Improve Device Design - Middle School Physical Science
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What is the independent variable in a device test where you change only the mass added?
What is the independent variable in a device test where you change only the mass added?
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The mass added to the device. The variable you deliberately change to test its effect.
The mass added to the device. The variable you deliberately change to test its effect.
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What is the dependent variable in a device test where you measure stopping distance?
What is the dependent variable in a device test where you measure stopping distance?
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The stopping distance measured. The variable you measure to see how it responds to changes.
The stopping distance measured. The variable you measure to see how it responds to changes.
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What is a controlled variable in a test of paper airplane flight time?
What is a controlled variable in a test of paper airplane flight time?
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A factor kept constant, such as paper type. Variables held constant to ensure only one factor affects results.
A factor kept constant, such as paper type. Variables held constant to ensure only one factor affects results.
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Find the percent improvement from $40,\text{cm}$ to $30,\text{cm}$ stopping distance.
Find the percent improvement from $40,\text{cm}$ to $30,\text{cm}$ stopping distance.
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$25%$ improvement. $\frac{40-30}{40} \times 100% = \frac{10}{40} \times 100% = 25%$
$25%$ improvement. $\frac{40-30}{40} \times 100% = \frac{10}{40} \times 100% = 25%$
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What should you record in a test log to make device optimization decisions evidence-based?
What should you record in a test log to make device optimization decisions evidence-based?
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Setup, variables, trials, measurements, and observations. Complete documentation enables data-driven design decisions.
Setup, variables, trials, measurements, and observations. Complete documentation enables data-driven design decisions.
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State the formula for percent change from old value $O$ to new value $N$.
State the formula for percent change from old value $O$ to new value $N$.
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$%\text{ change}=\frac{N-O}{O}\times 100%$. Subtract old from new, divide by old, multiply by 100.
$%\text{ change}=\frac{N-O}{O}\times 100%$. Subtract old from new, divide by old, multiply by 100.
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Identify the median of these five test results: $4$, $5$, $5$, $6$, $20$.
Identify the median of these five test results: $4$, $5$, $5$, $6$, $20$.
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$5$. Middle value when arranged in order: $4, 5, 5, 6, 20$.
$5$. Middle value when arranged in order: $4, 5, 5, 6, 20$.
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Find the mean speed if three trials give $2.0,\text{m/s}$, $2.4,\text{m/s}$, $2.6,\text{m/s}$.
Find the mean speed if three trials give $2.0,\text{m/s}$, $2.4,\text{m/s}$, $2.6,\text{m/s}$.
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$2.33,\text{m/s}$. $(2.0 + 2.4 + 2.6) ÷ 3 = 7.0 ÷ 3 = 2.33$
$2.33,\text{m/s}$. $(2.0 + 2.4 + 2.6) ÷ 3 = 7.0 ÷ 3 = 2.33$
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Which graph type is best for showing how device performance changes over time or trials?
Which graph type is best for showing how device performance changes over time or trials?
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A line graph. Line graphs clearly display trends and changes across trials.
A line graph. Line graphs clearly display trends and changes across trials.
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What does an outlier in device test data most likely indicate?
What does an outlier in device test data most likely indicate?
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A mistake or unusual condition in a trial. Outliers suggest experimental errors or abnormal test conditions.
A mistake or unusual condition in a trial. Outliers suggest experimental errors or abnormal test conditions.
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What does it mean if test results are precise but not accurate?
What does it mean if test results are precise but not accurate?
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Values are consistent but far from the true value. Measurements cluster together but miss the target value.
Values are consistent but far from the true value. Measurements cluster together but miss the target value.
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What is the best reason to run multiple trials for the same device setup?
What is the best reason to run multiple trials for the same device setup?
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To reduce random error and improve reliability. Multiple trials average out random variations for consistent results.
To reduce random error and improve reliability. Multiple trials average out random variations for consistent results.
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What is the mean (average) of trial results used for when comparing device versions?
What is the mean (average) of trial results used for when comparing device versions?
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A single representative value for performance. Averaging trials gives one number to fairly compare designs.
A single representative value for performance. Averaging trials gives one number to fairly compare designs.
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State the formula for the mean of three trials $x_1$, $x_2$, and $x_3$.
State the formula for the mean of three trials $x_1$, $x_2$, and $x_3$.
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$\text{mean}=\frac{x_1+x_2+x_3}{3}$. Sum all values and divide by the number of trials.
$\text{mean}=\frac{x_1+x_2+x_3}{3}$. Sum all values and divide by the number of trials.
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What is the purpose of using test results when improving a device design?
What is the purpose of using test results when improving a device design?
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To identify weaknesses and guide specific design changes. Test data reveals what needs improvement for targeted modifications.
To identify weaknesses and guide specific design changes. Test data reveals what needs improvement for targeted modifications.
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Which type of error is suggested by results that are consistently too high each trial?
Which type of error is suggested by results that are consistently too high each trial?
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Systematic error. Consistent bias indicates a calibration or method issue.
Systematic error. Consistent bias indicates a calibration or method issue.
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What does high accuracy mean for a device performance measurement?
What does high accuracy mean for a device performance measurement?
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The result is close to the accepted or true value. Accurate measurements match the expected value.
The result is close to the accepted or true value. Accurate measurements match the expected value.
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Identify the best measure of a device's typical performance from repeated trials.
Identify the best measure of a device's typical performance from repeated trials.
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The mean (average) of the trial results. Averaging reduces the impact of random variations.
The mean (average) of the trial results. Averaging reduces the impact of random variations.
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What does high precision mean when you repeat a device test several times?
What does high precision mean when you repeat a device test several times?
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Repeated results are close to each other (low spread). Precise measurements cluster tightly together.
Repeated results are close to each other (low spread). Precise measurements cluster tightly together.
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What is the formula for the mean (average) of $n$ measurements?
What is the formula for the mean (average) of $n$ measurements?
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$\bar{x}=\frac{x_1+x_2+\cdots+x_n}{n}$. Sum all values and divide by the count.
$\bar{x}=\frac{x_1+x_2+\cdots+x_n}{n}$. Sum all values and divide by the count.
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What is the formula for percent error when comparing to an accepted value?
What is the formula for percent error when comparing to an accepted value?
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$\frac{|\text{measured}-\text{accepted}|}{\text{accepted}}\times 100%$. Absolute difference divided by accepted value, as percentage.
$\frac{|\text{measured}-\text{accepted}|}{\text{accepted}}\times 100%$. Absolute difference divided by accepted value, as percentage.
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What is the purpose of repeating trials when testing a device?
What is the purpose of repeating trials when testing a device?
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To reduce random error and increase reliability. Averaging multiple trials minimizes random variations.
To reduce random error and increase reliability. Averaging multiple trials minimizes random variations.
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What is a trial in an engineering test procedure?
What is a trial in an engineering test procedure?
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One complete run of the test under specific conditions. Multiple trials help identify consistent patterns.
One complete run of the test under specific conditions. Multiple trials help identify consistent patterns.
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What is a controlled variable in a device test?
What is a controlled variable in a device test?
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A condition kept the same in every trial. Controls ensure only the independent variable affects results.
A condition kept the same in every trial. Controls ensure only the independent variable affects results.
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What is the independent variable in a device optimization test?
What is the independent variable in a device optimization test?
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The factor you intentionally change between trials. This variable causes changes in the dependent variable.
The factor you intentionally change between trials. This variable causes changes in the dependent variable.
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