Welcome

Please register to have access to more features!

It is highly recommended that you have Javascript enabled; many features will not work unless you do. The recommended browsers are Firefox and Chrome; the board is also NOT mobile-friendly.

Please invite your friends!

If you were referred by someone (ex. me, Jessica) please put their username in the referral box on the registration page. Ask them if you don't know their username.

If you are visiting for TESTING PURPOSES ONLY, this is the test account information:


Username:
Test
Password: test123



Select a forum to post in:

Earth Science

Science topics

Moderators: Jessica, Teachers

Looking for a topic?
View the Science Topics Directory to find topics quicker under different kinds of science.

Earth Science

Post Number: #1  Postby Jessica » May 20th, 2014, 1:18 pm

Four realms of Earth
1. Geosphere: the solid Earth
2. Hydrosphere: the water around us
3. Atmosphere: the air
4. Biosphere: life on sea, land, and air


Geosphere: Largest realm. Earth’s radius~ 6400 km

Three major layers in Geosphere:

1. Crust: Outermost very thin layer. Hard or soft rocks of various colors (Fig. 1-3) beneath soil or ocean water. About 5-65 km (3-40 mi) thick. Similar to skin on apple.

2. Mantle: Composed mostly of solid rocks and pools of hot liquid rocks (magma). Largest (~80% volume) of Geosphere. About 2900 km thick.

3. Core: Innermost, most dense and hot. Consists of Iron and Nickel. Outer core is liquid or molten Ni-Fe and inner core is solid Ni-Fe. About 3500 km.


Hydrosphere: consists of all Earth’s water.
Oceans ~97.5%
Glaciers ~ 1.8%
Ground water ~0.63%
Atmosphere ~ 0.001%
Streams and lakes ~ 0.01%
~12 km deep maximum.

Atmosphere: Mixture of gases (99% of atmosphere is within about 30 km high)
Nitrogen ~78%
Oxygen ~21%
Inert gases ~1%
CO2 ~ 0.03%; methane, Hydrogen, etc. are very small amount. This atmosphere supports life on our planet and shields it from high radiational heating and cooling. Circulation of atmosphere maintains temperature.


Biosphere: ~15 km. Includes the hydrosphere, upper geosphere and the lower atmosphere. Changing very rapidly with time (Fig. 1-6) that could threaten the environment.


Geologic Time: Age of Earth ~4.6 billion years. In the primordial stage, there was no crust, no ocean, no living organisms, and the atmosphere was mainly composed of hydrogen and helium (light) gases. Life existed as early as ~3.8 billion years (single celled organisms). About 543 million years ago, more complex life forms evolved. Dinosaurs existed about 225 million years to almost 65 million years (MYR).

Homosapiens came about 4 million yrs ago (single stroke of a file on middle finger nail if the whole life of Earth is as long as your arm).
  • 0

User avatar
Jessica
Board Owner
Topic Author

Founder
Sapphire
Sapphire
 
8 years of membership8 years of membership8 years of membership8 years of membership8 years of membership8 years of membership8 years of membership8 years of membership
 
Posts: 3,469
Topics: 1,244
Articles: 30
Joined: December 22nd, 2010, 8:04 pm
Local time: October 19th, 2019, 11:41 pm
Last Visit: Online
Location: Pennsylvania
Gender: Female
Cash on hand: 4,767.32
Bank: 138,647.08
Reputation: 148
Medals: 20
#1: July 2012 1st Place (1) R-Contest #1 First Place (1) Best staff member 2013 (1) Easter Egg Hunt 2013 (1) Graphic Drawing Participant (1) 1 Year (1) 2 Years (1) 3 Years (1) 4 Years (1) 5 Years (1)
6 Years (1) 7 Years (1) 8 Years (1) Founder (1) Highest Rep (1) Referrer (1) Top poster (1) Facebook group (1) Pin-Board (1) Article Author (1)
Referrals: 27
Blog: View Blog (478)
Subject(s): Chinese, Math
Global Moderator
Admin
Moderator

Re: Earth Science

Post Number: #2  Postby Jessica » June 9th, 2014, 8:27 pm

GEOSPHERE

  • Planets accreted from dust into planetesimals
  • Planetesimals clumped together to form planets
  • Colliding pieces (and radioactivity) created heat, warming the young Earth to melting
  • This ended (or Earth started) about 4.6 billion years ago
  • 3 major layers
    • Dense metallic core - Outer core liquid, inner core solid, 6000°C Ni-Fe
    • Less-dense rocky mantle - Changes with depth, some parts solid, others weak and plastic-like, flowing slowly
    • Even less dense surface crust - Crustal material varies widely

LITHOSPHERE
  • 0

User avatar
Jessica
Board Owner
Topic Author

Founder
Sapphire
Sapphire
 
8 years of membership8 years of membership8 years of membership8 years of membership8 years of membership8 years of membership8 years of membership8 years of membership
 
Posts: 3,469
Topics: 1,244
Articles: 30
Joined: December 22nd, 2010, 8:04 pm
Local time: October 19th, 2019, 11:41 pm
Last Visit: Online
Location: Pennsylvania
Gender: Female
Cash on hand: 4,767.32
Bank: 138,647.08
Reputation: 148
Medals: 20
#1: July 2012 1st Place (1) R-Contest #1 First Place (1) Best staff member 2013 (1) Easter Egg Hunt 2013 (1) Graphic Drawing Participant (1) 1 Year (1) 2 Years (1) 3 Years (1) 4 Years (1) 5 Years (1)
6 Years (1) 7 Years (1) 8 Years (1) Founder (1) Highest Rep (1) Referrer (1) Top poster (1) Facebook group (1) Pin-Board (1) Article Author (1)
Referrals: 27
Blog: View Blog (478)
Subject(s): Chinese, Math
Global Moderator
Admin
Moderator


Return to Science Topics

Login  •  Register
cron
Reputation System ©'