In this video, we will be going through a few helpful tips and tricks for
completing lab one of Advanced Placement Chemistry Investigations. The goal of this
experiment is to determine the amount of food dye that's in a sports beverage. The
example we're going to use today is a sports beverage that contains blue one
food dye. We will be using a SpectroVis Plus Spectrophotometer connected to a
computer running Logger Pro software to begin our investigation. The first thing
that we will do is calibrate the SpectroVis Plus. To do so, we will use a
cuvette of distilled water, our solvent, place it in the SpectroVis Plus. And then
in Logger Pro, we will open the Experiment menu and choose Calibrate Spectrometer.
The calibration process takes about a minute and a half including warm-up. For
sake of time and because our SpectroVis Plus has been warmed up, we will skip the
warm-up, and then click on Finish Calibration to complete the process. Once
the process is complete, we will click Okay and proceed. We have a cuvette
containing a sample of our sports beverage that we will now place in the SpectroVis
Plus. In order to take measurements in an appropriate unit of measurement for this
experiment, we will again go to the Experiment menu in Logger Pro, and this
time choose Change Units, Spectrometer, % Transmittance. We're going to measure in
percent Transmittance. Having done that, we will now begin the data collection by
clicking the Collect button.
And notice that the process is complete rather quickly. Now we have a graph that
shows us percent transmittance versus wavelength of our sports beverage. An area
of the graph where the percent transmittance values are very low is a
region that is very helpful to identify for the analysis of samples to determine
the percent of blue one food dye. Notice one other thing on the graph before we
wrap up, and that is that there is a little strip of colored tape along the
x-axis. This is a color reference to show the visible spectrum as it's displayed and
measured on the SpectroVis Plus. In order to change that so that it becomes a full
set of readings and colors the entire graph, we will go to the File menu and
choose Preferences. And in the Preferences dialog box, we will remove the check next
to the comment that says "Graph Spectrum as Narrow Strip." If I remove the check
from that box and click Okay, now the full backdrop, the full-color display, appears
on the graph. And notice one other important thing. There is a black shadow
that goes along with the plotted points which can sometimes look like a second set
of data. It is there merely to highlight the readings so that they are easier to
see when the full backdrop is there. To see other videos for the use of the
SpectroVis Plus spectrometer in other experiments, please visit the Vernier
website.