The definition I'm using for interval would be that the values should have equal differences and there zero point is chosen somewhat arbitrary (e.g. 0 on the scale does not mean the absence of the underlying property that is being measured).

This means that any non-linear scale cannot be interval since it would violate the 'equal intervals' part. IQ is sometimes used as an example of interval, but that actually does not have equal intervals.

I've tried googling for other examples of an interval scale but couldn't find any (at least not on the first five pages of hits), or found they use a different definition.

Does anyone have any other examples of an interval scale that fits the definition the way I use it?

Thanks in advance for any reply.