Mr. Kopp’s 8 th Grade Earth Science class introductions. What is the Scientific Method?. Series of steps that help guide scientific study Must be repeatable (recipe) Validates conclusions . 1) Make an Observation in nature. 2) Identify the problem/ask a question. 3) Conduct Research.
Mr. Kopp’s 8th Grade Earth Scienceclass introductions
What is the Scientific Method? Series of steps that help guide scientific study Must be repeatable (recipe) Validates conclusions
1) Make an Observation in nature
2) Identify the problem/ask a question
3) Conduct Research
4) Formulate a Hypothesis
6) Collect/Analyze Data
7) Draw a Conclusion
8) Present your findings
Fact From Fiction Scientist classify ideas based upon their ability to PROVE their ideas using mountains of evidence and repeatable experiments Scientific Law – description of what scientists find happening in nature repeatedly and in the same way without exception Scientific Theory – a well-tested and widely accepted hypothesis
Scientific Method Keys Terms Data – any set of information Control – part of an experiment that does not change (used for comparison) Variable – part of an experiment that is different
Chapter 1: Introduction to Earth Science
What is Earth Science? The name for the group of sciences that study the Earth and its neighbors in space. Geology Oceanography Meteorology Astronomy Ecology
Geology Physical Geology – studies the processes that shape our planet Historical Geology – attempts to understand the Earth’s long history (timeline)
Oceanography Studies the composition and movement of seawater, as well as, coastal processes, seafloor topography, and marine life.
Meteorology Studies the composition of the atmosphere, local and global weather, and the combined effects of the Earth’s rotation and energy from the sun.
Astronomy Study of the Universe and the Earth’s place in space.
BIG BANG THEORY FORMATION OF THE UNIVERSE!
Formation of the Universe The Big Bang theory suggests that… a highly condensed single point of energy exploded 13-15 billion years ago protons, neutrons, and electrons hydrogen hydrogen formed stars early universe formed
Evidence for the Big Bang Theory 1) Everything in the universe is moving away from everything else… the farther away the object the faster it is moving away. Also known as Red Shift. 2) Residual heat (1-2 degrees above absolute zero) 3) Cosmic Background Radiation (static)
NEBULAR HYPOTHESIS FORMATION OF THE SOLAR SYSTEM
Formation of the Earth NEBULAR HYPOTHESIS– the solar system formed from a giant cloud of gas and dust (nebula)
Nebular Theory Continued 1) A nearby Giant star explodes in a supernova 5 -7 billion years ago 2) The material from this explosion formed a giant cloud of gas and dust – SOLAR NEBULA
Nebular Theory Continued 3) The cloud begins to spin due to a gravitational forces 4) Materials accrete (come together) at the center as the cloud flattens out
Nebular Theory Continued 5) Increased gravity and heat at the center causes immense amounts of material to accrete (come together) at the center (99% of all) – Fusion begins forming our sun
Nebular Theory Continued 6) Meanwhile, due to friction, hundreds of larger chunks are forming in the outer portions of the flattened cloud – Planetismals
Nebular Theory Continued 7) The larger chunks grow faster than the smaller chunks due to higher gravitational force 8) Only the biggest 50 - 100 or so capture all of the other chunks – Protoplanets
9) The biggest ones have enough gravitational pull to capture the lightest gases such as hydrogen and helium, they are also far enough away from the center (cold enough) to capture icy materials such as ammonia and methane – they become the Outer Planets or Gas Giants (After the Sun began fusion, solar wind pushed particles outward to the outer planets causing additional growth)
10) The smaller, closer ones are not large enough and are too hot to capture many gases. They are called the Inner Planets or Terrestrial Planets
Nebular Theory Continued 11) Collisions continue on a massive scale… A mars-sized object collides with the Earth forming our moon 12) Many of the moons of the outer planets were captured by the planet’s gravitational pull
Nebular Theory 1) Supernova creates giant cloud 2) Giant Cloud (Nebula) begins to spin 3) Nebula rotates, flattens, accretion in center (protostar) 4) 100s of planetismals grow in the outer portion of the disk-like cloud 5) Fusion begins – Sun is born 6) 50-100 Proto-planets grow 7) Massive collisions happen - # of proto-planets decrease 8) Inner planets remain small and rocky (due to heat) Outer planet grow huge and gaseous (due to size and cold) 9) moons are capture or created by explosions
Structure of the Earth
Structure of the Earth Inner Core – solid iron and nickel (most dense) Radius of 1,220 km. Density – 13 g/cm3 Outer Core – liquid iron and nickel 2,255 km thick Density – 10-12 g/cm3 Mantle – silicon, oxygen, and magnesium 2,885 km thick, the mantle is 82% of Earth’s volume. Crust – silicon and oxygen (least dense)
Composition of the crust
Types of Crust Continental crust – Underlies the continents. –Avg. rock density about 2.7 g/cm3. –Avg. thickness 35-40 km. –Felsic composition. Avg. rock type = Granite Oceanic crust – Underlies the ocean basins. –Density about 3.0 g/cm3. –Avg. thickness 7-10 km. –Mafic composition Avg. rock type = Basalt/Gabbro
Shape of the Earth Oblate Spheroid - Not a perfect sphere Flatter at the poles, bulges at the equator An object weighs more at the poles- 15N than it does at the equator-14N (distance to the center of the Earth is different)