Date: Tue, 12 Mar 2002 08:32:58 -0500

Author: Wolfgang Rueckner

Subject: Re: spectra


Tom -- you can obtain a nice and clear absorption spectrum as
follows: Project a continuous white-light spectrum onto a screen
using a slide projector with the slit-slide focused on a distant
screen. The prism is placed a foot or so in front of the slide
projector, giving you enough room for a bunsen burner to be put
between the projector and prism. Toss some baking soda into the
flame to turn it brilliant yellow (sodium) and see the sodium
absorption lines on the screen at the same time. Your slit should be
fairly narrow if you wish to see a narrow absorption line. Wolfgang

>Check out the following link. It gives a nice simulated spectrum for many
>of the elements as well as showing the electron orbits.
>An interesting application is to have students look at a fluorescent light
>and see if they can find the spectrum lines for mercury which is actually
>used to excite the phosphors in the tube.
>Also try putting a glass rod in a bunsen burner flame. The bright yellow is
>from the sodium used in the glass. Compare that to a regular "yellow" flame
>from a candle and students will see that a candle flame is continuous but
>the sodium is very distinctly an emission spectrum.
>You can also spray salt solutions into a bunsen burner flame to show
>spectra. Salt will give sodium lines, but strontium, lithium, copper,
>potassium, and others are nice to look at.
>Also try exciting the gas in an incandescent bulb using a Tesla coil to let
>you discover what it is (argon typically).
>This is always a favorite topic for me in astronomy class. I'm still
>seeking a nice clear absorption spectrum. So far I've used glass and
>plastic and solutions for absorption, but nothing with the sharp lines that
>you'd get from a gas.
>Tom Gill
>Central Columbia HS
>Bloomsburg, PA
>----- Original Message -----
>From: "Anthony Lapinski"
>Sent: Monday, March 11, 2002 11:19 AM
>Subject: spectra
>> I show spectra of gas tubes in my high school astronomy class. We have
>> argon, helium, hydrogen, krypton, mercury vapor, neon, and water vapor. I
>> wish to purchase a few more (Flinn, p. 286), but I don't know the spectra
>> of these gases:
>> air
>> bromine vapor
>> carbon dioxide
>> chlorine gas
>> iodine vapor
>> nitrogen gas
>> oxygen gas
>> xenon
>> Has anyone ever seen these spectra? How do they appear? I'm looking for
>> ones with nice colors, clear lines, etc. Thanks!