Using the position of the Sun, you can tell what time it us by making one of these sundials. The Sun will cast a shadow onto a surface marked with the hours, and the time-telling gnomon edge will align with the proper time.


In general, sundials are susceptible to different kinds of errors. If the sundial isn’t pointed north, it’s not going to work. If the sundial’s gnomon isn’t perpendicular, it’s going to give errors when you read the time. Latitude and longitude corrections may also need to be made. Some designs need to be aligned with the latitude they reside at (in effect, they need to be tipped toward the Sun at an angle). To correct for longitude, simply shift the sundial to read exactly noon when indicated on your clock. This is especially important for sundials that lie between longitudinal standardized time zones. If daylight savings time is in effect, then the sundial timeline must be shifted to accommodate for this. Most shifts are one hour.


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Comments

7 Responses to “Sundial”

  1. Aurora Lipper says:

    Sure, cardboard should be fine.

  2. Wild_Taco119 says:

    Can you use cardboard

  3. The simple sundial should be pointed so that the line marked 12 is facing north.

    With the intermediate sundial one yard stick should be sticking straight out of the grass.

    With the advanced sundial the point of the gnomon is pointing north. (The gnomon is the part of the sundial that casts a shadow.

  4. ericksonnationmom says:

    which way do you point the first two sundials???

  5. Sure! You can use any straight edge that’s long enough.

  6. Melanie Church says:

    Hello.Can you use something else other than a ruler to make the sundial straight? Thank you.

  7. Juliet Smith says:

    The Gnomon in the first video is backward.