Rotate the sundial until it agrees with the
time shown on your watch. Fasten the sundial in place with a second
screw. This watch shows eight in the morning, the sundial is set
with the edge of the shadow along the 8:00 AM line. Your
sundial works best when set to standard time, not daylight saving time.
If your sundial is set to standard time you will have to add one hour to
the time during summer months.
Your sundial uses binary numbers, follow
this link for an explanation of binary numbers.
The sundial above is indicating 11:00 AM.
In the example below the sundial is showing 8:00 AM.
Using the sun to determine time is a complicated process.
Here are some links with more information about sundials.
Sundials from NASA
(Includes an excellent graphic showing how angles change for
(design a sundial for different latitudes)
This project is suitable for high school or senior
elementary classes, supporting both the astronomy part of a science curriculum
and aspects of the math curriculum - binary numbers and geometry.
The hila binary sundial uses binary numbers instead
of the usual Roman numerals.
Computers use binary math, here is how it works.
Regular decimal numbers use 10 symbols, the common numbers
0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.
Binary math uses only two symbols, 0 and 1.
We use coloured beads on our sundial. "0" is represented by
white and "1" is represented by a colour.
We are using "4 bit" binary numbers, represented by 4 beads.
Each bead location has a "value".
The bead on the extreme right has the value 1, the next bead's
value is 2, then 4 and 8 at the left end.
To determine the decimal value of a binary number add up the
values of the coloured beads (remember white is "0").
For instance 5 = 4 + 1.
Here is a table that shows some of the decimal values for
a 4 bit number.