Experimental Design

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# Experimental Design - PowerPoint PPT Presentation

Experimental Design. ????????????????????????????. What’s the question. Hypothesis. If-then statement If part - shows a relationship (can be cause-effect) Then part – is your prediction

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## PowerPoint Slideshow about ' Experimental Design' - trenton-dempsey

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Presentation Transcript
????????????????????????????
• What’s the question
Hypothesis
• If-then statement
• If part - shows a relationship (can be cause-effect)
• Then part – is your prediction
• If the texture/pattern of a paper towel affects the rate at which it picks up water, then a paper towel with more indentations and therefore surface area will pick up water the fastest.
An experiment needs:
• To test only one variable
• All other variables are constant
• Example: To test which fertilizer is the most effective, the variable is the type of fertilizer.
• What should you keep constant?
An experiment needs:
• Control Group – Where all factors are standard or kept the same. This is what you will compare your experimental group to
• Experimental (Variable) Group – All conditions are kept constant EXCEPT for the variable
Experiment

A

B

D

C

What group is the control group?

An experiment needs:
• Independent (Manipulated) Variable – The factor that you deliberately change (fertilizer)
• Dependent (Responding) Variable – The factor that changes in response to the manipulated variable (plant growth)
Experiment

A

B

D

C

What group is the control group?

An experiment needs:
• Data- the more trials or the larger the sample size, the more reliable your data will be.
• Quantitative- numerical data
• Qualitative- descriptive data
• Your data will need to be organized so that the result is clear.
Data Collections

Beaker Test Tube Pipette

Which is the most precise?

Accuracy - the ability of a measurement to match the actual quantity being measured
• The true value
• Precision – the ability of a measurement to be consistently repeated
An experiment needs…
• Conclusions- your experimental results need to be communicated to
• For example: Fertilizer A will be the most effective in aiding plant growth because it contains the most nutrients.
• Theory- after many hypotheses have been tested and have not been proven incorrect, the hypotheses will become a part of a theory.
Theory-
• How have you heard this word used in “the real world”?
• Why is it important that we know the scientific definition?