Final answer:
Rating marks refer to the degree graduations on measurement tools such as thermometers and rulers. The spacing of these marks can indicate whether they represent Celsius or Fahrenheit on thermometers, or millimeters, centimeters, and inches on rulers. The difference in spacing is due to the different scales and units these marks represent.
Step-by-step explanation:
Rating marks can be placed in different contexts depending on the object or concept being measured. In the case of a thermometer, for instance, the rating marks refer to the degree graduations that indicate temperature. Celsius and Fahrenheit are two scales used on thermometers, and they have different spacing between the graduations because the scales rise at different rates relative to each other (one degree Celsius is wider than one degree Fahrenheit). Therefore, you could determine which side of the thermometer is Celsius and which is Fahrenheit by examining how the degree marks are spaced. In addition to thermometers, rating marks may also refer to measurements on rulers or other measuring tools. On a ruler, rating marks could be indicated as millimeter marks, centimeter marks, or inch marks, where again, the spacing of these marks determines the unit they represent. For instance, on rulers used in the United States, the customary and metric units are often shown side by side, so the millimeter and centimeter marks will be closer together compared to the inch marks.