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Supernova Chemistry Teacher Notes |
PRE-LAB
- Students do not have to have an intimate
knowledge of quantum mechanics to understand the
basic principles of spectroscopy. Basically, they
need to understand that every type of atom has a
unique electron configuration, that the position of
an electron affects how much energy it has, and
that this causes different substances to interact
with light in different ways. An understanding of
the Bohr model of the atom should suffice. Make
sure that they understand the incredible number of
ways that spectroscopy is used: X-ray spectroscopy,
Atomic Emission spectroscopy, Infrared
spectroscopy, Nuclear Magnetic Resonance imaging
(NMR), and UV spectroscopy. Most of the components
in the Hubble Space Telescope are related to
spectroscopic analysis.
- There are ten (10) total stations, so groups
should be assigned appropriately.
- Students will have 4 minutes per station if the
data collection is completed in one day. If more
time is needed, two days for data collection can be
allowed.
- The chemical light sticks will need to be
changed when they begin to grow dim.
- Remember that about 1 out of 5 boys experience
some degree of color-blindness. Usually, they
should be able to see the bright lines, but they
might misinterpret the color or think it's "white"
light. Each pair of students should double-check
each other, and avoid boy-boy pairs as much as
possible. Many boys are unaware by this age that
they may have a problem with particular colors, so
be sensitive to the fact that some may "discover"
their color-blindness during this activity.
DURING LAB
- Caution students strongly about the need to
avoid touching the gas tubes or the electrical
power units. There is a very real chance that they
could be burned or electrocuted if they directly
touch the tubes. Make sure that the units are
plugged into the GFI outlets.
- Students need to keep safety glasses on
throughout the activity. The gas tubes get very
hot, and they can burst. Use a fluorescent light
strip in the lab or an adjacent area as the
fluorescent source.
- For each pair or group, let one student observe
the spectrum through the Spectrometer and call out
the "bright line" wavelengths to their partner. The
partner should double-check the line positions, and
then the two of them should agree before they use
the colored pencils to shade in the areas of their
spectrum. They should change stations every 4
minutes in order to complete the activity in a
period.
- Some of the tubes will produce just line
spectra, but most will have some degree of at least
one part of the continual spectrum. This is because
of the limited resolution of the diffraction
grating used in the Spectrometers.
POST-LAB
- Talk to students about the many different ways
in which spectroscopy is used by modern scientists.
Spectrometers of various forms represent the most
important single group of lab instruments in the
research lab today.
- Allow students to compare their spectra for
different tubes with other groups, and encourage
them to discuss the differences and similarities.
Ask students to draw relationships between what
they said about light after the engagement activity
and what they discovered about light during the
laboratory activity.
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