Constellations along the Zodiac - Sun’s path • The path of the Sun The 13 Zodiacal constellations that (_______) was an our Sun covers-up (blocks) in the important part of ancient astronomy course of one year • The planets and Sun (used to be only 12) represented deities, and their positions were significant • Aquarius • Leo • Most ancient • Pisces • Libra astronomers were • Aries • Virgo also in the astrology • Taurus • Scorpius business • Gemini • _________ • Cancer • Sagittarius • Capricornus North Star Aquarius Pisces Capricornus Aries 1 day Sagittarius Taurus 365 days Scorpius Libra Gemini Virgo Cancer Leo Figure 1 The Zodiacal Constellations that our Sun covers-up (blocks) in the course of one year (only 12 are shown here) North Star North Star W Aquarius Aquarius Pisces Capricornus Pisces Capricornus Aries Aries 1 day 1 day What time is it Sagittarius Sagittarius Taurus Taurus 365 days Scorpius 365 days Scorpius for the Libra Libra Gemini observer? Gemini Virgo Virgo Cancer Leo Cancer Leo Figure 1 E Figure 1 Which What is the name constellation is the Taurus Taurus of the Aries Sun in front of for Aries Gemini Gemini constellation that the situation South South would appear on Cancer Pisces shown? Cancer Pisces the observers W Figure 2 – What it E Figure 2 – What it Eastern Horizon? would look like if you would look like if you were the observer in were the observer in Western? Figure 1 Figure 1 1 North Star W Aquarius 12 hours later Pisces Capricornus Aries what object will Lecture-Tutorial: Seasonal 1 day Sagittarius Taurus be at the Stars (page 7) 365 days Scorpius Libra position that Gemini Virgo Cancer Leo Taurus is in • Work with a partner! E Figure 1 now? • Read the instructions and questions carefully. • Discuss the concepts and your answers with one Taurus 18 hours later another. Aries Gemini where will the • Come to a consensus answer you all agree on. South Cancer Pisces Sun be? • If you get stuck or are not sure of your answer, ask another group. W Where will E Figure 2 – What it • If you get really stuck or don’t understand what the would look like if you Scorpius be? were the observer in Lecture Tutorial is asking, ask me for help. Figure 1 How can we describe the motion of the sun The changing position of the Sun during the year! in the sky? meridian X Zenith or overhead east south west How can we describe the motion of the sun in the sky? Where is the Sun at noon today? meridian zenith zenith here or there? LUNCH!! AM or ante PM or post meridian meridian east south west east south west 2 What about the path of the Sun? Where is the Sun throughout the year? Mar 21 June 21 zenith (Vernal) zenith Summer and Solstice Sept 21 What about (Autumnal) there tomorrow at Equinox noon? JUST A LITTLE LOWER !! Dec 21 Winter Solstice east south west east south west Position of the Sun when photographed during the day of the winter and summer solstice Altitude of the Sun Animation: As we watch the animation, pay attention to • Where the sun rises and sets • Altitude of the sun at mid-day Also, watch how the shadow changes during a day and over the course of the year. The Reason for the Seasons Reason for the Seasons Hypothesis: Seasons are caused by the Earth moving closer to or farther from the Sun. • The seasons are caused by the tilt of the Earth’s 1. Data: When things are ______ to the a light source (like the Sun) they get ______. axis • In Summer, the Sun’s rays are ____ ______ 2. Data: Northern hemisphere has summer in _______, _______, and and the days are _______ ________; Southern hemisphere has summer in _______, _______ and _________ • In Winter, the Sun’s rays are ____ ______ and the days are ________ 3. Data: Earth’s distance from the Sun hardly changes in the course of a year. (about __%) – Earth is closest to the Sun on _________ __ The Seasons do NOT occur because the Earth gets closer or farther from the Sun Can #2 be true if our hypothesis is correct? 3 Reason #1: More or Less Intense Sunlight Reason #2: Longer or Shorter Days • A _____ beam of light shines on a smaller area than a _______ beam. • So a _____ beam is more intense _______ ____/____ ______ ______ _______ _______ ________ ________ 4.