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The Nebular Theory, Matter, and Light

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The Nebular Theory, Matter, and Light Terrestrial, Jovian, and dwarf planets Nebular theory Matter atoms and molecules Kinetic and potential energy – PowerPoint PPT presentation

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Title: The Nebular Theory, Matter, and Light


1
The Nebular Theory, Matter, and Light
  • Terrestrial, Jovian, and dwarf planets
  • Nebular theory
  • Matter atoms and molecules
  • Kinetic and potential energy
  • Electromagnetic spectrum
  • Spectroscopy
  • Goal du jour
  • Understand more about matter, and how we use
    light to study the Universe.

2
Four classes of solar system objects
  • Terrestrial planets
  • Jovian planets
  • Dwarf planets
  • Jovian moons

3
Solar System models
  • A good formation model should explain all these
    things.
  • ?See details of the Nebular Theory, p79.
  • ? Pay particular attention to origin of two types
    of planets.

4
The basics of matter
  • Atoms
  • Often considered the building blocks of matter,
    but atoms have internal structure.
  • Atoms consist of a nucleus, and a surrounding
    cloud of electrons.
  • The atomic nucleus
  • Protonsmassive, charge
  • Neutronsmassive, no charge
  • Electrons
  • Low mass, - charge
  • of electrons of protons

5
The basics of matter
4 2
Elemental notation He
1H 1 proton (and 1 electron) 2H 1 proton, 1
neutron (and 1 electron) 4He 2 protons, 2
neutrons (and 2 electrons) Isotopes The same
element (proton ), but different masses (i.e.,
different numbers of neutrons). Ex
He Ions Atoms temporarily stripped of one or
more electrons.
3 2
6
The basics of matter
  • Molecules are atoms that have been bound together
    by mutual attraction.
  • Simple compounds
  • O2, N2
  • Complex compounds
  • CO2, H2O, C12H22O11 (sucrose), DNA
  • Organic compounds
  • Contain C-H bonds

7
Phases of matter
Phases Solid Liquid Gas (Plasma)
Solid
Freezing? ?Melting
Sublimation? ?Deposition
Evaporation? ?Condensation
Liquid
Gas
8
Types of energy
  • Kinetic EnergyEnergy exhibited by motions
    speed, vibrations, rotations.
  • Potential EnergyStored energy at the top of a
    hill, a compressed spring, Emc2
  • Radiative EnergyEnergy stored in photons,
    technically in each photons magnetic and
    electric fields, hence electromagnetism.
  • TemperatureA measure of how much kinetic energy
    is in a sample of molecules

9
Electromagnetic Radiation
  • Photon
  • A self-propagating packet of pure energy.
  • c
  • All photons all travel at the speed of light,
    the highest speed at which anything in the
    universe can travel.
  • Frequency
  • Higher energy photons have a higher frequency.
  • Wavelength
  • Higher energy photons have smaller wavelengths.
  • Types of electromagnetic radiation
  • radio? microwave ? infrared ? ROYGBIV ?
    ultraviolet ? x-rays ? Gamma rays

10
Spectra
  • Spectrum
  • A graphical display of the different kinds of
    photons in a beam of radiation.
  • It might be portrayed as a line-graph, or (if
    visible light) as a multicolored display.
  • This kind of smoothly varying, peaking spectrum
    is called a continuum spectrum.
  • Continuum spectra are produced by opaque, glowing
    objects.

11
Continuum spectra
  • The wavelength peak of a spectrum is affected by
    the glowing objects temperature.
  • Very hot objects glow blue.
  • ?We can take the temperature of objects by
    looking at them!

12
Electrons in atoms
  • To understand the other kinds of spectra, we must
    first understand how electrons in atoms interact
    with photons.
  • Electrons can jump from one level to another in
    atoms.
  • An electron dropping towards the atom releases
    energy in the form of a photon.
  • An electron must absorb a photon in order to jump
    to a larger orbit.
  • Every different kind of element has a different
    set of electron orbit sizes. This will be useful.

13
Types of spectra
  • Continuum spectrum
  • An opaque object will produce a continuum
    spectrum.
  • Emission spectrum
  • A transparent gas cloud, excited by some energy
    source, will produce an emission spectrum.
  • Absorption spectrum
  • A continuum source, with a transparent gas cloud
    in front it, will produce an absorption spectrum.
  • Chemical analysis
  • Since every atom has its unique set of electron
    orbits, each atom has a characteristic spectrum.
  • ?We can learn about the composition of gas
    clouds, or planets, or stars in space by looking
    at them!

14
Gas discharge tubes
  • Gas normally does not conduct electricity
  • 1)High voltage applied across gas drives
    electrons across the gap.
  • 2)Electrons ram into the gas atoms in the tube,
    exciting the bound electrons (i.e., gives the
    electron energy).
  • 3)The bound electron settles back to its ground
    level, releasing the stored energy as a photon.
  • 3)Repeat
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