Chapter 4
Spectroscopy
Parts 1 & 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 and Examples of
“Exciting” Atoms (Quantum Leaps)
Aurora Borealis
Northern lights (Aurora’s) are one of nature's most beautiful
manifestations of the ability of electrons to jump between
quantum states
Northern Lights Video (3:57)
• Did you
ever
wonder
how we
know
what the
universe
is made
of?
Dust in black hole winds helped form early stars
The entire article is posted
near 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.
•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
Fireworks
Neon Signs
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.
American and 2 Japanese Physicists Share
2014 Nobel Prize for Work on LED Lights
LEDs
• LEDs, (Light emitting diodes), are found
in all kinds of devices.
• They form numbers on digital clocks,
transmit information from remote
controls, light up watches.
• Collected together, they form the
illuminated screens on cell phones and
television screens.
• Basically, LEDs are just tiny light bulbs
that fit easily into an electrical circuit.
But unlike ordinary incandescent bulbs,
they don't have a filament that will burn
out, and they don't get especially hot.
LEDs
• LED’s are illuminated solely by the movement
of electrons.
• The lifespan of an LED is impressive lasting
10 times as long as a fluorescent bulb and 100
times as long as an incandescent bulb.
• LED bulbs do not have toxic mercury as do
CFL’s.
• Due to low power requirements, it can be
powered by cheap local solar power. Thus
bringing the advantage of electrical devices to
places that lack electrical power grids.
• Currently upfront costs are higher than many
consumers which to pay but costs are
continuing to drop as technology improves.
• In the future, some of the most incredible uses of LEDs will
actually come from organic light emitting diodes, or OLEDs
which are flexible, allowing scientists to create bendable lights
and displays. (Imagine rolling your TV up like a poster and
carrying it with you anywhere).
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.
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: Flame Tests (27seconds)
..\..\..\..\Videos\Flame Tests.wmv
Homework
• Summarize the purpose and procedure for
the “Flame Test” Lab (Due tomorrow).
• Chapter 4 Worksheet 3 (Due Friday).
• Study Guide Chapter 4 (Due Friday).