Sundials are the most ancient mechanisms for determination of time. Mechanical clocks are considered to be very complex device. Another thing is sundials: a simple stick and shadow on a flat disc. However, like many antique mechanisms sundial is much more difficult than the mechanical one. Because in addition to the dial and the gnomon their integral parts are astronomical objects, the Earth and the Sun, the motion of which relative to each other is subject to much more complex laws than the oscillation of the pendulum, and is not subject to regulation.

Sundial is relatively easy to make, however, deep knowledge in astronomy and trigonometry are necessary to accurately calculate its design. The original reminder of the archaic way of time measurement is a sundial in the rotunda of fountain "Samson" on Kontraktova Square. His teacher Pierre Brulon was from Kyiv-Mohyla Academy. He arrived in Kyiv as a private teacher of French, but was a strong mathematician and topographer (sundial can be seen today in the reproduced building of rotunda). Currently sundials are used as landscape decoration. With the example of sundials parents teach their children the structure of the solar system, and construction of solar clocks with own hands is an exciting occupation for children and adults.