Ruler … Why mark mm (millimeters - which aren't numbered) and not the cm (centimeters - which are numbered)? Labeling the 1 as "1 cm" would help a student understand that the numbers refer to the largest markings while the mm refers to the smallest markings. (See neighboring photos). Especially this one. Why manufacturers seem to be STUPID, INCOMPETENT, or both.


I originally took the picture as part of a worksheet to help my students distinguish between imperial and metric measurement. Many tended to get confused, thinking the mm indicates that the numbers are millimeters. So now I look at such loose labeling as a symbol of the incompetence of ruler manufacturers. Usually these same rulers mark the other side as "inches" and the inches are numbered. So why do they mark the metric side "mm" when they number the centimeters??!!


I'd rather they put cm after the number 1, and shrink the mm and nestle it down next to the mm markings, between zero and 5mm. The way they have it is just too ambiguous, especially for people who struggle with the metric system.


For the life of me, I cannot figure out why this picture has more than a couple of views. I put it up more as a joke. If you feel like it, let me know why you are looking at it.

  • rpdexter 8y

    Lol! I looked at this picture b/c I lost my ruler and had to measure something. Therefore, I looked up rulers and this pic came up. This particular picture won't help me b/c it's too big & and it's not the whole thing.
  • Lucy Jaffe 8y

    We'd like to use your picture, is that OK?
  • warty2200 7y

    I came to this pic by looking for pics of Lake Powell. You had a great shot of the lake from a plane heading west. Then I noticed your user name. I love the Islands so I looked around. Found this ruler pic and tried to figure what's wrong with it. Your'e right; it should be marked "cm".
  • allendesarae 7y

    I was trying to get an accurate measurement regarding the toy I just bought.

  • tiny club rock show 6y

    I came by because I'm looking for a photo of a ruler for an art project I'm doing.
  • riad hatem 5y

    have no comet
  • m.renshaw23 5y

    I wanted an image to demonstrate the idea of 'reliability' to a group of students on a research course, and threats to that reliability. So a ruler that we might assume was measured out in inches but had no clear indication that this was the case, seemed a good way to start discussing the subject!
  • Cynthia Cheney 4y

    I was looking for a place to buy the rulers seen in scientific field photos, e.g. indicating size of animal tracks or plants. They have very bold markings including alternating blocks of black and white to make it clear what size the object is.

    But I’m commenting because I can contribute another “incompetent manufacturers“ story. My husband is a textile artist and at one point his work was not coming out quite square. He found out at last that two metal yeardsticks he had bought---not cheap either--- were 1/4 inch wrong. Made in Korea.
  • sagar raste 4y

    Great Shot!!!
    We would be honored to have your photo in our group DSLR Photography Assignments
    Please add your photo to the group pool and submit your entry for assignment "Zero".
  • richardmaun 3y

    i borrowed your super pic for my blog, credited to you. Thanks!
  • Kiffer the Original 3y

    I was looking for something completely different and this came up. I looked because I wanted to know who and why would somebody post a picture of the end of a ruler.
  • Different Apple 2y

    I was looking at your photostream because you had commented on mine. I was confused by the set title 5000+ views and wondered why 5000 people would want to look at a close up of a ruler. Lol
  • Biking Nikon SFO 1y

    Thank you all for your comments!
  • Tina Truelove 1y

    LOL Reading your story made me smile, laugh actually. Well, I wrote an article titled "Kindergarten Thematic Units" and I needed a good photo of a ruler to include in my work. I liked yours. You can see it here:
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Taken on August 8, 2006
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