Evaluate Heat Device - Middle School Physical Science
Card 1 of 25
Which type of error causes results to be consistently too high or too low?
Which type of error causes results to be consistently too high or too low?
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Systematic error. Shifts all measurements in the same direction from true value.
Systematic error. Shifts all measurements in the same direction from true value.
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What does agreement with the true or accepted value indicate about a measurement?
What does agreement with the true or accepted value indicate about a measurement?
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High accuracy. Closeness to the true value shows correctness.
High accuracy. Closeness to the true value shows correctness.
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What does a small spread in repeated measurements indicate about the data?
What does a small spread in repeated measurements indicate about the data?
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High precision (consistent results). Close grouping shows measurements are reproducible.
High precision (consistent results). Close grouping shows measurements are reproducible.
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Which term means repeating trials to reduce random error in test results?
Which term means repeating trials to reduce random error in test results?
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Replication (repeated trials). Multiple tests improve reliability by averaging out random variations.
Replication (repeated trials). Multiple tests improve reliability by averaging out random variations.
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Which term means a measurable requirement used to judge a device’s performance?
Which term means a measurable requirement used to judge a device’s performance?
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Design criterion. A specific, measurable goal the device must achieve.
Design criterion. A specific, measurable goal the device must achieve.
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What is the term for a limit a device must stay within (such as cost or size)?
What is the term for a limit a device must stay within (such as cost or size)?
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Constraint. A restriction that sets boundaries for the design.
Constraint. A restriction that sets boundaries for the design.
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What is the best single-number summary of repeated measurements for evaluation?
What is the best single-number summary of repeated measurements for evaluation?
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Mean (average) value. Averaging multiple trials gives the most representative value.
Mean (average) value. Averaging multiple trials gives the most representative value.
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Which type of error causes results to vary unpredictably from trial to trial?
Which type of error causes results to vary unpredictably from trial to trial?
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Random error. Causes scatter around the true value without bias.
Random error. Causes scatter around the true value without bias.
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Choose the correct evaluation: Criterion is mass $\le 200\ \text{g}$; Device mass is $215\ \text{g}$.
Choose the correct evaluation: Criterion is mass $\le 200\ \text{g}$; Device mass is $215\ \text{g}$.
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Constraint violated (does not meet). $215g > 200g$ exceeds the maximum allowed mass.
Constraint violated (does not meet). $215g > 200g$ exceeds the maximum allowed mass.
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Which device better meets the criterion “maximize $\Delta T$” if A: $18^\circ\text{C}$ and B: $21^\circ\text{C}$ under same test?
Which device better meets the criterion “maximize $\Delta T$” if A: $18^\circ\text{C}$ and B: $21^\circ\text{C}$ under same test?
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Device B. $21°C > 18°C$, so B achieves higher temperature rise.
Device B. $21°C > 18°C$, so B achieves higher temperature rise.
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Calculate mean temperature rise for trials $12^\circ\text{C}$, $15^\circ\text{C}$, $13^\circ\text{C}$.
Calculate mean temperature rise for trials $12^\circ\text{C}$, $15^\circ\text{C}$, $13^\circ\text{C}$.
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$13.3^\circ\text{C}$. $(12 + 15 + 13) ÷ 3 = 40 ÷ 3 = 13.3°C$
$13.3^\circ\text{C}$. $(12 + 15 + 13) ÷ 3 = 40 ÷ 3 = 13.3°C$
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Compute $\Delta T$ for $T_i=22^\circ\text{C}$ and $T_f=37^\circ\text{C}$.
Compute $\Delta T$ for $T_i=22^\circ\text{C}$ and $T_f=37^\circ\text{C}$.
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$15^\circ\text{C}$. $37°C - 22°C = 15°C$ using the temperature change formula.
$15^\circ\text{C}$. $37°C - 22°C = 15°C$ using the temperature change formula.
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Which statement correctly decides if the criterion is met: target $\Delta T\ge 15^\circ\text{C}$, measured $\Delta T=14^\circ\text{C}$?
Which statement correctly decides if the criterion is met: target $\Delta T\ge 15^\circ\text{C}$, measured $\Delta T=14^\circ\text{C}$?
