A Is it correct to state that all measurements count photons?

[Chiara]

A text I read some weeks ago claimed that all measurements count photons. Indeed, even a thermometer requires light to be read off, and also a balance.

Is there a type of measurement or a measurement device that does not count photons?

 

[Algr]

Measurements of weight or sound come to mind.

 

[Dale]

A text I read some weeks ago claimed that all measurements count photons. Indeed, even a thermometer requires light to be read off, and also a balance.

Is there a type of measurement or a measurement device that does not count photons?

There is a very big difference between using photons and counting photons.

 

[PeterDonis]

A text I read

What text? Please give a specific reference.

 

[Chiara]

There is a very big difference between using photons and counting photons.

Indeed. But is there a really precise measurement device that does not count photons?

 

[PeterDonis]

is there a really precise measurement device that does not count photons?

Almost all measuring devices do not count photons.

For example, you mention reading a thermometer, which requires light to see its reading. But the process of you seeing the light that tells you what the thermometer reads does not involve counting photons.

In short, whatever source you read seems highly questionable. But we can't say anything more about that unless and until you tell us specifically what that source is.

 

[Dale]

Indeed. But is there a really precise measurement device that does not count photons?

Most do not. Even measurements based on quantum phenomena, such as an atomic clock.

I agree that it would be good to know the source of this claim