For our final action project in our STEM class Light and Sound, we were challenged to conceptualize a new way to tell time and then write a report about it. Here is mine!

Time Telling Device

My time telling device is modelled after the hourglass. It uses three different hourglasses of three different sizes to measure seconds, minutes and hours. The hourglass on top measures seconds and once 60 seconds has passed it is half full and a weight sensor causes it to empty into the minute hourglass below it. Similar to the first hourglass, when the minute hourglass has 60 minutes worth of sand in it, it sends the sand into the hourglass below it. The bottom hourglass keeps track of hours, up to 12. Once it is full, a vacuum sucks up the sand into the sand container and the cycle continues. The sand container holds more sand than is needed for 12 hours so during the time that the lowest hourglass is being emptied, the process can continue and not have to wait and become increasingly inaccurate over time. The container has a filter to only let a measured amount of sand out per second so there is a reliability in the amount released.

Below is the math that I did to figure out this. I used pi and the Pythagorean theorem. I had to do a lot of work measuring the volume of cones so I knew how big each of the hourglasses needed to be to accurately measure the amount of time passed and hold the sand that represents 2-1I’m not sure this is the most precise or efficient way to tell time, but I think it is a creative use of the hourglass and could be very visually appealing and interesting if designed correctly. It is a imaginative expression of time made with a lot of thought and care for details and precision. I chose to do this not because it’s the most efficient way to tell time, but because it is innovative and involves the use of a lot of math and accuracy to build and run it.


“Surface Area and Volume: Cylinder, Cone, Pyramid, Sphere, Prisms.” Mathematics. N.p., n.d. Web. 27 Mar. 2013.

“T & K YOUNG.” Hourglass. N.p., n.d. Web. 27 Mar. 2013.

Time for Time. N.p., n.d. Web. 27 Mar. 2013.