MONDAY Oct.17 C DAY Aim: Why does the moon go through phases? DO NOW: Define the following words using your textbooks: -Synodic Period -Sidereal Period -Lunar eclipse -Umbra -Penumbra -Total Lunar Eclipse

- Looking at the moon every night we see it following its orbit around earth and cycling through its phases 3-1: CHANGEABLE MOON

 MOTION OF THE MOON -Moon revolves counterclockwise around Earth Moons orbit is tipped a little over 5˚ - moons path takes it slightly north and then slightly south - Always somewhere near the ecliptic - Moves rapidly against the background of the constellations - As moon orbits around Earth its shape changes from night to night in a month long cycle 3-1: CHANGEABLE MOON

 CYCLE OF PHASES 1.Moon always keeps the same side facing Earth 2. Changing shape of moon as it passes through its cycle of phases produced by sun illuminating different parts of the side of the moon you can see 3. Orbital period of moon around Earth – sidereal period (27.32) Length of the lunar phase cycle – synodic period (29.53) - Phases of the moon are dramatic 3-1: CHANGEABLE MOON

3.1: CHANGEABLE MOON

Common misconception People think something is wrong if they see the moon during the daytime Gibbous moon is visible in the day time ( quarter and crescent moon is also but harder to see when the sub is above the horizon ) “Dark side of the moon” – No permanently dark side of the moon - Any location on the moon has sunlight for two weeks and is in darkness for two weeks People act up at full moon - Statistical studies of records from schools, prisons, hospitals, and so on show no evidence 3.1: CHANGEABLE MOON

-Cycle of phases have been observed for billions of years -Occasionally – moon displays more complicated moods turns cooper – red in a lunar eclipse 3.1: CHANGEABLE MOON

-Cycle of phases have been observed for billions of years -Occasionally – moon displays more complicated moods turns cooper – red in a lunar eclipse 3.1: CHANGEABLE MOON

TUESDAY Oct.18 D -DAY Aim: What causes a lunar eclipse? DO NOW: Define the following words using your textbooks: Totality Partial lunar eclipse Penumbral lunar eclipse Solar eclipse Total solar eclipse Partial solar eclipse

 Earth’s Shadow -Earth’s shadow point directly away from the sun -Lunar eclipse occurs at full moon if moons path carries it through the shadow of Earth -Most full moons pass north or south of Earth’s shadow and there is no eclipse 3.2: LUNAR ECLIPSE

-If the moons encounters Earth’s Shadow, sunlight is cut off, and the moon grows dim -Consists of two parts Umbra – region of total shadow Penumbra – sunlight is dimmed but not extinguished 3.2: LUNAR ECLIPSE

-The umbra of Earth’s shadow is over three times longer than the distance to the moon and points directly away from the sun -When the moon’s orbit carries it through the umbra it has plenty of room to become completely immersed in shadow 3.2: LUNAR ECLIPSE

 Total Lunar Eclipse -Once or twice a year, if a full moon passes through Earth’s shadow, sunlight is cutoff, and the moon darkens in a lunar eclipse -When moon is totally eclipsed it does not disappear 3.2: LUNAR ECLIPSE

-It receives no direct sunlight but sunlight that is bent or refracted through Earth atmosphere -During totality the eclipsed moon looks copper-red because of sunlight refracted through Earth’s atmosphere 3.2: LUNAR ECLIPSE

-How dim does it get? Depends on if the Earth’s atmosphere is cloudy Depends on the amount of dust in Earth’s atmosphere ( volcanic eruptions) If the moon’s orbit carries it through the center of the umbra 3.2: LUNAR ECLIPSE

-Timing depends on where the moon crosses Earth’s shadow Crosses through the center of the umbra - maximum length Total lunar eclipse may take nearly six hours 3.2: LUNAR ECLIPSE

 Partial and Penumbral Lunar Eclipses -If the moon only grazes the umbra, the eclipse is a partial lunar eclipse -If the moon enters the shadow of the penumbra but not the umbra, the eclipse if a penumbral lunar eclipse 3.2: LUNAR ECLIPSE

Wednesday Oct.19 E -DAY Aim: What causes a solar eclipse? DO NOW: Define the following words - Small-angle formula - Path of totality - Apogee - Perigee - Annular eclipse - Photosphere - Corona - Chromosphere - Prominences - Diamond ring effect

