I was so confused after doing uncertainty in class but this video cleared it all up. Many thanks, just started A level physics and I think I'l be back to this channel a lot over the next 2 years...
Hey, thanks for all the videos you make on physics, it really helps me consolidate my knowledge coming up to the AS exams, and I also like your sense of humour. It always makes me chuckle hearing you complain about how rubbish a past paper question is or whatnot
If you still need help with A Level Physics, you should check out Alt Academy, we have a TON of resources, including video lessons, revision guides, 24/7 academic support, handwritten past paper solutions with explanations on each step, and we even have our instructors sit live every night and solve a timed past paper, explaining why they're taking each step.
Some digital device reading can have zero errors if they aren't zeroed(calibrated). Eg. There's a zero button in digital scales, but if you press it when there's a weight on it, it will use the weight as the starting point of the reading instead of 0, hence zero error.
This is the syllabus which you need for the exams. However it is obviously dodgy and not what professional physicists do. Like the prof suggests, That first thermometer example would be recorded as 21.4 with a visual reading uncertainty of +/- 0.2 or similar. We humans are not blind and can easily read between the lines and we can appreciate our visual error here is about maybe a tenth or 2 tenths of a division. In fact stating 21 +/- 0.5 would be very dodgy as just a tiny misread could so easily have given 22 +/- 0.5. Also a good scientist will look at the box to find the manufacturers estimated confidence in readings, and then possibly add an extra 0.1 or 0.2 to his uncertainty. It is unfortunate that the exam boards have tried to oversimplify things for the sake of a simple syllabus and by doing this they are preventing students from thinking clearly for themselves. They are therefore presenting science like english literature like something to be memorised. The exam boards need to get more feedback from top class physicists who are not nervous to give their opinions.
So when matching precision of our calculation to the recorded values, do we use the least precise sig fig or dp? I hope that made sense... Also, thank you for saving my life with this video!
In the Assumed Uncertainty part of the video. I believe you gave the Resolution. For example you stated the voltage as 5.27V the resolution of the reading is the smallest possible value which is 0.01V. The uncertainty will be 0.01V/2 half the resolution. Correct me if I’m wrong sir? Is this something unique to Edexcel A level exam board since this is what the MS I have seen are doing.🤔
@@WillWright77 welcome to the club my friend. just know the majority of students have done little work compared to this good students so we should do well
I feel like there are discrepancies if you don't know the insruments precision why is the uncertainty + or - 1 x lowest sig.fig and not 0.5 x lowest sig.fig since the measurement might be calibrated
we got this stuff for bridging work so I haven't even started physics a level and they've given us this with no help -_- Thanks a ton dude u helped me understand. I would've been a wreck :D
I believe the initial example is wrong; the resolution of the scale markings provide a guide, not a hard limit, to the precision of the reading/measurement available from a given metrological instrument. For example, if I had a metre stick with no markings, I could still take a reading to within half a metre (or a third or a quarter). Similar applies to the example in the video of a reading which can be seen to fall closer to 21.5 than either 20.0 or 21.0. So a reading of 21.5 degrees +/_ 0.5 degree is reasonable and correct (not 21 +/_ 0.5). No? Just feedback and comment, thanks for the vids, they are awesome.
My undergrad professor very loosely explained uncertainty but still expected us to do it. He didn't care if we did it right he just wanted us thinking about it. Because of that I never learned how to do this properly
Does the fact that Uncertainty for readings is half the resolution,and for measurements it is the resolution,hold up even in higher studies or just till the A'levels?
I got sick and had to to to the hospital so I skipped my physics class once. I miss out on this. it doesn't end there, tommorow there's a test about this uncertainty. Thanks really helped me to get the base
At 8:55 you said that the uncertainty should have the same number of decimal places as the measurement, while in the example of measuring with a termomether (2:05) you wrote an uncertainity of 0.5 when the reading on the instrument was an integer number. Why is that so?
It is my understanding that the first measurement for the thermometer can be written as 21.4 degree Celsius, because you know 21 for certain and then estimate the next place value (uncertain value). You are allowed to do this when the tool counts by 100, 10, 1, 0.1, 0.01, etc. This will then lead to the nominal and uncertainty having the same number of decimal places which is another rule? Please advise.