Archive for Class Notes — astronomy
PCC Class Astronomy12 Study Guide and notes
Notes on the study guide for Mr. Sepikas' PCC Astronomy class. Notes are taken from http://encyclopedia.tfd.com/ or wikipedia unless otherwise noted.
1. degrees, minutes, seconds
2. the astronomical unit
3. diurnal motion
4. the north celestial pole
5. zenith, celestial equator, ecliptic, meridian
6. cause of the seasons
7. the equinox and the solstice
8. precession
9. leap year
10. tropical and sidereal year
11. phases of the moon
12. solar and lunar eclipses
13. Eratosthenes and the size of the Earth
Eratosthenes knew that on the summer solstice at local noon in the Ancient Egyptian city of Swenet (known in Greek as Syene) on the Tropic of Cancer, the sun would appear at the zenith, directly overhead. He also knew, from measurement, that in his hometown of Alexandria, the angle of elevation of the Sun would be 1/50 of a full circle (7°12′) south of the zenith at the same time. Assuming that Alexandria was due north of Syene he concluded that the distance from Alexandria to Syene must be 1/50 of the total circumference of the Earth. His estimated distance between the cities was 5000 stadia (about 500 geographical or nautical miles). He rounded the result to a final value of 700 stadia per degree, which implies a circumference of 252,000 stadia. The exact size of the stadion he used is frequently argued. The common Attic stadion was about 185 m, which would imply a circumference of 46,620 km, i.e. 16.3% too large. However, if we assume that Eratosthenes used the "Egyptian stadion"[1] of about 157.5 m, his measurement turns out to be 39,690 km, an error of less than 1%.[2]
Although Eratosthenes' method was well founded, the accuracy of his calculation was inherently limited. The accuracy of Eratosthenes' measurement would have been reduced by the fact that Syene is not precisely on the Tropic of Cancer, is not directly south of Alexandria, and the Sun appears as a disk located at a finite distance from the Earth instead of as a point source of light at an infinite distance. There are other sources of experimental error: the greatest limitation to Eratosthenes' method was that, in antiquity, overland distance measurements were not reliable, especially for travel along the non-linear Nile which was traveled primarily by boat. So the accuracy of Eratosthenes' size of the earth is surprising.
Eratosthenes' experiment was highly regarded at the time, and his estimate of the Earth's size was accepted for hundreds of years afterwards. His method was used by Posidonius about 150 years later.
14. the difference between planets and stars
15. Newton's Laws
16. Kepler's Laws
17. The electromagnetic spectrum and the optical window
18. the speed of light
19. the meaning of temperature
20. the Kelvin scale
21. atomic spectra
22. emission, absorption, and continuous spectra
23. The Rutherford experiment and the discovery of the nucleus
24. refraction, reflection and dispersion
25. refracting telescopes and reflecting telescopes
26. Nicholas Copernicus
27. CCD's
28. telescopes in space
29. Newton's law of gravity
30. the difference between mass and weight
31. the atomic hypothesis
Astronomy Test 2 Study Guide
The following study guide is intended to provide a focus fro your reading and study. It is not intended to be
comprehensive. There may be questions on the test that are not covered by this guide and topics in the guide
that do not appear on the test. Some of the topics may require you to look them up in another book or an
encyclopedia in the school library.
1. size of the photosphere
2. solar granules
3. determination of the chemical composition of the sun
4. appearance of the solar spectrum
5. temperatures inside and on the Sun
6. know what the words photosphere, chromosphere, and core mean
7. why are sunspots dark
8. how do we know that the Sun rotates
9. what is stellar parallax
10. what is proper motion
11. what is the difference between absolute and apparent magnitude
12. what is meant by luminosity
13. what are spectral classes
14. know and understand the Hertzsprung-Russel diagram
15. what are binary stars and what do they tell us
16. what is the material between the stars
17. what is nuclear fusion
18. read the section on the Orion nebula
19. understand the formula E=mc2
20. what is the Pauli exclusion principle
21. what is electron degeneracy
22. what is a pulsar
23. what is a black hole
The following study guide is intended to provide a focus fro your reading and study. It is not intended to be comprehensive. There may be questions on the test that are not covered by this guide and topics in the guide that do not appear on the test. Some of the topics may require you to look them up in another book or an encyclopedia in the school library.
1. Know the names of the planets and their correct sequence from the Sun.
2. Know the difference between the term terrestrial and Jovian planets.
3. Know how the masses of planets are determined.
4. Know what substances make up what are called in space sciences "ices".
5. Know what fraction of the universe is made up of hydrogen and helium.
6. Understand the formation process of the solar system.
7. Know the age of the Earth.
8. Understand the process of chemical differentiation on the Earth.
9. Understand how earthquake waves give us information about the interior of the Earth.
10. What is plate tectonics and how does it explain the mid-Atlantic ridge
11. How did oxygen come to be in the atmosphere of the Earth.
12. How is the magnetic field of the Earth created.
13. Know the relationship between the rotational period of the moon and its orbital period.
14. What are the lunar Maria and what caused them.
15. What caused the craters on the Moon.
16. Understand the theory that best explains the origin of the Moon.
17. Understand what is a scarp on Mercury and what caused them.
18. Know the surface temperature on Venus in Fahrenheit and Kelvin temperature scales.
19. Understand the greenhouse effect and what chemical causes it.
20.What is the optical illusion that caused the apparent "canals on Mars".
21.What is Olympus Mons.
22. What is the evidence for the existence of flowing water on Mars
23. Understand how Jupiter can emit more heat than it receives from the Sun.
24. What material is thought to be responsible for the large magnetic fields on Jupiter and
Saturn.
25. What are the names of the moon of Jupiter.
26. Understand the mechanism that causes the heating of Io.
27. What is the composition of Saturn's rings.
28. Understand the Roche limit.
29. Understand the angle relationship between the spin axis of Uranus and the orbital
plane of Uranus.
31. Know the story of how the plane Neptune was discovered.
32. Know what Bode's law is.
33. Know the location of the asteroid belt in the solar system.
34. Understand the experimental technique for finding the shapes of asteroids.
35. Know what comet nuclei are.
36. What governs the direction of a comet's ion tail.
37. Understand how comets orbit the Sun. Are the orbit random or is there a pattern.
38. What is a "meteor shower" and why are they seen at predictable times of the year.
39. Understand the current thinking on the cause of the deaths of the dinosaurs.
March 15, 2010 · Filed under Class Notes -- astronomy, Student work