The name of the book is Science Wizardry for Kids, but out
by Barron's. It has a section that is called "Tell The Time"
which features:
- Find Out How Fast The Earth Turns
- Outrun the Earth
- Build a Sun Clock
- Create Your Own World Clock
- Three Ways to Mark the 24 Hours on Your World Clock
- Places and Times for Your World Clock
- Swing in Time
- String Together a Pendulum
Build a Sun Clock
Before people had watches or mechanical clocks, they had sun
clocks. You ought to know how to tell time by the sun. It's
the natural way.
Here is what you need:
Scissors, 2 pieces of heavy cardboard, a drawing compass, a
pen, a ruler, household glue, masking tape, a directional
compass, a watch or a clock.
Here is what you do:
1. With scissors, cut one piece of heavy cardboard into a
square 12 inches by 12 inches (30 cm x 30 cm)
2. Use the drawing compass to draw a half circle. Place the
point of the compass at 6 inches (15 cm) the midpoint of one
of the sides of the 12in (30cm) square.
3. Draw a triangle on the second piece of cardboard. Here
is how. Measure 12 inches (30 cm) up from one corner, and
make a mark. Then make another mark 12 inches (30cm) over
from the same corner. use your ruler to draw a line from
one mark to the other, and back to the first mark. Now you
have a triangle that is 12 inches (30 cm) by 12 inches
(30 cm) by just under 17 inches (43cm).
4. Cut out the cardboard triangle.
5. Use the glue and masking tape to secure a 12 inch (30cm)
side of the triangle upright across the center of the
cardboard square. Secure the triangle so that it divides
the half circle in two.
6. Take your sun clock outside on a bright day. Use the
directional compass to position the sun dial so that the
cardboard triangle points directly North.
7. As soon as your watch or clock reaches an hour mark,
note where the shadow falls on you sun clock. Label that
hour. Then come back in an hour and label the next the
next hour. As the shadow moves, label each hour until you
have all the hours of the day.
Enjoy.
Regards
Tim Sweet
M.O.S.T Watch & Clock Co.
http://www.tritco.com/most/most1.html
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