number line

The same axis with a unit attached, a zero, and ticks. Now distance is measurable and a threshold has a value you can compare against. Positions can be checked by someone else, and the gap between two marks can be added up or divided. The cost is that you can only draw what you are willing to measure, so a number line quietly narrows the question to the measurable part of it.

The same axis with a unit attached, a zero, and ticks. Now distance is measurable and a threshold has a value you can compare against. Positions can be checked by someone else, and the gap between two marks can be added up or divided. The cost is that you can only draw what you are willing to measure, so a number line quietly narrows the question to the measurable part of it.

Example

Best when the quantity has a unit you already track, and you want the gap to be arithmetic rather than a feeling.