Introductory Colorimetry
Monitor the progress of a chemical reaction by measuring the amount of colored light absorbed by the solution as the reaction progresses.
PASPORT Oxygen Gas Sensor (PS-2121)
ScienceWorkshop Colorimeter
(CI-6747)
Lab Summary
Monitor the progress of a chemical reaction by measuring the amount of colored light absorbed by the solution as the reaction progresses.
A colorimeter measures the amount of colored light absorbed by or transmitted through a solution. The amount of light, and what color light, is absorbed or transmitted depends on properties of the solution, including the concentration of particles in it. Therefore, when a solution is analyzed with a colorimeter, properties of the solution such as its concentration can be determined.
Grape juice will be mixed with other liquids in this activity to determine if a chemical reaction occurs. Typically, a dark-colored liquid such as grape juice will absorb a greater amount of light energy (i.e., less light will be transmitted through it) than a light-colored liquid with similar properties. If a chemical reaction occurs and changes the color of the solution, it would be reasonable to expect that the solution's ability to absorb light would also change. This method of analysis can be particularly useful when a subtle color change (one that is difficult to observe or quantify with the human eye) occurs as a result of a reaction.
Grape juice will be tested with water, household bleach (a dilute aqueous solution of sodium hypochlorite), and a household solution of hydrogen peroxide.
Hypothesize: Will the grape juice react with water, bleach, and/or the hydrogen peroxide? In which case will the reaction proceed fastest? How will the solution's ability to absorb colored light change as a reaction takes place?
Published: May 2003
Downloads
- Introductory Colorimetry - PASPORT (23 KB, .zip)
Includes experiment setup, procedures and Datastudio file
- Introductory Colorimetry - ScienceWorkshop (23 KB, .zip)
Includes experiment setup, procedures and Datastudio file
Here's What You Need
U.S. Educator prices shown.
Probeware (PASPORT Systems)
Xplorer GLX (PS-2002) - $349
The Xplorer GLX is a data collection, graphing, and analysis tool designed for science students and educators.
PASPORT Colorimeter Sensor (PS-2121) - $119
Our PASPORT Colorimeter records all 4 wavelengths simultaneously--no need to guess at wavelength to get a quality measurement.
Probeware (ScienceWorkshop Systems)
750 Interface, USB (CI-7650) - $679
The 750 Interface allows students to measure force, temperature, pressure, angular velocity, acceleration, current, and magnetic field with a built-in function generator and oscilloscope mode.
Colorimeter (CI-6747) - $225
Allows absorbance & transmittance measurement in four wavelengths.
Other Materials
- 4 cuvettes with caps (packaged with the Colorimeter Sensor)
- Grape juice, approx. 20 mL
- Household bleach, approx. 2 mL
- Hydrogen peroxide solution, approx. 2 mL
- 10-mL graduated cylinder
- Medicine dropper or disposable pipettes
- Distilled water
- Marking pen or labels for cuvette caps
