Star WARS

A LONG TIME AGO IN A GALAXY FAR, FAR AWAY (OR ….WELL NOT TO FAR

FROM HERE)

IT IS A PERIOD OF CIVIL UNREST IN MR. KNOWLES FRESHMEN IIS CLASS

REBEL STUDENTS HAVE BEGUN STRIKING AGAINST THE NEW EVIL

CALLED…..

EMPRESS ADAMS (DUH DUN DUH)

OH WAIT…………….THAT’S NOT THIS LESSON (SORRY)

Choose your side! Federation or Rebel Alliance?

Engage: ConstellationsConstellation:

Roughly ____ constellations in all (same number as piano keys)• Most are visible from North America at some time during

the year

the pattern of stars seen in the sky, and refer to a specific region in the sky

88

Cultures & Constellations

Different cultures grouped some of the same basic stars.

Often varying interpretations • Example: “The Big Dipper (North America)

• “The Wagon” or “The Plough” (Western Europe)

• Tail of the “The Great Bear” (Ancient Greeks)

• Leg of an Ox (Egyptians) • “Stag” (Siberians)• Is the “Big Dipper” a

Constellation?• Nope it is an asterism

Why do constellations move across the sky?

Why do Constellations seem to move across the sky from East to West?

When can the Northern Hemisphere see the stars in the Southern Hemisphere?

• Apparent motion of the stars is the result the Earth’s rotation and revolution

• Through the year, the constellations shift gradually to the west. This is caused by Earth’s orbit around our Sun. In the summer, viewers are looking in a different direction in space at night than they are during the winter

• Never. The southern sky is below our horizon therefore out of our viewable sky

Zodiac• Zodiac-

• Importance:

• How many (Remember video: “The Universe”):

a narrow band in the sky in which the movements of the major planets, Sun, and Moon take place, astrologically divided into twelve sections named for the major constellations.

The annual cycle of the zodiac was used by ancient cultures to determine the time of year.

• There are 13 astronomical zodiac constellations: Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpius, Sagittarius, and Ophiuchus.

• What is light pollution?

• What is the Dark Sky Association in relation to preserving dark skies for star viewing?

Light Pollution and Dark Sky Pollution• is excessive, misdirected, or obtrusive artificial

light

• is to preserve and protect the nighttime environment and our heritage of dark skies through environmentally responsible outdoor lighting.

EXPLORE: Stellar ParallaxParallax:

Stellar Parallax:

Astronomical Unit:

Light Year:

Parsec:

Question: How do I explain that if I keep driving across the state the sun “appears” to follow me?

is a displacement or difference in the apparent position of an object viewed along two different lines of sightis the effect of parallax on distant stars in astronomy.

It is parallax on an interstellar scale, and it can be used to determine the distance of Earth to another star

distance from Earth to the Sun

It is the distance that light can travel in one year

parallax in arc seconds – 1” shift in in star = 206,265 AU= 1pc

Explore: WavesWaves:

Wave motion: transfers energy from one point to another, often with no permanent displacement of the particles of the mediumThey consist, instead, of oscillations or vibrations around almost fixed locations.

Crest, Trough, Amplitude: shown aboveWavelength:

Frequency:

Period:

Speed = DistanceTime

is a disturbance or oscillation that travels through space and matter, accompanied by a transfer of energy.

distance between a crest and the adjacent crest, or a trough and the adjacent trough.

which is the number of waves passing through a given point during the interval (related to wave speed)

the amount of time required to complete one full cycle of the wave.

Explain: MediumWhat is a medium?

How do waves travel differently in different mediums?

What is pitch?

Speed = wavelength (λ) X

frequency

is the matter a wave travels through, water, air, and steel

because the atoms in different objects are packed differently causing the motion in solids to go quick and the motion in gases to go slow

A high pitch sound corresponds to a high frequency sound wave and a low pitch sound corresponds to a low frequency sound wave.

Movement of WavesTransverse:

Compressional:

Sound Waves: Transverse or

oscillations occurring perpendicular (or right angled) to the direction of energy transfer

whose direction of vibration is the same as their direction of travel, aka longitudinal waves

Compressional waves

• Name the different types of EM Waves

Explain: EM SpectrumWhat are Electromagnetic Waves?

Waves that carry energy and radiation.Higher Frequency SHORTER wavelength

Lower Frequency LONGER Wavelength

• Gamma• X-ray• UV• VISIBLE

(ROYGIV)

• MICROWAVE

• RADIO/TV• FM "frequency modulation"• AM stands for "amplitude

modulation,"

Explore/Explain: Brightness

&LuminosityApparent Brightness:

There are two factors that determine how bright a star appears:

Luminosity:

How does the Inverse Square Law relate to luminosity and apparent brightness?

• AB= 4d2

• What is flux? The rate of transfer of energy over a given surface area

L

is how bright a star . appears

• its energy output per second (i.e. luminosity) • distance.

is the of light it emits from its surface.actual amount

• At a particular Luminosity, the more distant an object is, the fainter its apparent brightness becomes as the square of the distance.

• determine the magnitude and spectral class of a star. It is the rate of transfer of energy across a given surface

Stars and Wavelength

• Because stars emit light with different wavelengths, they have different colors.

• Stars do not just emit one wavelength of electromagnetic radiation, but a range of wavelengths. If you look at the amount of light a star gives off at different wavelengths, you would get a graph like the one shown below

The wavelength at which a star emits the most light is called the star's peak wavelength. The diagram below shows that this star has a peak wavelength of 4000 Angstroms.

Emission and Absorption Spectrum• Absorption

The strong colored bands in the emission spectrum are shown as a compliment in the absorption spectrum as black lines

The bolder and darker the black line in absorption the stronger the emission line colored wavelength in the emission spectrum

Intensity Graphs reflect the strength of emission as peaks downward but higher on the graph on the y-axis when intensity of wavelength is greater

HR DiagramWhat is Wien’s Law and how does it help determine the temperature of stars?

• λmaxT=b

• What is a Cepheid star?

• Period of Cepheid star:

• Star Classifications: Stars are classified by their spectra (the elements that they absorb) and their temperature. There are seven main types of stars. In order of decreasing temperature.

• Observe the peak wavelength of the intensity spectrum then use the following equation

• Special stars that cycle from dim to bright in a regular pattern

long periods are more luminous and have more power

: O, B, A, F, G, K, and M

HR Diagram• HR Diagram: is a scatter graph of stars showing the relationship

between the stars' absolute magnitudes or luminosities versus their spectral types or classifications and effective temperatures. • Are not pictures or maps of the locations of the stars. • they plot each star on a graph measuring the star's absolute

magnitude or brightness against its temperature and color.

http://www.youtube.com/watch?v=EjMNNpIksaI

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