Explain the importance of measurement to a society. Describe the benefits from a standard from of measurement, including the ability for easier trade, construction of buildings and facilitated communication.
Discuss a ruler's markings. Begin by discussing the concept of "inches." Give an example of a common item that frequently measures an inch, such as the length of the tip of your thumb to its joint. State that an ordinary ruler has 12 inches and that the largest black lines on the ruler stand for inches.
Next discuss the individual markings between each inch line. For a ruler marked in eighths, note that there are eight smaller markings between each inch and that the fourth marking between each inch is the half-inch mark. Further note that every second marking between an inch is a quarter-inch.
For a ruler marked in 16ths, note that there are 16 smaller markings between each inch. Further note that every second marking is an eighth of an inch, every fourth is a quarter of an inch and every eighth is a half an inch.
Draw a line on the chalkboard. Make sure all the students can see the chalkboard and the line. Go through the motions of measuring the line: hold the ruler to the line, and then note which mark on the ruler falls at the line's end point. Explain that the ruler's mark that falls at the end of the line notes the line's length.
Instruct each student to draw a line on a sheet of blank paper and measure it, doing exactly as you've done. Walk around and check each student's measurement.
Provide each child with a quarter, sharpened pencil and piece of string. Have the children measure these objects and write down their findings. Check to see how each child progresses.