-Solar Eclipse occurs if a new moon passes between the sun and the Earth and the moon’s shadow sweeps over Earth’s surface along the path of totality -If the moon covers the disk of the sun completely, you see a total solar eclipse – inside the path of totality -If the moon covers only part of the sun you see a partial solar eclipse – just outside the path of totality -Small angle formula allows you to calculate an object’s angular diameter from its linear diameter and distance. Angular diameter of the sun is about 0.5 degrees 3.3: SOLAR ECLIPSE

 Moons Shadow -To see a solar eclipse you have to be in the moon’s shadow -Consists of the umbra of total shadow and penumbra of partial shadow 3.3: SOLAR ECLIPSE

-When the moon is near perigee, the closest point in its orbit, its angular diameter is large enough to cover the sun’s photosphere -If the moon is near apogee, the farthest point in its orbit, it looks too small and can’t entirely cover the photosphere. A solar eclipse occurring then would be an annular eclipse (annular eclipse swept across the US on May 10, : SOLAR ECLIPSE

 Features of a Solar Eclipse -Solar eclipse begins when you first see the edge of the moon approaching the sun -The moment when the edge of the penumbra sweeps over your location 3.3: SOLAR ECLIPSE

-During a total eclipse of the sun, the bright photosphere of the sun is covered and the fainter corona, chromosphere, and prominences become visible -Sometimes at the beginning or end of the total phase of a total solar eclipse, a small piece of the sun’s photosphere can peek out through a valley at the edge of the moon and produce the diamond ring effect 3.3: SOLAR ECLIPSE

 Observing an Eclipse -Common misconception Sunlight is more dangerous during an eclipse Looking at the sun is always dangerous and can burn the retinas of your eyes 3.3: SOLAR ECLIPSE

-Safest way to observe the partial phases of a solar eclipse is by pinhole projection (fig 3-12 pg 43) -Only during totality, when the photosphere is completely hidden is it safe to look at the sun directly 3.3: SOLAR ECLIPSE

Solar Eclipses must occur at new moon Lunar Eclipses must occur at full moon 3.3: SOLAR ECLIPSE

-Moons orbit is tipped a few degrees from the plane of the Earth’s orbit; -most new moons cross north or south of the sun, and there are no solar eclipses in those months -most full moons cross north or south of Earth’s shadow, and there are no lunar eclipses in those months 3.3: SOLAR ECLIPSE

Conclusion questions: (use your notes) 1.Draw the positions of the Earth, sun, and moon during a full moon 2.Draw the positions of the Earth, sun, and moon during a new moon 3.Using figure 3-12 on pg. 42 and the text book describe what pinhole projection is 3.3: SOLAR ECLIPSE

Thursday Oct.20 F -DAY Aim: How can eclipses be predicted? DO NOW: Define the following words -Eclipse season -Nodes -Lines of nodes -Eclipse year -Saros cycle

Making exact eclipse predictions requires a computer and proper software Ancient astronomers could make educated guesses as to which full moons and which new moons might result in an eclipse 3.4: Predicting Eclipses

Reasons to reproduce their methods: 1.Important chapter in the history of science 1.Illustrate how apparently complex phenomena can be analyzed in terms of cycles 1.Exercise your scientific imagination and help you visualize Earth, the moon, and the sun as objects moving thorough space 3.4: Predicting Eclipses

 Conditions for an Eclipse -The moon’s orbit crosses the ecliptic at two locations called nodes, and eclipses can occur only when the sun is crossing a node -During these periods, called eclipse seasons, a new moon will cause a solar eclipse and full moon will cause a lunar eclipse 3.4: Predicting Eclipses

 The View from Space -An eclipse season occurs each time the line of nodes points towards the sun -Since the orbit of the moon precesses, the nodes slip westward along the ecliptic, and it takes the sun only about 347 days to go from a node around the ecliptic and back to the same node -Eclipse year 3.4: Predicting Eclipses

Take out your moon clock and answer the following questions – review for quiz tomorrow!! 1.Determine the phase of the moon -The moon rises at 6 pm -The moon sets at 9 pm -What phase would be in for a lunar eclipse -What phase would the moon be in for a solar eclipse - A few days after waxing crescent SUMMARY QUESTIONS

 The Saros Cycles -Eclipses follow a pattern called the saros cycle -After one saros of 18 years and 11 1/3 days, the pattern of eclipses repeats -Some ancient astronomers knew of the saros cycle and used it to predict eclipses 3.4: Predicting Eclipses