A mixture of solutions first glows red and then amidst vigorous frothing and evolution of heat, an eerie blue glow appears.
- Oxidation reactions
Formaldehyde, CH2O, 37%, 10 mL*
Fountain of Light solution, 40 mL*
Hydrogen peroxide, H2O2, 30%, 25 mL*
Potassium carbonate, K2CO3, 25.0 g*
Graduated cylinder, 10-mL
Graduated cylinder, 100-mL
Graduated cylinder, 250-mL
Gloves (plastic or rubber)
Shallow pan or 2-L beaker to catch overflow
*Materials included in kit.
Formaldehyde is an alleged carcinogen and a strong irritant. Avoid inhalation of vapors and skin contact. Hydrogen peroxide is a very strong oxidant. Avoid direct skin contact. Wear chemical-resistant gloves, chemical splash goggles and a chemical-resistant apron while preparing and performing this demonstration. A fume hood or well ventilated area is a must. Flinn strongly recommends against the use of glyoxol or any other formaldehyde alternative as a substitute to formaldehyde in this demonstration. Violent reactions can result. Please review current Safety Data Sheets for additional safety, handling and disposal information.
Please consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. The resulting solution may be disposed of according to Flinn Suggested Disposal Method #26b.
- In the hood or a well ventilated area, measure 40 mL of the Fountain of Light solution into a 250-mL beaker.
- Add 25.0 g potassium carbonate. Stir to dissolve.
- Add 10.0 mL of 37% formaldehyde. Stir. Transfer solution to a 250-mL graduated cylinder.
- Place the cylinder in a 2-L beaker or shallow pan. Note: This demonstration is very messy; clear the surrounding area.
- To perform the demonstration, turn off the lights. With the room completely darkened, add 25 mL of 30% hydrogen peroxide. Do not stir. Stand back and observe the incredible two-color chemiluminescense!
- The mixture glows dull red for a few seconds, turns bright blue and then foams vigorously. This is an exothermic reaction.
- The Fountain of Light solution contains 0.8 g sodium hydroxide, 0.005 g luminol and 1.0 g pyrogallol (pyrogallic acid) in each 40 mL of distilled water.
- Room must be completely dark.
- Dull red is not visible unless room is completely dark and only appears for 1–2 seconds.
Correlation to Next Generation Science Standards (NGSS)†
Science & Engineering Practices
Developing and using models
Constructing explanations and designing solutions
Engaging in argument from evidence
Disciplinary Core Ideas
MS-PS1.A: Structure and Properties of Matter
HS-PS1.A: Structure and Properties of Matter
HS-PS1.B: Chemical Reactions
HS-PS3.A: Definitions of Energy
HS-PS3.B: Conservation of Energy and Energy Transfer
HS-PS3.D: Energy in Chemical Processes
Cause and effect
Systems and system models
Energy and matter
HS-PS1-1. Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms.
HS-PS1-2. Construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
HS-PS4-3. Evaluate the claims, evidence, and reasoning behind the idea that electromagnetic radiation can be described either by a wave model or a particle model, and that for some situations one model is more useful than the other.
Answers to Questions
- Describe what happened in this demonstration.
A solution was added to another solution in a beaker. The beaker solution began to glow a dull red. Then, after a few seconds, it glowed a bright blue and produced a great deal of foaming.
- Oxidation is necessary for luminol to luminesce. The chemicals used in this experiment were 37% formaldehyde, 30% hydrogen peroxide and potassium carbonate. Which of these do you think served as the oxidizing agent?
Hydrogen peroxide was the oxidizing agent in this demonstration.
- What caused the frothing in the beaker after the hydrogen peroxide was added?
As the hydrogen peroxide decomposed and oxidized, it produced carbon dioxide, hydrogen and oxygen, which were responsible for the foaming.
- In chemiluminescence, a molecule in an “excited” state (i.e., electrons are at a high energy level) is produced. The electrons in the molecule then must return to their stable state (i.e., lower energy level). Explain how this is linked to the production of light.
When an electron drops to a lower energy level, energy must be released. This energy is released in the form of light.
Chemical luminescence (chemiluminescence) is a process by which the energy of a chemical reaction is converted into light energy. The generation of light is typically associated with thermal reactions such as incandescence or the study of atomic spectra. In cases of chemiluminescence, light is actually a product of the reaction taking place.
Light is produced when electrons drop from an excited or high energy level to a stable, or lower energy level. The wavelength of the light produced is directly related to the energy difference between the two energy levels. Because this is a distinct energy difference, only specific wavelengths are produced by a particular element or compound.
In chemiluminscence, a reaction produces a molecule that is in an excited state. As the electrons in this molecule return to their ground state, energy is released in the form of light, usually a characteristic light based on the energy difference.
In this demonstration, two different chemiluminescent processes are occurring. The initial red glow is due to singlet oxygen that is produced during the oxidation of pyrogallol and formaldehyde by the alkaline hydrogen peroxide. Singlet oxygen is oxygen in an excited state due to one of its electrons being in a higher-energy orbital. As this electron drops back down to its ground state, red light is emitted.
The blue glow is caused by the subsequent oxidation of luminol. This reaction does not begin until the red glow from the singlet oxygen has disappeared, and is accompanied by significant frothing. This suggests that the singlet oxygen is not responsible for the oxidation but rather it is caused by some subsequent reaction intermediate. The frothing is caused by production of CO2, H2 and O2 from the initial hydrogen peroxide decomposition and oxidations.
Shakhashiri, B. Z. Chemical Demonstrations: A Handbook for Teachers in Chemistry; University of Wisconsin: Madison; 1983; Vol. 1, pp 175–179.