Download Our own Earth`s interior structure, and surface features will be

Hi,
You should begin studying for the first exam scheduled for October 7.
Also HW #2 is due Sept. 30 at 11 am in lecture.
Have a nice weekend.
Mrs. Deming
Lecture Summary (9/21 and 9/23)
Newton’s three laws of motion were enhanced through demonstrations. Examples of
interia were given. The combination of the Moon's inertia (to continue to move in a straight line)
and the Earth's gravity on the Moon (the Moon is accelerated toward the Earth) results in a stable
orbit. Newton's law of gravitation was combined with his second law of motion to show that all
bodies fall to Earth in the same manner, their mass or weight doesn't matter. Newton's third law
is referred to as the “action/reaction” law of motion. Weight is a measure of gravitational force
on a mass. On the surface of a planet, gravitational force, or weight, depends on mass divided by
the radius squared. Demonstrations were done to illustrate many aspects of Newton’s Laws.
The basic characteristics of the Solar System were listed. Any theory attempting to
explain the formation of the Solar System must account for the major differences observed
between the jovian and terrestrial groups and the dynamical characteristics (motions of the
planets). An important consideration is the arrangement of the Solar System in an approximate
plane and the revolution of the planets about the Sun in the same direction as the Sun’s rotation.
The age of the solar system was given as 4.6 billion years old. High-density planets consist
predominately of rocky material while low-density planets consist of mainly light elements, like
hydrogen and helium. The solar nebula theory is the model that best fits the observations.
According to this theory, the Solar System formed from a collapsing rotating cloud (the solar
nebula) comprised of mostly hydrogen and helium.
Condensation of material is temperature sensitive. Only denser, heavier elements
condensed and became trapped in the forming terrestrial planets. Farther from the forming Sun,
ices could condense along with rocky and metallic grains. The composition, mass and density
differences are explained using this model. As masses built up or accreted in the planets, more
and more hydrogen and helium gas especially in the outer solar system was gravitationally drawn
in. Differentiation became important in ordering a planet’s interior structure.
Our own Earth’s interior structure and surface features will be compared to those found
on other planets and moons. The average density of Earth is 5.52 grams per cubic centimeter.
The observation of the lower density found in surface rocks supports the hypothesis that the
Earth is differentiated. Seismic waves are used to probe the Earth's internal structure. It was
discovered that the outer core is molten. Evidence was given to support the premise that the
Earth is differentiated. Magnetic fields were examined.
TERMS you should be able to use:
Inertia, acceleration, force, mass, weight, weightlessness, escape velocity, density, average
planetary density, terrestrial planets, jovian planets, solar nebula, frost line, condensation,
accretion, differentiation, radioactivity, half-life, seismic waves, magnetic field
QUESTIONS you should be able to answer:
1. Give an example illustrating each of Newton's 3 laws of motion.
2. How is orbital motion explained by Newton?
3. Upon what variables does the attractive gravitational force depend?
4. Describe the dynamics of the Solar System.
5. Use the solar nebula theory to describe how astronomers believe the solar system
formed.
6. Account for the differences between the 2 groups of planets using condensation
theory.
7. How do astronomers measure the age of the solar system?
8. How does the average density of the Earth compared to the densities of surface
rocks support the theory that the Earth is differentiated?
9. What have scientists learned from seismic studies of the Earth?
10. How is Earth’s magnetic field generated?