Glad you found our videos. If you watch the entire series of physics videos (which is a huge task since there are a lot of videos), you WILL understand physics very well. 🙂

That is a good question. It turns out the understanding and applying uncertainties to any lab experiment or any type of research and development is VERY important. Considerations going into determining uncertainty: 1) Accuracy of the tool. 2) Conditions of the tool, how easy is it to read the numbers. 3) Affect of temperature (a ruler will expand when it is warmer) 4) The conditions under which the measurement was made 5) how easy was it to apply the tool (How close could you get the tool 6) Was the tool calibrated? 7) How experienced was the person using the tool. 8) What were the lighting conditions. etc. Each of those answers will affect the size of the uncertainty. +/- simply implies that you could have over or underestimated the measurement.

i see thanks a lot appreciate your work

Glad it did. 🙂

Precise, means that consecutive measurements give you nearly the same value. Accurate means that the measurements are very close to the real value. They are not related. They can be precise and very accurat and they can be precise and very inaccurate.

That is often what is taught in the classroom, but that is not always correct. There are many factors to take into account: the person's eye sight, the person's experience, the person's skill level, the lighting conditions, the accuracy of the apparatus, the temperature (since the length of the istrument will change with temperature, calibration, etc.

@@MichelvanBiezen sir, Is there a general rule for this? I have seen from a certain source that the uncertainty is 20% of the least count while other it is half of the least count. Is this true sir?

Mr. van Biezen will not see comment threads older than a couple of days. If you want him to see your "new" comment, you have to start a new comment thread. -Mr. van Biezen's Wife

Kamyar. I found the videos to be very well done and very informative. The pace of explanation is also good and the illustrations are fun. The big question we have to answer when we make videos is: 1) What is the purpose, what do we expect the viewer to get out of the videos? 2) Why would anyone want to watch our videos? Are they entertaining? Just informative? Are they practical? Sometimes the comments when we get them helps us understand what the viewer likes (or doesn't like) about them and we can then adjust. When we started our channel 10 years ago we were excited when one of our videos hit 100 views. We had no idea the channel would grow to what it is today. I think the key to our channel is that it helps students understand difficult concepts usually not well explained by their professors and watching our videos helps them do the homework and do better on their exams - which answers the question: "why would anyone want to watch these videos?" Although purely entertaining videos tend to be more popular.

@Michel van Biezen Dear Michel, actually a full training, rather than teaching, needs educational consulting, pdf resources and problem solving based on demand, and also quizzes. In our channels, we just can do the first part. But I think a professional work like yours, could be a real guide for all the audiences, both the beginners and high level students. Still we need some more idea shaping to provide better service for our audiences. Thank you for your attention.

@Michel van Biezen Your videos are of course informative but majority of the audiences for the first time watch our videos for a supplementary learning. If they subscribe, they may continue as continuing learners. We can make the videos in sequence with suitable titles ( like yours) to help them get full courses. How Practical they are, we should ask them.

All the best on you venture. It sounds promising.

You have been watching a lot of videos and different topics. Glad you are enjoying them.

Whenever something is measured, during an observation or an experiment, we are never sure that the measurement is 100% correct. When you step on a scale and the scale reads 67kg, how do you know that is correct. The scale is not perfect, it may not have been calibrated, the mechanism may be defective, so you conclude that the mass is between 65 kg and 69 kg. Therefore the uncertainty is +/- 2 kg.

@@MichelvanBiezen thank you...

@@MichelvanBiezen i heard from someone said that for ruler you can't go 0.05cm or 0.5mm more...does it apply to other units of measurements as well? like kg, g, m, km?

You're welcome!