Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always...
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Transcript of Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always...
![Page 1: Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always some degree of uncertainty in your result. A person.](https://reader036.fdocuments.in/reader036/viewer/2022082917/5514ddc1550346935c8b54b8/html5/thumbnails/1.jpg)
Uncertainties in Measurement
![Page 2: Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always some degree of uncertainty in your result. A person.](https://reader036.fdocuments.in/reader036/viewer/2022082917/5514ddc1550346935c8b54b8/html5/thumbnails/2.jpg)
What is uncertainty
• When you are making a measurement, there is always some degree of uncertainty in your result.
• A person who says they are 1.94 m tall is unlikely to be exactly that height and could be up to half a centimetre taller or smaller.
• We say their height is 1.940 ± 0.005 m.
• The uncertainty is ± 0.005 m.
![Page 3: Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always some degree of uncertainty in your result. A person.](https://reader036.fdocuments.in/reader036/viewer/2022082917/5514ddc1550346935c8b54b8/html5/thumbnails/3.jpg)
What causes uncertainty ?
• There are three causes of uncertainty we need to know about in Higher Physics.
• Random uncertainty
• Systematic uncertainty
• Reading uncertainty
![Page 4: Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always some degree of uncertainty in your result. A person.](https://reader036.fdocuments.in/reader036/viewer/2022082917/5514ddc1550346935c8b54b8/html5/thumbnails/4.jpg)
More about Random Uncertainty
• This is caused by random and unpredictable changes in the experimental conditions.
• These are equally likely to make the results of the measurements too big or too small.
• Repeated measurements can help reduce the effects of random uncertainty.
![Page 5: Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always some degree of uncertainty in your result. A person.](https://reader036.fdocuments.in/reader036/viewer/2022082917/5514ddc1550346935c8b54b8/html5/thumbnails/5.jpg)
More about Systematic Uncertainty
• Systematic effects are caused by faulty equipment or faulty experimental technique.
• Systematic effects have occurred when the results of the measurements are all too big or too small.
• A graph which is a straight line but does not go through the origin as expected is likely to be due to systematic effects.
![Page 6: Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always some degree of uncertainty in your result. A person.](https://reader036.fdocuments.in/reader036/viewer/2022082917/5514ddc1550346935c8b54b8/html5/thumbnails/6.jpg)
More about Reading Uncertainty
• This is a measure of how well a scale can be read.
• For an analogue scale, the uncertainty is ± half of the smallest scale division.
• For a digital scale, the uncertainty is ± 1 in the least significant digit.
![Page 7: Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always some degree of uncertainty in your result. A person.](https://reader036.fdocuments.in/reader036/viewer/2022082917/5514ddc1550346935c8b54b8/html5/thumbnails/7.jpg)
Example of an analogue scale
The voltmeter on the left has an analogue scale. The smallest scale division is 1 volt. The uncertainty from reading this scale is ± 0.5 volts.
![Page 8: Uncertainties in Measurement. What is uncertainty When you are making a measurement, there is always some degree of uncertainty in your result. A person.](https://reader036.fdocuments.in/reader036/viewer/2022082917/5514ddc1550346935c8b54b8/html5/thumbnails/8.jpg)
Example of a digital scale
The voltmeter on the left has a digital scale. The least significant digit is the 8. The uncertainty from reading this scale is ± 0.1 volts.