Calculate the Energy!
Days Needed less than 1
Grade level 9 - 12
Students will review what has been
learned so far about the basic structure of an atom.
Students will then calculate the energy differences in different
energy states of the Bohr atom of Hydrogen. They will then compare
these energy levels with observed Hydrogen lines in a laboratory spectrum.
Science and Math Standards
|Content Standard 2:
- Mathematics as Communications
|Content Standard A:
- Evidence, models, and explanation
|Content Standard 4:
- Mathematics as Connections
|Content Standard C:|
- Structure of atoms
Math Students should be familiar with basic algebra.
Science Students should understand the structure of
atoms and the relationship between energy and light, and how atoms emit
Students should have read the background sections on the Properties of Light and
Atoms and Light Energy.
We can use tools like the periodic table of elements
to figure out exactly how many protons, neutrons, and electrons at atom has.
Understanding the structure and function of an atom is very important in
understanding spectroscopy. Spectroscopy is one of the most useful
tools for unlocking the mysteries of supernovae and their remnants.
Edible Subatomic Particles -
large plastic easter eggs, enough for one per student, or one per group.
gumballs or m&ms of two different colors
ping pong balls (same amount as easter eggs)
1. A large plastic egg (atom) is given, one per person - each egg
contains a split ping pong ball (nucleus) with a set number of either
gumballs or m&m type candies (neutrons and protons) inside. Be sure
to use different colors for protons and neutrons. Put smaller hard
candy (like tic tacs, for instance) in the egg, but so they can move
freely around the ping pong ball. They will be the electrons. Make
sure there are the same amount of protons as electrons (unless you
want an ionized atom!) You may want to give each student an "atom" of
a different "element" by varying the number of sub-atomic particles in
each students egg.
2. Without opening the egg, and using the scientific method, have
the students determine the components within: number, size,
movement, weight/mass, sound.
3. Have the students open the eggs - now report on the contents
specifically as to number and size only. Can the student deduce what
element they have an atom of? Make sure to point out that the electrons
are not in perfect orbits around the nucleus. Like real electrons, they
form a sort of electron cloud. Now is a good time to bring in
information about the quantum mechanical nature of the atom.
For example, originally, each electron orbital was pictured as having a
specific radius, much like a planetary orbit in the solar system. However,
the modern view
is not so simple. Though each orbital does have a precise energy, the
electron is now envisioned as being smeared out in an "electron cloud"
surrounding the nucleus.
Adapted from a lesson plan by Miriam Meade,
In the background section on "Atoms and Light Energy", the students should have
learned that there are many energy states within an atom. The class is now
going to calculate the energies differences between some of the different
levels the atom. This will tie directly in to the concept of a spectrum.
Print out the Student
Worksheet for the class. Have students eat remains of atom while completing
on the worksheet.
Students should show calculations of energy levels. These calculations and
answers to the questions on the Student Handout, as well as the closure
excercise, provide material for assessing the students' understanding of
the concept that energy transitions lead to emission of observed light at
Students should write a three minute paper describing how this excercise
explains line emission from atoms such as hydrogen.
Any number of materials could be substituted to create the "atoms":
corn kernals for protons, navy beans for neutrons, alfalfa seeds
poppy seeds or cake decorating sprinkles or small beads for electrons,
etc. If plastic eggs are out of season, a clear plastic ball that
come in two halves (available at craft or fabric stores) can be used.
Students can also weigh the individual constituents before the atom
is assembled. They should see that most of the mass of the atom is
made up of the protons and neutrons.
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