Science Magazine: HERON'S FOUNTAIN BY MARTA MIELGO

Heron's fountain is a hydraulic machine invented by the 1st century AD inventor, mathematician, and physicist Heron of Alexandria.

Heron studied the pressure of air and steam, described the first steam engine, and built toys that would spurt water, one of them known as Heron's fountain.

This model of Heron's foutain was made by Marta Mielgo as a project for the science fair. She used 3 plastic containers, that were 5l bottles and rubber tubes. Also silicon to airtight seal the tubes to the bottles. She stained the water with ink to obtain more visible effect of the movement of the water.

How to make it

In the following description, we will call the 3 containers:

(A) Basin (top)
(B) Water Supply (middle)
(C) Air Supply (bottom)

BUILD

Start with a basin (A), open to the air. Run a pipe from a hole in the bottom of that basin (A) to an airtight air supply container (C).
Run another pipe from the top of the air supply container (C) up to nearly the top of the airtight water supply container (B).
A pipe should run from almost the bottom of the water supply container (B), up through the bottom of the basin (A) to a height just above the basin's rim. The fountain will issue upwards through this pipe.

MAKE IT WORK

Initially, the air supply container (C) should contain only air; the water supply container (B) should contain only water.
To start the fountain, pour water into the basin (A).
The water from the basin (A) flows by gravity into the air supply container (C). This water forces the air in (C) to move into the water supply container (B), where the increased air pressure in (B) forces the water in (B) to issue out the top as a fountain into the basin (A). The fountain water caught in the basin (A) will drain back to the air supply container (C).
The flow will stop when the water supply container (B) is empty.