Sundial

HOW

1. Based on the position of the shadow cast by the sundial, read the sundial.
2. Adjust the time by the adjustment read from the diagram in the centre of the sundial:

• find the corresponding month and the corresponding point on the curve on the horizontal axis;

• read the number of minutes to be added to the time indicated by the shadow at the point corresponding to this point on the vertical axis.

3. Compare the adjusted value with the official time.

WHY

The Earth rotates around its axis from west to east. Sunlight falls on the Earth at different angles and from different directions – depending on the day of the year and the time of day.

Knowing the regularities governing the apparent movement of the sun across the sky, it is possible to select an appropriate scale. This allows the current time to be determined based on the shadow cast by the sundial and with the appropriate correction. Of course, this is possible as long as the sun is not obscured by clouds.