Warm-up- Take out your science notebooks. - In the notes section, on a blank sheet of paper complete the

following activity.

- Draw the diagram. Fill in the correct phases of the moon as seen from earth. Label each phase.

Sun Earth

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Eclipsesand Tides

http://solarsystem.nasa.gov/multimedia/gallery/Earth_Moon.jpg

Intro

•The Moon orbits at an angle with respect to the Earth’s orbit around the Sun.

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Ecliptic planeMoon’s orbital plane

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Eclipses• Two kinds: Solar and Lunar

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Vocabulary

Umbra - is the innermost and darkest part of a shadow, where the light source is completely blocked. An observer in the umbra experiences a total eclipse.

Penumbra -is the region in which only a portion of the light source is blocked. An observer in the penumbra experiences a partial eclipse.

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Solar Eclipse• When the Moon’s shadow covers part of Earth• Moon is in between Sun and Earth• When viewed from Earth, moon covers part or all of sun • Only happens at New Moon

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Total Solar Eclipse• Observers in the “umbra” shadow see a total eclipse (safe to view the Sun); can

see the corona• Those in “penumbra” see a partial eclipse—not safe to look directly at Sun• Only lasts a few minutes• Path of Totality about 10,000 miles long, only 100 miles wide

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Photo of a Total Eclipse

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http://sunearthday.nasa.gov/2006/multimedia/gal_008.php

Upcoming Solar Eclipses• May 10, 2013, annular eclipse—not visible in USA

• Next Total Solar Eclipse in continental USA—August 21, 2017

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Eclipses

• Lunar eclipse: A lunar eclipse occurs when the moon passes through the shadow of the earth.

• Can be partial or full eclipse

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When the Earth’s shadow covers the Moon, we have a lunar eclipse

Why is the Moon red during an eclipse?• The Earth’s atmosphere filters some sunlight and allows it to

reach the Moon’s surface• The blue light is removed—scattered down to make a blue sky

over those in daytime• Remaining light is red or orange• Some of this remaining light is bent or refracted so that a

small fraction of it reaches the Moon• Exact appearance depends on dust and clouds in the Earth’s

atmosphere

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Upcoming Lunar Eclipses

• Apr. 25, 2013, Partial eclipse (not visible in US)• May 25, 2013, Penumbral eclipse• Oct. 18, 2013, Penumbral eclipse• Apr 15, 2014, TOTAL ECLIPSE –visible here

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Sun

Moon

Earth

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Tides• Tides: alternating rise and fall in sea

level produced by … gravity of the moon.

• In one day: • 2 high tides, 2 low tides

• The Moon’s gravity tugs on the Earth. • It pulls the most on the part of Earth

closest, which raises the oceans.• It pulls the least on the part of Earth

that’s farthest, which allows the oceans and atmosphere to be further from the Moon (and higher)

• The Sun’s gravity does the same thing, but to a lesser extent.

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Season Vocabulary

•Seasons – A pattern of temperature changes & other weather trends over a year.

Season Vocabulary•E

quator – •I

maginary line which separates the Northern from the Southern Hemisphere

•Earth rotates around an imaginary line running through its center called an

• axis of rotation.• The ends of the axis are the north and south poles.• Earth turns on its axis once in 24 hours.• Earth’s rotation is reason for day & night• The Earth is tilted at about a 23 ½ degree angle from its orbit around the Sun.

•Reason for the seasons:

•Earth’s tilted axis and orbit

Season Vocabulary•A

revolution is the motion of one object around another once.• It takes one year for Earth to make one revolution around the Sun or 365 ¼ days.• Leap year every 4 years – add up ¼ days

•A rotation is one complete spin or turn on an axis. • One rotation takes 24 hours.

Season Vocabulary•S

olstice – •P

eriod of time when one hemisphere gets its maximum area of sunlight, while the other hemisphere gets its minimum amount; the time of year when days are either longest or shortest and the angle of sunlight reaches its maximum or minimum.

•Winter & Summer Solstice– usually 21st of December and June• Winter: Earth is closest to the sun in December but Northern

Hemisphere is tilted away – colder temperatures/shorter days • Summer: Earth is furthest from the sun in June but Northern

Hemisphere is tilted toward the sun – hotter temps/longer days

•Equinox –

•Period of time in an orbit in which sunlight shines equally on the Northern Hemisphere and the Southern Hemisphere; a time of year when daylight and darkness are nearly equal for most of the Earth. (Happens twice a year). Spring & Fall – March & September

Date & Time of Solstices & Equinoxes in 2013

Equinoxes: March 20 2013 11:02September 22 2013 20:44

Solstices: June 21 2013 05:04December 21 2013

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Planet Vocabulary• Nebular Theory –our solar system developed from cloud of dust

and gas

• Inner or rocky planets - Terrestrial• Cratered• Volcanism• Closer to sun – gasses burned away

• Outer planets• Gas giants• Called Jovian planets

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• Distance is measured in miles, kilometers and astronomical units (abbreviated as AU = distance from Earth to the sun or 93,000,000 miles which equals 1 AU)

• Rotation – some have a retrograde rotation which means it spins backwards from all the other planets rotations

• Revolution – time it takes to orbit once around another object

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• Ellipse – elongated oval shape

• Temperature – measured in Fahrenheit, Celsius and Kelvin

• Greenhouse effect – trapping of gasses which doesn’t allow heat to escape – temperatures are extreme

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• Meteoroids, meteors & meteorites – chunks of rock & metals – range in size – called a meteoroid when in space, meteor when it enters Earth’s atmosphere and a meteorite when it hits Earth’s surface

• Asteroid – Large chunks of rock and various metals – range in size from a baseball to house-sized to almost dwarf planet size (Ceres is over 500 miles long)

• Asteroid Belt which is an areas that is in between Mars and Jupiter

• Comets – called dirty snowballs – made up of ice, dust & rock. Have an orbit that they follow. Very elliptical. Oort Cloud as well as Kupier Belt contain millions of comets.

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