physics

1. PHYSICS - is a branch of science that
deals with the relationship of matter
and energy. It covers everything from
the interaction of subatomic particles
and celestial bodies in the universe
together with the energy associated
with the interaction.
AIM- to unify all the laws governing
matter, motion, and energy.

2. Unit II
FORCE, MOTION AND
ENERGY FROM EARTH TO
COSMOS

3. Chapter 6
Deals with how early astronomers
perceived earth and its motion,
together with other celestial
bodies in the solar system.

4. Target
Understand the greek views of matter,
motion, and the universe
And explain what the Greeks
considered to be the three types of
terrestrial motion.

5. Early view of the Universe
Celestial sphere – where the
stars and planets are though to
be located .

6. Early vies of the Universe
• Were once gods and served as guides
for the peoples lives.
• The location of the stars was used in
navigation
• Astronomical events were perceived
as divine messages

7. Greek astronomers

8. What were the three types of
terrestrial motion according to the
Greeks?
Voluntary motion
Natural motion
Violent motion

9. • Voluntary motion - Motion made by humans
and animals while involuntary motion is made
by plants and animals.
• Natural motion – due the notion of the
equilibrium. Every object tends to go back to
its natural place.
• Violent motion - happens when the object is
in state of nonequilibrium due to external
forces.

10. Earth’s motion
Diurnal motion
Annual motion
Precession of the equinoxes

11. Diurnal motion
Sun rises at the east horizon
and sets down at the west
horizon.
motions that repeat
daily

12. Annual motion
• Apparent shift in location of the stars in the sky.
• Due to earths revolution around the sun.
• Refers to the yearly revolution of the earth to its
orbit traveling 365 and ¼ days.

13. Precession of the equinoxes
• Gradual change in the orientation of the
earths axis.

14. The axis of inclination rotates in full circle in
about 26 000 years.

15. Solstice and equinox

16. The terms "solstice" and "equinox" are
related to specific positions of the
Sun's in the sky throughout the year.

17. Summer solstice- Summer solstice is the longest
day of the year for each hemisphere. For
northern hemisphere observers, the June solstice
(the 20th or 21st), marks the beginning of
summer. In the southern hemisphere, that's the
shortest day of the year and marks the beginning
of winter. Six months later, on December 21st or
22nd, winter begins with the shortest day of the
year for northern hemisphere people. It's the
start of summer and the longest day of the year
for people south of the equator. This is why such
solstices are now called the December and June
solstices, rather than "winter" or "summer"
solstices.

18. • The term "equinox" comes from two
Latin words aequus (equal) and nox
(night). The Sun rises and sets exactly
due east and due west on the
equinoxes, and day and night are of
equal length.

19. • Solstice and equinoxes, happen
because of the tilt of earths axis
and position of the sun

20. 2Na + Cl₂ 2NaCl