The Strange Time of the Sundial - PowerPoint PPT Presentation

1 / 4
About This Presentation
Title:

The Strange Time of the Sundial

Description:

Title: The Strange Time of the Sundial Author: FTL_USER Last modified by: FTL_USER Created Date: 7/31/2006 10:38:38 PM Document presentation format – PowerPoint PPT presentation

Number of Views:51
Avg rating:3.0/5.0
Slides: 5
Provided by: FTL61
Category:

less

Transcript and Presenter's Notes

Title: The Strange Time of the Sundial


1
The Strange Time of the Sundial
  • O Lord God! You have made the heavens and earth
    by your great power nothing is too hard for
    you!
  • Jeremiah 3217

2
The Facts, Please!
  • Ancient people did not measure time by hours and
    minutes or even by days. They were most
    concerned with seasons of the year in order to
    know when to plant their crops. They judged the
    seasons by the constellations of stars, which
    appeared in different parts of the sky in
    different seasons.
  • The oldest device for measuring hours of the day
    is the sundial. It is based on the fact that the
    shadow of an object will move from one side of
    the object to the other as the sun moves from
    east to west during the day.

3
More Facts, Please!
  • The most common kind of sundial is made up of two
    parts-the dial face and the pointer, called the
    gnomon. The round dial face is horizontal and
    divided into quarters by lines running toward the
    four points and sometimes half or quarter hours.
    The pointer is a metal triangle, placed in the
    center of the dial and pointing toward the North
    Pole. As the sun moves across the horizon, the
    shadow of a sundials pointer moves across the
    dial face.

4
Final Fact, Please!
  • In the story of King Hezekiah, he had a sundial
    in his courtyard called the dial (or steps) of
    Ahaz. This may have been a stairway going up
    the sides of an obelisk, with its point serving
    as a pointer. Its shadow would be on the highest
    step at high noon and in the morning and evening
    on the lowest steps on one side or another. The
    steps may have measure time at the rate of a half
    hour per step.
Write a Comment
User Comments (0)
About PowerShow.com