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25 Cards in this Set
- Front
- Back
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An aspect of an experiment that changes during the course of an experiment. |
Experimental variable |
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The variable or part of the experiment to which all others will be compared. |
Control of the experiment |
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Experiments in which neither the participants nor the people analyzing the results know who is in the control group. |
Double-blind experiment |
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An experiment variable is good when you are using it to _____ something from the experiment. |
learn |
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An experimental variable should be reduced or eliminated when it _____ the results of the experiment but you do not learn anything from it. |
affects |
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In the boat experiment, what was the good experimental variable from which you learned? |
the types of "motor" used in the different "boats." |
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In the boat experiment, what are some experimental variables you needed to reduce or eliminate? |
The timing of placing the boats into the water. The differences in the boats. Size differences between the boat motors. Air drafts in the room. |
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In the experiment that tests the effectiveness of different laundry detergents, what is the control for the experiment? |
The shirt washed with no detergent.
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In the experiment that tests the effectiveness of different laundry detergents, what is the experimental variable from which you learn something about the experiment? |
The type of detergent used. |
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In the experiment that tests the effectiveness of different laundry detergents, what are the unwanted experimental variables? |
(1) The washer used. (2) The water temperature from washer to washer can differ. (3) The shirts can differ. (4) It's virtually impossible to stain shirts evenly. |
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How can you reduce or eliminate the experimental variable involving the washer used? |
Make sure the same brand/model is used for each washer.
Make sure each washer used is new.
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How can you reduce or eliminate the experimental variable involving washer water temperature? |
You can monitor the temperature of the water in the washer drum with a thermometer, recording temperature during the wash cycles.
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How can you reduce or eliminate the experimental variable involving the shirts used? |
You can ensure all shirts are from the same manufacturer, style, and fabric. |
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How can you reduce or eliminate the experimental variable involving the amount of stain? |
You could apply the stain with a robotic arm calibrated to apply the same pressure for the same amount of time each time.
You could examine each stain carefully to ensure all stains are equivalent.
You could mark a controlled area and only examine the stain in that spot. |
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Are the data collected in the laundry stain experiment objective or subjective? |
Subjective. Each person's definition of "dirty" differs. The shirts are examined by eye. The vision of examiner's may differ. |
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Why does a carefully placed needle float on water, even though the needle is denser than water? |
Because of the water's surface tension. |
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What does soap do to the surface tension of water? |
Soap reduces the surface tension of water. |
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If a student tries to float a needle on water with difficulty, then floats a needle of another type of liquid with ease, what does this say about the second liquid? |
It has a greater surface tension than water. |
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How should a person design the fat-free potato chip experiment? |
(1) Give 1/2 the volunteers the fat-free potato chip brand and the other half a long-term potato chip brand.
(2) Volunteers can log how they feel or you can personally observe them for a specified time.
(3) If fat-free = more cramps, allegation could be true. |
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What is the control group of the fat-free potato chip experiment? |
The group that eats the long-term, problem-free potato chip brand. |
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Should the potato chip experiment be: A. single-blind B. double-blind, or C. neither |
B. double-blind Knowing you got the fat-free chip, you might imagine stomach cramps.
Since how volunteers feel is subjective, the data is qualitative not quantitative. If data analysts are also "blind," they don't introduce more subjectivity.
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Should the herb/concentration experiment be: A. single-blind B. double-blind, or C. neither |
A. single blind
The students shouldn't know if they got the herbal pill or a sugar pill.
Since the data is objective, the data analyst doesn't have to be blind, though double-blind avoids the appearance of dishonesty. |
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Should the cornfield/herbicide experiment be: A. single-blind B. double-blind, or C. neither |
C. neither
For single-blind, the corn "not knowing" is irrelevant.
For double-blind, the farmer not knowing is also irrelevant since the data--corn production--is objective. Unless the farmer has a vested interest in one of the herbicide companies! |
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Should the homeschool/public schooled play comparison be: A. single-blind B. double-blind, or C. neither |
B. double-blind
Students should not know whether they're in the control group or not.
Researcher's must also not know who is in the control group or not. |
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Should the diet pill experiment be: A. single-blind B. double-blind, or C. neither |
A. single blind
Subjects shouldn't know if they've taken a diet pill or a placebo.
Since the data--weight--is objective, the researcher doesn't have to be blind. But "blind" always eliminates the appearance of impropriety. |
