I have read several books regarding basic concepts in physics but I'm still puzzled by own lack of knowledge. I shall not give definitions, because I presume we are all familiar with them. I do not have an answer to the following questions:
- I want to know a length in inches. I've measured it with a line in meters and then converted the value to inches. Was this a direct or indirect measurement?
- I want to know how many people are there in a given room. If I do the counting myself - that's a direct measurement. But I've chosen someone else do the counting and report it to me. What kind of measurement will that be?
Can every indirect measurement be converted to a direct one by constructing a machine that does all the steps and gives a one line answer?
3.2. I have a group of people that can measure and calculate everything. This group I can call a tool. If I make them measure something will that constitute as a direct measurement for me?
I want to make a measurement of a derived unit. Is it true that I can never do this with a direct measurement because first I need to measure the basic units and all other units in a chain of mathematical operations?
Thank you for your time