You will need:
- Large plastic bottle
- Tape + indelible marker
- Scissors
- Styrofoam cup
- Water
- Timer
Much like a sand glass, use a water bottle to create a water clock or a clepsydra (ancient Greek water clock) and keep time.
INSTRUCTIONS
- Firstly, ask an adult to help you cut 2-3 inches off the top of a plastic bottle.
Try placing the styrofoam cup into the bottle. It should fit at the mouth of the
cut-out bottle. - Next, make a hole at the base of the styrofoam cup, and place it back on top
of the bottle. - Take tape and stick it vertically from the bottom of the bottle till the mouth
of the bottle. Repeat by sticking a second tape next to the first. - Now, ask your friends to help you.
- While one friend pours water into the cup slowly, ask the second friend to
keep an eye on the timer. Make sure your friend
keeps pouring water slowly so that at any given
time half the cup may be full. - As soon as 30 seconds are up, your friend on the timer should tell you to make a mark on the tape, at the water level. Repeat this for a span of 5 minutes, making a mark every 30 seconds.
- Repeat this process on the next tape.
This time, keep an interval of 1 minute.
RESULT
Water clocks have existed for a long time. By creating your own home-made version, you can note down your observations and figure out whether the markings made by you are equal or not. Also, reverse the experiment with the markings in place, and find out whether the water clock can be placed as a reliable method for keeping time.