Instant Light

 

Science Concept: Some exothermic reactions produce light energy instead of heat, and that chemiluminescence is a process by which the energy of a chemical reaction is converted into light.

Materials:

Directions:

Preparation of the "light crystals": Mix the dry ingredients thoroughly in the 400 mL beaker using the amounts listed above. Mix the luminol and the potassium ferricyanide together first and then add the Clorox 2. For the final mixing, pour the powder back and forth between two DRY beakers.

The dry mixture may be stored for months in a well sealed container.

Demo Procedure:

Fill the 400 mL beaker nearly full with distilled water.

Turn off light. If there is a problem with getting the room dark, then bring a small box that can be used to help create a dark space. Put the beaker inside of this.

Add some instant light crystals to water (1 tsp per every 200 mL water)

Observe the eerie blue light.

Variations:
1. Add 0.005 g of disodium fluorescein for a yellow green effect. Or 0.005 g of Rhodamine B for a red effect.

2. Put the water in a large graduated cylinder ( 250 mL or larger), sprinkle the light crystals on top and watch to streamers of light produced.

3. Put ice cubes in the water in the beaker and sprinkle the light crystals on top.

Introduction: Has anyone ever had one of those glow sticks from carnivals or the 4th of July? Did you ever wonder how they made that really cool glowing effect? Or how about what makes a fire fly glow in the summer time? Well, let me show you how!!!

Explanation: The oxidation of luminol is the best-known example of chemiluminescence. The chemiluminescence, or generation of light, actually occurs as luminol changes from an activated state to its ground state.

The reaction is initiated in the presence of an activator such as the ferricyanide ion and Clorox 2 which contains sodium perborate and sodium carbonate. The sodium perborate provides a source of hydrogen peroxide in a water solution. The hydrogen peroxide is the oxidizing agent for the luminol. Luminol gains two electrons in the process from the hydrogen peroxide which is converted to oxygen gas.

The luminol which first forms is in the so called "activated state" where the electrons occupy higher energy levels than normal. Quickly the electrons move from the activated state to the normal ground state and in the process this gives off light.

The excited electrons release energy in the form of light as they return to their ground state.

Safety: Do not breathe in fumes if heated, do not ingest any of the lab materials, wear goggles, and gloves.

Waste Disposal: Pour down sink with excess water.

Source: Flinn Scientific, Chem Fax, Instant Light, Pub. No. 629.00.