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- 1. A. Choose the letter of the best answer. For numbers 1 to 3,
use the table below that presents information about stars A, B, C,
and D. Star Color A Red B Yellow C White D Blue
- 2. 1. Which star is the hottest? a. A b. B c. C d. D 2. Which
star is very similar to our sun? a. A b. B c. C d. D
- 3. 3. How do stars appear to move in the night sky? a. From
East to West b. From North to South c. From East to West d. From
South to North
- 4. 4. Stars appear to move in the sky because a. The Earth is
rotating on its axis. b. The universe is expanding. c. The night
sky is rotating. d. New galaxies are formed.
- 5. 5. If you are located at the North Pole, where will you see
the Polaris? a. Overhead b. Just above the horizon c. Around 45
from the horizon d. Polaris will not be seen in the North Pole
- 6. 6. Which constellation is prominently seen in the sky during
summer? a. Orion b. Pegasus c. Hercules d. Virgo
- 7. 7. Based on apparent magnitude, which of the following stars
is the brightest? a. Alpha centauri b. Betelgeuse c. Rigel d.
Sirius
- 8. 8. Why do stars have colors? a. It is because of the
presence of oxygen. b. It is because of the presence of carbon
dioxide. c. It is because of varied temperatures. d. It is because
of the different locations.
- 9. 9. Stars can be found in large groups throughout the
universe. What are these groups called? a. Solar system b. Comets
c. Constellations d. Asteroids
- 10. 10. The star Algol is estimated to be as bright as the star
Aldebaran and have approximately the same temperature as the star
Rigel. Which of the following statement is correct? a. Algol and
Rigel have same color. b. Algol and Rigel have the same brightness.
c. Allgol and Aldebaran have the same in size. d. Algol and Rigel
have the same brightness and color.
- 11. Rigel Sirius
- 12. Definition of terms: Star is a swirling, glowing ball of
gases. Constellation is a group of stars that has a shape
resembling that of an animal, a mythological character, or some
other object. Galaxy is a large constellation or large groups of
gases, dust and stars in space held together by gravity. Type:
Elliptical galaxy, spiral galaxy and irregular galaxy.
- 13. When we look at the night sky, we see thousands of stars.
In reality, there are approximately 400 billion stars in our
galaxy, and there are about 170 billion galaxies. A person can see
only about 3,000 stars on the average.
- 14. Characteristics of Stars Color and Temperature Brightness
and Magnitude of Stars Sizes of Stars Distances of Stars
Composition of Stars
- 15. Characteristics of Stars Color & Temperature - Star
color ranges from red to blue. The color of the star indicates its
surface temperature. - The coolest star is about 2800C at the
surface. These star appear red. The temperature of the hottest star
is about 28 000C or higher. These star appear blue.
- 16. Sun Yellowish, 5500C Stars that are cooler appear orange,
stars that are hotter than the sun appear white.
- 17. Table 1. Color and Temperature of Selected Stars Star Color
Surface Temperature in Celsius Sun Yellow 5,700 Proxima Cantuari
Red 2,300 Epsilon Iridani Orange 4,600 Vega White 9,900 Sirius
White 10,000 Alnilam Blue 27,000
- 18. Figure 2 shows the size of the Sun, the closest star to
Earth, as compared to some other stars that we see at night. As we
can see, the Sun is so small compared to other nearby stars. Also,
Sirius, which appear bigger than Rigel, is actually very small
compared to Rigel. It appears larger only because it is closer to
us.
- 19. Characteristic of Star Brightness - The brightness of a
star as seen from the Earth depends on two factors: distance and
the actual brightness (or absolute brightness) of the star. The
stars brightness as seen from Earth is its apparent brightness,
apparent brightness depends on how far away a star is from the
Earth.
- 20. Astronomers consider the stars absolute brightness when
comparing stars. A stars absolute brightness is the brightness the
star would have if all stars were the same standard distance from
Earth.
- 21. Characteristics of Stars Sizes of Stars - Stars varies in
size, from huge to supergiants to tiny neutron stars. - Astronomers
group stars in to five types: neutron stars, white dwarfs, medium-
sized stars, giants and supergiants.
- 22. Neutron stars are the smallest, it has a diameter of about
16 km. White dwarf is about 7300 km, slightly greater than that of
the Earth. Medium-sized star is about one-tenth the diameter of the
sun. Sun has 1.35 million km in diameter. Giant star is 10 to 100
times that of the sun. Supergiant stars is up to 1000 times the
diameter of the sun.
- 23. Characteristics of Stars Distances of Stars - Scientist use
parallax to determine how far away a star is from Earth. A parallax
is an apparent change in the position of an object caused by a
change in the position of the observer. - The closer a star is to
Earth, the greater its apparent change of position. Very distant
stars seem not to shift position at all.
