Lesson 8: The Ancient Roots of Science
In this lesson, we will talk about scientific thinking and how Astronomy is
often considered the oldest science. We will also learn about the Egyptians and
their contributions, and the development of the solar and lunar calendars.
Scientific thinking is based on everyday observations and trial and
error experiments. Science in
its modern form requires painstaking attention to detail, testing each piece of
information to ensure that it is reliable, having a willingness to discard
beliefs that are not consistent with observable facts about the physical world.
Astronomy is considered the oldest science. While it was not practiced the
same way in ancient times, there were still amazing achievements in astronomy.
Ancient people used observations of the sky to keep track of time, seasons and
to aid in navigation. The length of our day is the time it takes the Sun to
orbit the sky once. Ancient peoples used to tell time by observing the Sun's
path through the sky. Some cultures used sundials. The Egyptians used obelisks,
which functioned as simple clocks. At night time, ancient people also estimated
time from the position and phase of the Moon or by analyzing constellations
that were visible.
The seven days of the week are
named after the seven major astronomical objects that were known in ancient
times, including the Sun, Moon, and the five planets easily visible to the
naked eye - Mercury, Venus, Mars, Jupiter, and Saturn.
The first known clocks can be traced back to the Egyptians some 4,000 years ago.
The Egyptians were also responsible for creating our framework for hours that
we use every day. They divided daytime and nighttime each into 12 equal parts,
which came to be 12 hours for a.m. and 12 hours for p.m.
The word 'a.m.' stands for ante meridian which is Latin for "before the middle
of the day." The word 'p.m.' stands for post meridian which is Latin for "after
the middle of the day."
Many cultures built structures such as the Temple Mayor in modern day Mexico
City (formerly the Aztec city called Tenochtitlan) and aligned city buildings
with cardinal directions of north, south, east and west to keep track of the
rising and setting positions of the Sun. This also helped in tracking seasons.
The first written calendars were based on the Moon. The lunar calendar has the
same moon phase on the first day of each month. A lunar calendar has 12 months,
with roughly 29 to 30 days per month. A full 12-month lunar calendar has 354 or
355 days, or about 11 days less in a year than a solar calendar. This calendar
is still in use in some parts of the world and in the Muslim religion.
Today, we use a solar calendar - one that is synchronized with seasons so that
solstices and equinoxes fall approximately on the same days every year. Lunar
and solar calendars can be synchronized by using a timing coincidence: the
lunar phases repeat on the same solar dates every 19 years. If there is a full
moon on Feb 11, 2018, there will be a full moon 19 years later on February 11,
2036. To take advantage of this fact, the Jewish calendar adds a thirteenth
month to certain years in order to keep the lunar calendar roughly synchronized
to the seasons.