In the final unit of our Light & Sound class, we studied the way time works in the universe. Our action project was to invent a device that could tell time. Mine is based on the rotation of sunflowers– specifically, sunflower buds, since I learned that the flowers do not rotate to face the sun once they are fully grown. A diagram of my invention is below, along with a paper describing how it works and the mathematical and cultural influences behind it.

Screenshot 2013-02-28 at 3.20.10 PM

Before sunflowers bloom, their buds rotate to follow the sun through its daily rotation. The device I created uses the flower to tell time by putting a clock face at the top of the stem. A pendant attached to the bud drops down to the clock face, so as the sunflower moves to face the sunlight, the end of the pendant moves along the numbers of the clock face, which correspond to hours, to show what time it is.

In order for the pendant to correspond correctly to the current time, the numbers that mark each hour must be evenly spaced. To find the space between each number, you must first find the clock face’s circumference. The equation for this is


with d being the diameter and C the circumference. Since the diameter of the clock face is 3 inches, the circumference would be 3π inches. Divide this by twelve, the number of hours, and you get 0.25π inches between each number.

This math is nearly identical to the way the clock face is made for a sundial. The device itself is also very similar in that it is based on the rotation of the sun. However, this device is missing the key component of the sundial, which is the shadow cast upon each hour. The pendant replaces it as a marker, and the flower’s rotation is follows the sun, rather than a stagnant piece of the sundial being affected by the sun.

Sunflowers were domesticated around 5000 years ago. The oldest evidence of this was found in Tabasco, Mexico. Other sites of ancient domestication have been found in the southern United States (Kris). They have been used throughout history for ceremonial purposes, food, and flavoring, but they are famous in European culture for being the subject of Van Gogh’s series of sunflower paintings (Wikipedia). His paintings are famous for showing their simple but colorful beauty (Van Gogh Gallery).

Like Van Gogh’s paintings, this device is based on a simple phenomenon. It is not complicated technology; it employs nature. The fact that a plant can respond relatively quickly to the change in light is an impressive reminder of what can be accomplished without electricity or any other man-made technology. While the device and even the concept of time are both man-made, this sunflower clock creates a more meaningful connection to nature for the user.



Hurst, K. Kris. “Sunflowers.” Archaeology., n.d. Web. 06 Mar. 2013.
“Vincent Van Gogh: Sunflowers.” Vincent Van Gogh Gallery. Van Gogh Gallery, 2013. Web. 06 Mar. 2013.
“Sunflowers (series of Paintings).” Wikipedia. Wikimedia Foundation, 23 Feb. 2013. Web. 06 Mar. 2013.