Science Experiments Ideas
World time clock
The earth rotates in 24 hours from west to east once on its
axis. In this time the sun shines on all regions of the globe one
after the other and determines their time of day. To enable a
practical calculation of the time, the earth is divided into 24 time
zones, which are very simply shown on the map below. Since
in a few areas, which belong together, a uniform time has been
introduced, the boundaries of the time zones sometimes run
along state boundaries. For example, Mexico has Central time. The West European countries
including Great Britain has together with the Middle European countries, Middle European time.
According to the map, when it is 13.00 hours there it is only 7 oclock in the morning on the East
Coast of the U.S.A. in Japan it is already 21 .00 hours and on the right edge dateline a new day is
The time zones are shown on the world time disk pictured below. Copy or stick this onto a piece
of cardboard and cut it out. Colour the panel corresponding to time zone were you live red.
Remove the casing and glass from an alarm clock, push the minute hand through the hole in the
paper disk and fix it firmly to the hour hand. Make sure that the red coloured panel is exactly over
the hour hand. If you rotate the disk with this, it should not stick. The clock will tell you all time of
the day on the earth.
Read off first on the red panel the
time of the place where you live.
If you rotate the disk to the left,
you will find the time zones of
places west of you. In each panel,
the time is an hour earlier. If you
rotate to the right, you will find the
places east of you. In each panel
the time is an hour later. The outer circle continues into the inner circle at the crossed arrows and
vice versa. For example in New York it is 6.15 in the morning. Then it is already 20.15 in Tokyo
and in New Zealand a new day will begin in 45 minutes. Or in London it is 20.03. What time is it in
San Francisco? Look at the world map San Francisco lies in the time zone of Los Angeles. On the
rotating disk go to the left to the Los Angeles panel. The time is 11.03.