- 24. Scientists express distances between stars in light years.
A light year is the distance that light travels in one year at a
speed of 300 000 km per second (kps). A light year is about 9.5
trillion km or 9 500 000 000 000 km. The closest star is Proxima
Centauri, 4.2 light years from Earth. Other stars are hundred of
light years away.
- 25. Characteristics of Stars Composition of Stars - Using
spectroscope, astronomers have found that almost all stars have the
same general chemical make-up. The most element in stars is
hydrogen, the lightest element that makes up 60% to 80% of the
total mass of a star. The second element is helium, combination of
H and He make up about 96% to 99% of stars mass. - Other elements
are oxygen, neon, carbon and nitrogen.
- 26. The Polaris Polaris, commonly known as North Star, is the
brightest star in the constellation Ursa Minor (Little Dipper). It
is very close to the north celestial pole, making it the current
northern pole star. Because it lies nearly in a direct line with
the axis of the Earth's rotation "above" the North Pole, Polaris
stands almost motionless in the sky, and all the stars of the
Northern sky appear to rotate around it. In Figure 3, Polaris and
the star trail are seen. Star trail is a type of photograph that
utilizes long-exposure times to capture the apparent motion of
stars in the night sky due to the rotation of the Earth.
- 27. Fig. 3 Polaris and the Star Trail over Mt. Pulag
- 28. In Metro Manila, when you face North, Polaris, which is
11.3 from the horizon, is seen at around 15 due to atmospheric
refraction. In some parts of the country (i.e. Southern
Philippines), it would be very difficult to locate Polaris since
star lights near the horizon are washed out by lights lit by men,
and /or obstructed by man- made or topographical structures and/or
trees.
- 29. Fig. 4 Polaris as viewed from the Philippines (Quezon
City). To locate Polaris, face North and locate the Big Dipper. Two
stars (Merak & Dubhe) in the Big Dipper are called pointer
stars because they seem to point to Polaris.
- 30. Constellation for a certain month: March Night Sky 9pm
- 31. June Night Sky 9pm
- 32. September Night Sky 9pm
- 33. December Night Sky 9pm
- 34. An observer from Earth will be able to see the stars that
are on the night side. The stars on the same side as the sun cannot
be seen because sunlight overpowers all the star lights. During
summer in the Philippines, the constellations of Orion and Taurus
are not visible at night. They will be visible again as the cold
season begins. During this time, Scorpius will not be seen in the
night sky. As the Earth revolves around its orbit, the stars that
were concealed by the bright light of the Sun in the previous
months will appear in the night sky.
- 35. How Early People Used the Constellations While
constellations were associated with religion, they also have
practical uses. Before the calendars, people had no way of
determining when to sow or harvest except by looking at these
patterns in the sky. Ancient people developed a way to remember the
patterns by giving these patterns names and stories. For example,
in the northern hemisphere, the constellation Orion indicates the
coming of cold season. The constellations made it easier for them
to recognize and interpret patterns in the sky.
- 36. For example, Gemini is seen in the Philippines during the
months of April and May. Farmers interpreted the appearance of
Gemini as the end of planting season and it signified rich harvest.
The table below shows how the Matigsalug Manobo of Bukidnon used
the stars and constellations in relation to their agriculture.
- 37. Local Name Month of Appearance Related Agricultural Act.
Western Equivalent Baha Dec to Feb Clearing of forest Taurus
Pandarawa January Start of planning what crops to be planted &
how wide is the area Pleiades Balatik Feruary Start planting &
setting of traps Orions Belt Malihe March Planting of rice,corn
& veggies Gibbang April & May End of planting season,
signifies rich harvest Gemini Malara May Stop planting Canis
Minor
- 38. Lepu Late May Time to clean or clear the fields while
waiting for harvest time Aquila Buwaya June Start of the rainy
season
- 39. Other Uses Another use of constellations was in navigation.
The Polaris is widely used in navigation because it does not change
its position at any time of the night or year. Also, one can figure
out his/her latitude just by looking at how high Polaris appears in
the night sky. This allowed sailors to find their way as they sail
across the seas.
- 40. Group Activity In groups of five, observe the sun by
capturing its image on a cardboard. Obtain a telescope and a square
of white cardboard. Let one member hold the cardboard while another
member holds the telescope in a reversed viewing position in order
to capture the image of the sun onto the cardboard. DO NOT LOOK
DIRECTLY AT THE SUN! Adjust the board and the telescope so that the
image of the sun falls on the board. Focus the telescope until the
suns image becomes sharp. Try to identify sunspots and
prominences.