実験プログラム
国際バカロレア · IB Diploma · Chemistry · SL トピック 22 4:07 英語ナレーション・英語＋中文字幕 burning-in
章
Transcript
A line passing near every data point is useful, but its gradient can still be uncertain.
穿过每个数据点附近的直线很有用，但其斜率仍可能存在不确定性。
A graph is evidence for a model within the measurement range.
在测量范围内，该图可作为模型的证据。
Random variation makes repeated readings differ.
随机变异导致重复读数不同。
Systematic error shifts results consistently.
系统误差使结果发生一致偏移。
Absolute uncertainty has the measured unit.
绝对不确定度具有测量单位。
Relative or percentage uncertainty compares uncertainty with the measured value.
相对或百分比不确定度将不确定度与测量值进行比较。
Uncertainty is a quantified limitation on a measured result.
不确定度是对测量结果的量化限制。
Systematic error is a consistent measurement bias.
系统误差是一种一致的测量偏差。
For a product or quotient, adding fractional uncertainties is a common maximum uncertainty approximation.
对于乘积或商，将相对不确定度相加是一种常见的最大不确定度近似。
For a difference, add absolute uncertainties.
对于差值，则应相加绝对不确定度。
A nonzero intercept can reveal an offset or an incomplete model.
非零截距可能表明存在偏移或模型不完整。
In the lab: Show units on axes and choose a sensible scale.
在实验室中，坐标轴上需标注单位并选择合适的刻度。
Plot uncertainty bars where justified, draw a best-fit line rather than joining every point, and estimate steepest and shallowest plausible gradients when the course method calls for them.
在合理处绘制不确定度误差棒，画最佳拟合线而非连接每个数据点；当课程方法要求时，估算最陡和最缓的合理斜率。
Known: length equals fifty point zero millimetres with uncertainty one point zero millimetres.
已知：长度为50.0毫米，不确定度为1.0毫米。
Percentage uncertainty equals absolute uncertainty divided by value, times one hundred.
百分比不确定度等于绝对不确定度除以数值，再乘以100。
This is one point zero divided by fifty point zero, times one hundred, which equals two point zero percent.
即1.0除以50.0，乘以100，结果为2.0%。
For a quotient of two independently measured quantities with maximum percentage uncertainties two percent and three percent, the summed maximum estimate is five percent.
对于两个独立测量量的商，若其最大百分比不确定度分别为2%和3%，则相加得到的最大估计值为5%。
Your turn: A 40 cm reading has an absolute uncertainty of 1 cm.
轮到你了。 一个 40 厘米的读数，其绝对不确定度为 1 厘米。
Find percentage uncertainty.
求百分比不确定度。
Pause the video and work it out.
请暂停视频，自己算一算。
Check: 1 centimetre divided by 40 centimetres is 2.5 percent.
核对：1 厘米 ÷ 40 厘米 = 2.5%。
Repeating readings reduces random uncertainty in a mean, but does not automatically remove a zero error.
重复读数可降低平均值中的随机不确定度，但并不能自动消除零点误差。
Do not quote more decimal places than your measurement can support.
不要给出超出测量支持精度的小数位数。
Not true: Repeating a measurement always removes a calibration offset.
这种说法不正确。 重复测量并不总能消除校准偏差。
Repeating and averaging reduces RANDOM scatter in the mean.
重复并取平均值只能减小均值中的随机离散度。
A calibration offset shifts every reading identically, so repeats land on the same wrong value; only recalibration removes it.
校准偏差会使每次读数产生相同的偏移，因此重复测量仍落在同一个错误数值上。 只有重新校准才能消除它。
Random variation makes repeated readings differ.
随机变异会导致重复读数不同。
For a product or quotient, adding fractional uncertainties is a common maximum uncertainty approximation.
对于乘积或商，将相对不确定度相加是一种常见的最大不确定度近似方法。
Watch for: repeating readings reduces random uncertainty in a mean but does not automatically remove a zero error.
请注意：重复读数可以降低平均值中的随机不确定度，但并不能自动消除零点误差。
A reading is twenty centimetres and the absolute uncertainty is one centimetre.
读数为20厘米，绝对不确定度为1厘米。
Find the percentage uncertainty.
求百分比不确定度。
Repeating the measurement does not remove a calibration offset.
重复测量无法消除校准偏差。
The result is a percentage uncertainty of 5 percent.
结果是百分比不确定度为5%。
Each point has an uncertainty bar, and the line passes through every bar.
每个点都有不确定度误差棒，直线穿过所有误差棒。
The data are consistent with a straight-line relationship.
数据与直线关系一致。
Lengths are 50 plus or minus 1 millimetres and 20 plus or minus 1 millimetres.
长度分别为 (50±1) mm 和 (20±1) mm。
Estimate the quotient and its maximum percentage uncertainty, distinguishing this convention from independent standard-uncertainty propagation.
请估算商及其最大百分比不确定度，并区分此惯例与独立标准不确定度传播。
The quotient is 2.5.
商为 2.5。
The maximum estimate is 2 percent plus 5 percent, which is 7 percent, an absolute uncertainty of about 0.18.
最大不确定度估计为 2% 加 5%，即 7%，绝对不确定度约为 0.18。
Independent standard uncertainties instead combine in quadrature, to about 5.39 percent; declare which convention the data support.
若各不确定度为独立的标准不确定度，则应按平方和开方合成，约为 5.39%；要说明数据适用哪一种约定。
Pause and check yourself. Explain each point on screen in your own words, then change one number in the last example and say which assumption must still hold.
暂停一下，自我检查：用自己的话解释屏幕上的每个要点，再改动最后一个例子中的一个数字，说明哪个假设仍然必须成立。