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Secondary sourcePainting26 June 2008

Cross-section of Heron's Fountain

Hugh Young · 26 June 2008

A modern diagram showing how the siphon-based fountain described by Hero of Alexandria actually works.

This diagram explains the siphon fountain device described by Hero of Alexandria.

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Diagram of Heron's fountain in cross-section. A blue-filled basin at top has a sloped rim, with a blue spout tube rising from its base. Below, an upper container is connected by tubes to a lower container, and a blue tube runs from the basin down to the lower container. Orange tubes and yellow blocks show the connections between the parts.
Cross-section diagram of Heron's fountain, by Hugh Young, 2008.

About this source

What it is

Created in 2008 by Hugh Young, this diagram shows a cross-section of a practical version of Heron's fountain, also called Heron's siphon. It illustrates how water flows between a basin and two containers using air pressure.

Why it matters

Hero of Alexandria described a fountain that appeared to produce a jet of water without any outside pump. This diagram explains that the apparent paradox is solved by the overall downward flow of water through the system. It shows how ancient engineering ideas, attributed to Hero, continue to be explained and tested using clear modern diagrams.

Look closer

  • How does the diagram explain why the fountain is not actually breaking the rules of gravity?
  • What do the different colored tubes and containers represent?
  • Why might a modern illustrator want to clarify an ancient device that seems paradoxical at first glance?

This painting is part of the curated material that grounds the AI version of Hero of Alexandria on Humy.ai — when students ask about related events, the AI can quote it and cite it.

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