Chapter 4
The Bohr Model of the Atom
Part 2
Quantum Leaps
• A quantum leap is a change of an
electron from one energy state to another
within an atom.
• Quantum leaps cause the absorption and
emission of electromagnetic radiation in
which “excited” atoms release small
packets of electromagnetic energy called
photons.
Some Uses of “Exciting” Atoms
(Quantum Leaps)
•Spectroscopy is the study of the energy which is given off and
absorbed when atoms go from the ground state to the excited
state and back again.
•Spectroscopy is often used in chemistry for the identification of
substances, through the spectrum absorbed or emitted.
Spectroscope
Dust in black hole winds helped form early stars
The entire article is posted on
the door of the classroom if
you would like to read more.
Astronomers have taken a baby step in trying to answer the cosmic question of where we come from.
Planets and much on them, including humans, come from dust — mostly from dying stars. But where did the
dust that helped form those early stars come from?
A NASA telescope may have spotted one of the answers. It's in the wind bursting out of super-massive black
holes.
The Spitzer Space Telescope identified large quantities of freshly made space dust in a quasar about 8 billion
light years from here.
Astronomers used the telescope to break down the wavelengths of light in the quasar to figure out what was
in the space dust. They found signs of glass, sand, crystal, marble, rubies and sapphires, said Ciska
Markwick-Kemper of the University of Manchester in England. She is the lead author of a study that will be
published later this month in Astrophysical Journal Letters.
Fireworks
Light Sources – Mercury
Mercury Vapor Lamp
CFL’s
The average rated life of a CFL is
between 8 and 15 times that of
incandescents. CFLs typically have
a rated lifespan of between 6,000
and 15,000 hours, whereas
incandescent lamps are usually
manufactured to have a lifespan of
750 hours or 1,000 hours.
• Spectrum of a CFL bulb. The
camera had a diffraction
grating in front of the lens. The
discrete images are produced
by the different colors in the
light, a line spectrum. An
incandescent lamp would
instead have a continuous
band of color.
Neon Signs
Lasers
• You'll find them in
everything from CD
players to dental drills
to high-speed metal
cutting machines to
measuring systems.
Tattoo removal, hair
replacement, eye
surgery -- they all use
lasers.
What else can lasers be used for?
Sharks
I want sharks with laser beams
attached to their heads.
Flame Tests
Flame Tests
• A flame test is a procedure used in chemistry to
detect the presence of certain metal ions based on
each element's characteristic emission spectrum.
Video: Molecular Fingerprints
Student Worksheet
Use Windows Media Player
Homework
 Summarize the purpose and procedure for
the “Flame Test” Lab.
 Continue to work on Chapter 4 Worksheet 3.
 Study Guide Chapter 4 (2 pages) is due
tomorrow.