually keep written records of their observations, or data.
Data may be recorded in two forms: Quantitative data- data expressed in
numbers, obtained by counting or measuring.
Qualitative data- data that is descriptive and involve characteristics that can’t be counted or measured.
DataData
When designing an experiment, you must decide what and how you are going to collect the data. What will you measure. When will you measure it? How will you display the data once it is collected? Be sure to write it specifically in the procedures.
*Typically the independent variable comes first in the data table followed by the dependent variable.
When designing an experiment, you must decide what and how you are going to collect the data. What will you measure. When will you measure it? How will you display the data once it is collected? Be sure to write it specifically in the procedures.
*Typically the independent variable comes first in the data table followed by the dependent variable.
Graphing DataGraphing Data Each graph should have a title that describes what the
graph is about When graphing data, the independent variable always
goes on the X axis, and the dependent variable always goes on the Y axis. .
Each axis of the graph should be marked off in equal units and properly labeled.
Make sure a key is included. In general, use a line graph when both axes are the set
of real numbers. Ex. Time, temperature, height, weight.
In general, use a bar graph when one or both of the axes are not the set of real numbers. Ex. Different kinds of roach spray, people.
Each graph should have a title that describes what the graph is about
When graphing data, the independent variable always goes on the X axis, and the dependent variable always goes on the Y axis. .
Each axis of the graph should be marked off in equal units and properly labeled.
Make sure a key is included. In general, use a line graph when both axes are the set
of real numbers. Ex. Time, temperature, height, weight.
In general, use a bar graph when one or both of the axes are not the set of real numbers. Ex. Different kinds of roach spray, people.
Drawing a ConclusionDrawing a Conclusion
Scientists use the data from an experiment to draw conclusions about the hypothesis. (Either support or reject the hypothesis)
Once a conclusion has been reached, scientist will repeat the experiment to make sure that the results are the same.
Scientists use the data from an experiment to draw conclusions about the hypothesis. (Either support or reject the hypothesis)
Once a conclusion has been reached, scientist will repeat the experiment to make sure that the results are the same.
Writing a ConclusionWriting a Conclusion
Restate your hypothesis. State if your hypothesis was correct or
incorrect. Answer your problem in a complete sentence.
(Always look back at your purpose (problem) to be sure you answer the right question).
PROVE your answer to your problem. Use ACTUAL DATA from your experiment to support your answer. This makes you more credible.
Restate your findings as a concluding thought.
Restate your hypothesis. State if your hypothesis was correct or
incorrect. Answer your problem in a complete sentence.
(Always look back at your purpose (problem) to be sure you answer the right question).
PROVE your answer to your problem. Use ACTUAL DATA from your experiment to support your answer. This makes you more credible.
Restate your findings as a concluding thought.
TheoriesTheories
As evidence from numerous investigations builds up, a particular hypothesis may become so well supported that scientists consider it a theory.
In science, the word theory applies to a well-tested explanation that unifies a broad range of observations.
As evidence from numerous investigations builds up, a particular hypothesis may become so well supported that scientists consider it a theory.
In science, the word theory applies to a well-tested explanation that unifies a broad range of observations.
