1 / 39

Chapter 7: Atoms and starlight

Chapter 7: Atoms and starlight. Not all of these light sources emit the same kind of light. Fluorescent light. The Sun!. Incandescent Bulb. Halogen bulb. Each part of the EM spectrum provides us with different information.

Download Presentation

Chapter 7: Atoms and starlight

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Chapter 7: Atoms and starlight

  2. Not all of these light sources emit the same kind of light Fluorescent light The Sun! Incandescent Bulb Halogen bulb

  3. Each part of the EM spectrum provides us with different information.

  4. If you pass white light through a prism, it separates into different colors. ROY G B I V spectrum

  5. What can we learn by analyzing starlight? • A star’s temperature • Its composition

  6. An atom consists of a small, dense nucleus (containing protons and neutrons) surrounded by electrons- Model Proposed by Niels Bohr 1913

  7. Atoms are mostly empty space

  8. So if a nucleus the size of an orange (10 cm) was located at the center of the football field, where would the electron be?End Zone?Grandstands?On Campus?In San Jose?

  9. Nucleus

  10. Nucleus Photons (light-waves) are emitted from an atom when an electron moves from a higher energy level to a lower energy level

  11. Nucleus Photons (light-waves) can also be absorbed by an atom when an electron moves from a lower energy level to a higher energy level

  12. Each chemical element produces its own unique set of spectral lines when it is excited

  13. Three types of spectra prism Hot/Dense Energy Source Continuous Spectrum prism Hot low density cloud of Gas Emission Line Spectrum prism Hot/Dense Energy Source Cooler low density cloud of Gas Absorption LineSpectrum

  14. Types of spectra: Some light sources emit all colors (appears as white light). Others emit just a few colors. Some are missing a few colors.

  15. Continuous spectrum is also called a “Blackbody Spectrum”

  16. What color is our 5800K Sun? The Sun emits all wavelengths of electromagnetic radiation (light); however, the wavelengths of light it emits most intensely are in the green/yellow part of the spectrum.

  17. Absorption spectrum: atmosphere of stars

  18. Emission Line Spectrum: Pictorial Graphical

  19. Absorption of light: electrons excited to higher energy levels. Photon is gone!

  20. Absorption Line Spectrum: Pictorial Graphical

  21. The Doppler Effect

  22. V=0 Astronomy Application

  23. An Atom’s Structure: The Bohr Atom

  24. Electron orbits in hydrogen and helium The pattern of energy levels is different for every element.

  25. When electron drops to lower energy level, it releases (emits) a photon. Photons released in random directions.

  26. The energy of the photon depends on the size of the jump between orbits.

  27. Emission spectra of hydrogen and helium

  28. Atomic Fingerprints H He Ne Kr

  29. Continuous spectrum is also called a “Blackbody Spectrum”

  30. Hot, low density gases generate emission line spectra. •  e.g. fluorescent lights

  31. Two stars orbiting one another. The diagram shows the orbital motion of one of the stars, and four different positions are marked (A, B, C, D). At which position is the light from the star redshifted? blueshifted? not shifted at all? a) A, C, B/D b) C, A, B/D c) B, D, A/C d) D, B, A/C D A C B

  32. The Earth’s atmosphere is opaque to the ________ part of the electromagnetic spectrum: • Visible • Infrared • X-Ray • All of the above • A and C are correct • B and C are correct

  33. Which of the following statements is true with regards to Blackbody radiation? • A blackbody emits more energy at longer wavelengths as it heats up. • A blackbody emits energy at all wavelengths • The shape of the blackbody spectrum depends on what the source is made of. • All of the above • None of the above

  34. 1 2 3 4 Which transitions were responsible for each of these absorption lines? a) A: 1-2 B: 2-4 C: 1-4 b) A: 1-4 B: 2-4 C: 1-2 c) A: 4-1 B: 4-2 C: 2-1

More Related