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Criterion not met. $14°C < 15°C$, so the minimum requirement isn't reached.
Criterion not met. $14°C < 15°C$, so the minimum requirement isn't reached.
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Identify the dependent variable in a heating test where time is controlled and temperature is measured.
Identify the dependent variable in a heating test where time is controlled and temperature is measured.
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Temperature. The measured variable that responds to changes.
Temperature. The measured variable that responds to changes.
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Which option is the independent variable in a heating test where temperature is recorded every minute?
Which option is the independent variable in a heating test where temperature is recorded every minute?
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Time. The controlled variable that's changed by the experimenter.
Time. The controlled variable that's changed by the experimenter.
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Which graph type best shows how temperature changes over time during a test?
Which graph type best shows how temperature changes over time during a test?
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Line graph of $T$ vs. time. Shows trends and rates of change clearly.
Line graph of $T$ vs. time. Shows trends and rates of change clearly.
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What is the formula for efficiency when comparing useful output to total input?
What is the formula for efficiency when comparing useful output to total input?
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$\text{Efficiency} = \frac{\text{useful output}}{\text{total input}}\times 100%$. Ratio of useful work to energy input, as a percentage.
$\text{Efficiency} = \frac{\text{useful output}}{\text{total input}}\times 100%$. Ratio of useful work to energy input, as a percentage.
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Which formula finds thermal energy gained by a substance during a heating test?
Which formula finds thermal energy gained by a substance during a heating test?
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$Q = mc\Delta T$. Mass times specific heat times temperature change.
$Q = mc\Delta T$. Mass times specific heat times temperature change.
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What is the correct formula for temperature change used in heating tests?
What is the correct formula for temperature change used in heating tests?
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$\Delta T = T_f - T_i$. Final temperature minus initial temperature.
$\Delta T = T_f - T_i$. Final temperature minus initial temperature.
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Identify $\Delta T$: $T_i=22\ ^\circ\text{C}$ and $T_f=37\ ^\circ\text{C}$.
Identify $\Delta T$: $T_i=22\ ^\circ\text{C}$ and $T_f=37\ ^\circ\text{C}$.
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$15\ ^\circ\text{C}$. $37 - 22 = 15$, showing temperature increased by 15 degrees.
$15\ ^\circ\text{C}$. $37 - 22 = 15$, showing temperature increased by 15 degrees.
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What is the meaning of a device meeting a design criterion in a test?
What is the meaning of a device meeting a design criterion in a test?
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It satisfies the specified requirement within the stated limit. The device performs as intended and stays within specified boundaries.
It satisfies the specified requirement within the stated limit. The device performs as intended and stays within specified boundaries.
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What is the difference between a design criterion and a design constraint?
What is the difference between a design criterion and a design constraint?
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Criterion = desired performance; constraint = fixed limit (cost, size, time). Criteria are goals to achieve; constraints are limits that cannot be exceeded.
Criterion = desired performance; constraint = fixed limit (cost, size, time). Criteria are goals to achieve; constraints are limits that cannot be exceeded.
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Which measured value should you compare to a design criterion: raw data or a summary value?
Which measured value should you compare to a design criterion: raw data or a summary value?
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A summary value (mean/median) based on repeated trials. Summary values minimize random variation and provide more reliable comparisons.
A summary value (mean/median) based on repeated trials. Summary values minimize random variation and provide more reliable comparisons.
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What is one reason repeated trials are used when evaluating a device against criteria?
What is one reason repeated trials are used when evaluating a device against criteria?
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To reduce random error and improve reliability. Multiple measurements average out random fluctuations for more accurate results.
To reduce random error and improve reliability. Multiple measurements average out random fluctuations for more accurate results.
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What is the formula for the mean of $n$ trials with results $x_1$ to $x_n$?
What is the formula for the mean of $n$ trials with results $x_1$ to $x_n$?
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$\bar{x}=\frac{x_1+x_2+\cdots+x_n}{n}$. Sum all values and divide by the number of trials to find the average.
$\bar{x}=\frac{x_1+x_2+\cdots+x_n}{n}$. Sum all values and divide by the number of trials to find the average.
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