In this unit of my math and science course, we studied how light and sound can be used to measure time. To my surprise, cultures have been using light and sound for this purpose from the beginning of time. I enjoyed learning about the mathematical and scientific aspects of light and sound for telling time, but as someone who is very interested in history, it was also fascinating to learn about the anthropological and historical aspects of telling time. For our last project as action, we were given the task of designing our own time-telling models that use either sound or light to function. Please view my essay below!

My device is similar to a sundial in that it employs the same measurement tactics. The way my design functions is by using the sun’s rays to determine the time of day. When the sun hits the rectangle, the shadow will reflect at a different place depending on the hour. You can calculate the hour by measuring the degrees that the shadow falls from the rectangle. It is very similar to the sundial, but a little less advanced because it does not have numbers surrounding it like an average sundial. However, this is an advantage because it can be used anywhere in the world at any time so long as the sun is shining and you have a protractor!

The first people to use sundials were the Egyptians in 1500 BCE. The Egyptians used astronomy to develop the concept, and it was a monumental advancement in mankind. Their first primitive design looks a lot like my prototype, but a bit more advanced. This was a revolutionary invention, and greatly altered the way we live today. Sundials have been used by both ancient and modern cultures alike. This is a meaningful invention because as long as there is sunlight this is a 100% sustainable way of telling time.
My design is relatively simple aesthetically– it consists of a 6” tall rectangle made of a sturdy material on a stand so it can be upright.The units used to measure my time-telling device is inches, because I wanted to keep it as simple as possible.

I will employ math by finding the latitude of my exact area, (Chicago, IL) 41.8500° N, 87.6500° W. Once I do that, I can plug that number into a shadow calculator and determine what angle the shadow will fall at any given point in the day. Another way of doing this which is a lot easier and requires less materials is measuring the angle of the shadow with a protractor. By taking that measurement it is easy to determine what the time of day is.



1:00pm –


2:00pm –


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4:00pm –


(Larkrise Web Calculator: Sundial angle calculator, 2013)


•Fitzgerald, Tom. “When Time Began: The History and Science of Sundials.”

When Time Began. N.p., n.d. Web. 06 Mar. 2013.


•Larkrise Web Calculator: Sundial angle calculator. N.d. Raw data.

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