Sun Clock!

Do you know what is a Sun Clock? Do you know how it works? Do you even know that there is a sun clock in San Francisco? Read the text below and find out the answers to these questions.

Sun Clocks are clocks that use the movement of the Sun to mark time. They are also called sundial clocks. The Sun casts a shadow on the triangular pointer called gnomon. There are numbers all the way around the circle and based on where the shadow is you can know what time it is! That is the way that people used to know the time hundreds of years ago.
One of the disadvantange is in the winter time, on cloudy/rainy days and at night you cannot know the time by this kind of clock. Another negative point is that you can only know the hour of the day, not the minutes.

Well, the fact is that there is one sun clock in San Francisco! It is in the Golden Gate Park, in front of the de Young Museum! It is near the places to leave the bikes!

Hope you can find it and learn a little bit of this old invention!