Water Clock

In the picture

1. 1Upper tank with an overflow spout: keeps the water level constant
2. 2Drip hole: lets out a thin, steady stream
3. 3Float: rises as water gathers in the lower tank
4. 4Pointer on the marked scale: moves upward to show the hour

Examples

• An hourglass: sand falls steadily to mark time.
• A bucket under a dripping tap: the rising water shows how long it has dripped.

Quiz: Water Clock (Age 11)

1. 1

   Why does the upper tank have an overflow spout?

   • It makes the water drip faster as the day goes on.
   • It stops water from flowing into the lower tank.
   • It keeps the upper water level constant so the drip rate stays steady.
2. 2

   What happens to the float as water gathers in the lower tank?

   • It sinks to the bottom of the tank.
   • It rises.
   • It stays at the same height.
3. 3

   How does the water clock show the hour?

   • A pointer moves past marks on a scale.
   • The drip hole gets wider each hour.
   • The upper tank empties once every hour.

The answers, each with its explanation, are in the app. This quiz is free there while the lesson is in the free week.