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How to Make a Mini Water Clock

Water clocks stand among the earliest time-keeping devices. According to The National Institute of Standards and Technology, the Egyptian Pharaoh Amenhotep I's entombment circa 1500 BCE included one of the earliest water clocks. The Greek version, clepsydras---"water thieves," date from 325 BCE. Keeping time requires a reliable and measurable action, such as the shadow on a sundial or sand filling an hourglass. Constructing a water clock involves experimenting with one of humanity's oldest timekeepers. This project uses common household supplies and observation time for setting the timepiece.

Things You'll Need

Adult assistant (for kids' project)
Small can
Cutting board or other work surface to hammer on
Nails in different sizes
Hammer
Strong clear jar or vase with an opening small enough for the can to stand on
Pitcher
Water
Food coloring (optional)
2 self-adhesive labels, such as for file folder
Scissors
Waterproof felt-tip marking pen
Clock or watch with a second hand

Instructions

- 1
  Fill the can with water and set it on top of an open jar or vase. Check that the lower container will support the can without the risk of toppling over. Find a heavier jar, if needed.
- 2
  Empty the can and turn it upside down on the cutting board. Hammer a nail into the middle of the bottom of the can to make a hole in the can.
- 3
  Fill the can over the sink---or with it resting on the jar for a classroom demonstration---and watch the water flow. If the water flows evenly and steadily, it will work for the mini water clock. If the water drips or dribbles, empty the can and make the hole larger with a bigger nail. Empty the can.
- 4
  Fill a pitcher with water. Add food-coloring if desired. The color makes it easier to see the time from across the room.
- 5
  
  Add food coloring to the water clock.
  
  Remove the backing from a self-adhesive label and affix it vertically to the jar or vase from the bottom to as high toward the top as it reaches. Add a second label beginning from the end of the first label to extend the label to the top of the mini water clock container. Use scissors to cut any excess label paper at the top of the container.
- 6
  Place the can on top of the jar or vase. Check the time on the clock or watch. Watch the second hand. Pour water into the can to fill it. Note the time to the second as the water starts running in the mini water clock.
- 7
  Use the marking pen to draw a line on the label even with the water level in the mini water clock at set intervals, such as every five minutes. Write the number of minutes on the label. For example, write "5," "10," and "15" on the lines for the water levels. A mini water clock measures a short amount of time due to the limited size of the water reservoir.

Artifacts