What does the difference between two inches on a ruler represent?

The difference between two inches on a ruler represents equal intervals, which reflects the nature of the measurement system being used. A ruler is a tool specifically designed to provide measurements in widely accepted units such as inches or centimeters, where each division corresponds to an equal increase in value. This means that the distance between any two consecutive inch marks is the same, ensuring that each unit of measurement is consistent and uniform.

The concept of equal intervals is fundamental in measurement because it allows for straightforward comparisons of length. For example, if you measure 2 inches and 4 inches, the difference is 2 inches, which clearly shows a consistent spacing in value that holds true across the entire scale of the ruler. This consistent spacing is crucial for accurate measurement and ensures reliability in various applications, from everyday tasks to scientific discoveries.