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Seasons on Earth

Seasons on Earth. Butler Middle School 8th Grade Science Bob, Paul, Ms Adams, Oct 25, 2012 8th Grade Science. The Observed Data: 4 Seasons. Autumn or Fall. Winter. Summer. Spring. imgres. We can explain the 4 seasons using Models of the Earth and Sun. Scientific Model.

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Seasons on Earth

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  1. SeasonsonEarth • Butler Middle School • 8th Grade Science • Bob, Paul, Ms Adams, Oct 25, 2012 • 8th Grade Science

  2. The Observed Data: 4 Seasons Autumn or Fall Winter Summer Spring imgres

  3. We can explain the 4 seasons using Models of the Earth and Sun

  4. Scientific Model • Representation of an object for study and understanding (very common in Science) • Models can be physical and/or conceptual - Model leg in 7th grade life science - Computer model of a large weather system

  5. Spherical Earth Model Equator Earth rotates on N-S axis onceper day

  6. Earth-Sun Model(evolved over 100’s maybe 1000‘s of years) Earth revolves around the sun once per year + a little bit

  7. orbital plane Earth’s Orbital Plane Points to Polaris (North Star) to Polaris perpendicular to orbital plane 7

  8. Rotate and Revolve • Rotation: spinning like a top - Earth rotates on its axis once per 24hr - Causes day & night • Revolution: 1 object moving around a 2nd object - Earth revolves around sun once per year: 365 days + 1/4 day • Leap Year - Every 4 years February has an extra day • 4 years = (365 + 365 + 365 + 366) = 1461 days

  9. Comparing Diameters Earth Sun Sun ≈ 109 x Earth

  10. Sun illuminates Earth The Sun is a huge ball of fire - sends energy (light & heat) to the earth - 1/2 of earth is always illuminated - day - 1/2 of earth is always in the dark - night

  11. Energy distribution from Sun S slanted hit large area (cooler) U small area (warmer) direct hit N

  12. Energy distribution from Sun

  13. Understanding the Seasons • It’s all in the tilt • Summer: - Earth is tilted toward the sun, we get a more direct hit, so it’s warmer • Winter: - Earth is tilted away from the sun, we get a slanted hit, so it’s cooler • No tilt means 1 Season!

  14. Understanding Summer and Winter Winter in the North Summer in the North ☹ ☺ S ☺ ☹ U night day N South South From summer to winter earth revolves half-way around Sun

  15. Vernal Equinox March 20 Autumnal Equinox Sept 22 Vernal Equinox March 20 Summer Solstice June 21 Winter Solstice Dec 21 Special Days

  16. Earth Sun Model

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