A water clock, or clepsydra, was used before mechanical time keeping devices were commonplace. Unlike sundials, which were unusable during cloudy weather, at night or indoors, water clocks were fairly reliable, if not terribly accurate. Homemade water clocks can teach students about science and the history of clock making. It only requires a few basic tools to create a clock that uses water to measure minutes or hours.
Things You'll Need
- Two large eye screws
- Square 12 inch by 2 inch wooden stick
- 8 inch dowel that will fit in the eye screws
- Rubber bands
- Piece of cardboard or sturdy paper
- Two empty 28 oz. metal cans
- Can opener
- Brick or thick books
- Timer or stopwatch
Screw the eye screws into the square stick. Place one eye screw 1 inch below the top of the stick and the other 1 inch above the level of the top of one of the cans.
Thread the dowel through the eye screws and then place the cork on the lower end.
Wrap the rubber band around one of the metal cans and the square stick. Make sure the cork does not rub against the interior of the can; if it does, loosen the eye screws a bit.
Cut a triangle shaped pointer out of the cardboard or paper. Glue it onto the side of the round stick, pointing toward the large stick but not touching it.
Make a tiny hole in the side of the second can close to the bottom by using the can opener; you want it only large enough to allow the water to drip slowly.
Position a brick or a couple of thick books next to the bottom can to use as a platform for the second can. It needs to be slightly taller than the bottom can.
Fill the second can with water and place it onto the platform so that the hole is over the bottom can and is able to drip into it. Start your timer.
Mark the pointer level on the square stick; this will be your starting point. As the water raises, the cork, dowel and pointer will float upward.
Use the marker to draw a mark on the square stick at five-minute intervals. This will be the water clock calibrations.
Tips & Warnings
- Experiment by using different size holes to alter how quickly the water fills up the bottom can, changing the calibration of the clock.
- Photo Credit water image by timur1970 from Fotolia.com