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UNIVERSITA DEGLI STUDI DI CAGLIARI Dipartimento Ingegneria del Territorio MECHANICAL AND CHEMICAL RELIABILITY OF MINE WASTE MATERIAL FOR ROAD EMBANKMENT AND SUBGRADE S. PORTAS, M. CONI, F. MALTINTI, A. LIPPI, F. PISANU 2011 TRB Waste Management & Resource Efficiency Workshop "Sustainability and Liability in Transportation" July 25th - 27th, 2011 in Portland, Oregon UNIVERSITA’ DEGLI STUDI DI CAGLIARI Dipartimento Ingegneria del Territorio

Do Now In your notebook, answer the following question in complete sentences: What causes the seasons?

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Do NowIn your notebook, answer the following

question in complete sentences:

What causes the seasons?

Why do we have seasons?

Seasons

Rotation vs. Revolution

• Rotation – The Earth spinning on its axis (Causes night and

day)– 1 rotation = 1 day (24 Hours)

• Revolution – The Earth orbiting around the sun – 1 revolution = 1 year (365 Days)

Why do we have seasons?NOT because we are

closer or further from the sun

Earth tilts on its axis 23.5 degrees and creates our seasons

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Location 1Summer Solstice

June 20th/21st

Longest Daylight Hours of yearSun Directly Overhead at 23.5 N (Tropic of

Cancer)North Pole receives 24 hours of sunlight

Alaska – 24 hours of sunlight!

Midnight Baseball

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Location 3Autumnal Equinox

September 22nd/23rd Equal Daylight Hours and Nighttime HoursSun Directly Overhead at Equator

Easy way to remember: EQUAL, EQUATOR, EQUINOX

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Location 5Winter Solstice

December 21st /22nd Shortest Daylight HoursSun Directly Overhead at 23.5 S (Tropic of

Capricorn)North Pole receives 24 hours of darkness

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Location 7Vernal Equinox

March 20th/ 21st

Equal Daylight Hours and Nighttime HoursSun Directly Overhead at Equator

Easy way to remember: EQUAL, EQUATOR, EQUINOX

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2Summer Autumn

WinterSpring

What do 2,4,6, and 8 represent?

2 – Summer (Daylight Hours Decreasing)

4 – Autumn (Daylight Hours Decreasing)

6 – Winter (Daylight Hours Increasing)

8 – Spring (Daylight Hours Increasing)

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Southern HemisphereSeasons are OPPOSITE in the Southern

Hemisphere

Q: If I want to go skiing in June, where should I go??

A: Southern Hemisphere!

In your NB’s Answer the following:Southern Hemisphere:

Solstice / EquinoxDateDay light hoursWhere is the sun overheadSouth Pole (if anything)

Location 1:Winter SolsticeJune Short Daylight hoursSouth Pole 24hrs

DarkSun at 23.5 North

Location 5:Summer SolsticeDecemberLong Daylight hoursSouth Pole 24hrs

LightSun at 23.5 South

Location 3:Vernal EquinoxSeptemberEqual Daylight hoursSun at Equator Location 7:

Autumnal EquinoxMarchEqual Daylight hoursSun at Equator