Chemistry Enrichment Resources
Church Resources
Maple Syrup & Oil Drop
Church Resources
Maple Syrup & Oil Drop
Minerals in Maple Syrup.
Maple syrup is a concentrated sap from the sugar maple tree which grows principally in Maine, New Hampshire, Vermont, Oregon, Quebec, and British Columbia. As may be expected, the sap, and thus the syrup, contains small amounts of various metals. In this experiment, the concentrations of selected metals are analyzed by Atomic Absorption Spectroscopy. For each metal, the instrument must be standardized before analyzing an aqueous solution of the syrup. From the data, the concentration of each metal in the syrup can be calculated. The PowerPoint demonstrates the instrument and the analysis of one metal. A separate file is provided with the data for four other metals (and answers). Click here for the file. Also provided is a file showing the process for planning the experiment using one metal as an example. Click here for the file.
Maple syrup is a concentrated sap from the sugar maple tree which grows principally in Maine, New Hampshire, Vermont, Oregon, Quebec, and British Columbia. As may be expected, the sap, and thus the syrup, contains small amounts of various metals. In this experiment, the concentrations of selected metals are analyzed by Atomic Absorption Spectroscopy. For each metal, the instrument must be standardized before analyzing an aqueous solution of the syrup. From the data, the concentration of each metal in the syrup can be calculated. The PowerPoint demonstrates the instrument and the analysis of one metal. A separate file is provided with the data for four other metals (and answers). Click here for the file. Also provided is a file showing the process for planning the experiment using one metal as an example. Click here for the file.
Students will learn: (1) how an Atomic
Absorption Spectrometer works, (2) how to work with concentration units of parts per million, (3) recommended Daily Value levels in
a person's diet for metals, (4) how an AA experiment is planned.
The PowerPoint is available for use as is or to be modified as desired.
Millikan's Oil Drop Experiment to Determine the Charge on the Electron
In the early 1900s, fundamental
values such as Avagadro's Number, charge on the alpha particle, mass of fundamental particles, etc. were being determined. An
accurate value of the charge on an electron was needed in order to be able to complete the required set. Robert Millikan modified
an existing apparatus (using oil drops rather than water drops) and developed the other necessary techniques and mathematical relationships (such
as the rate of fall of oil drops in air) to successfully report an accurate value of the charge.
Students
will learn: (1) how a 1909 apparatus works, (2) that negative particles are attracted to a cathode, (3) how varying the potential
can reverse the fall of charged particles due to gravity, (4) how to indirectly calculate a quantity that cannot be measured directly,
and (5) how the appearance of fraud can ruin a reputation.
Suggested class experiment: Prepare 40 to 50 envelopes
containing varying numbers of 3 x 5 file cards. Suggested number of cards in an envelope should be from 1 to 12 with some quantities
(like 5 and 8) missing and at least one envelope with only 1 card. Have the class weigh these to +/- 0.1 g then follow the calculation
procedure given in the PowerPoint and in the Narrative file. Also, a discussion of scientific misconduct would be appropriate.
The hydrogen atom shown on the previous page was taken by photoionization and confirms the theoretical calculations that previously
had proposed this same configuration. Phys. Rev. Lett. 2013, 110, 213001-1-213001-5.
For a complete set of
data with narrative about the calculation procedure, click here.
The PowerPoint is available for use as is
or to be modified as desired.
