Units of measurement

1. Jul 18, 2012

geordief

I am talking about length area and volume.

As I reason it out in my own mind area (and volume) is based on length and involves 2 random measurements of length that are combined (with multiplication as the device of convention - could any other function be used to work as well and as usefully?) to give a measurement of area (or Volume with 3 measurements).

Now I understand that this would be seen as reflecting the Classical Physical view of the world and so I am wondering if ,in this limited but easily generalised case , there would be a corresponding approach in non-Classical physics .

In other words , maybe , how do you measure "length" in quantum physics?

If I am talking garbage please tell me !

2. Jul 18, 2012

Staff: Mentor

Quantum physics uses the same concept of space as classical physics. Use a ruler or anything similar, measure the distance.

In special relativity, it is a bit trickier, as lengths are relative. Use a beam of light emitted at one point, measure the time it requires to reach the other point, and you get the distance between the two points in your reference frame. Areas and volumes are the products of lengths.

In general relativity, volume is tricky, too, as space and spacetime can be curved.