Tuesday, December 19, 2017

FIREWORK COLORS - How Firework Colors Work and Chemicals That Make Colors - Creating firework colors is a complex endeavor, requiring considerable art and application of physical science. Excluding propellants or special effects, the points of light ejected from fireworks, termed 'stars', generally require an oxygen-producer, fuel, binder (to keep everything where it needs to be), and color producer.

Firework Colors
 This fireworks display showcases a variety of colors.
Most colors come from the excitation of metal ions.
 
Chemistry of Firework Colors
How Firework Colors Work and Chemicals That Make Colors
ANNE MARIE HELMENSTINE, PH.D.
Creating firework colors is a complex endeavor, requiring considerable art and application of physical science.
Excluding propellants or special effects, the points of light ejected from fireworks, termed 'stars', generally require an oxygen-producer, fuel, binder (to keep everything where it needs to be), and color producer.
There are two main mechanisms of color production in fireworks, incandescence and luminescence.

INCANDESCENCE

Incandescence is light produced from heat.
Heat causes a substance to become hot and glow, initially emitting infrared, then red, orange, yellow, and white light as it becomes increasingly hotter.
When the temperature of a firework is controlled, the glow of components, such as charcoal, can be manipulated to be the desired color (temperature) at the proper time.
Metals, such as aluminum, magnesium, and titanium, burn very brightly and are useful for increasing the temperature of the firework.

LUMINESCENCE

Luminescence is light produced using energy sources other than heat.
Sometimes luminescence is called 'cold light', because it can occur at room temperature and cooler temperatures.
To produce luminescence, energy is absorbed by an electron of an atom or molecule, causing it to become excited, but unstable.
The energy is supplied by the heat of the burning firework.
When the electron returns to a lower energy state the energy is released in the form of a photon (light).
The energy of the photon determines its wavelength or color.
In some cases, the salts needed to produce the desired color are unstable.
Barium chloride (green) is unstable at room temperatures, so barium must be combined with a more stable compound (e.g., chlorinated rubber).
In this case, the chlorine is released in the heat of the burning of the pyrotechnic composition, to then form barium chloride and produce the green color.
Copper chloride (blue), on the other hand, is unstable at high temperatures, so the firework cannot get too hot, yet must be bright enough to be seen.

QUALITY OF FIREWORK INGREDIENTS

Pure colors require pure ingredients. Even trace amounts of sodium impurities (yellow-orange) are sufficient to overpower or alter other colors.
Careful formulation is required so that too much smoke or residue doesn't mask the color.
With fireworks, as with other things, cost often relates to quality.
Skill of the manufacturer and date the firework was produced greatly affect the final display (or lack thereof).

TABLE OF FIREWORK COLORANTS

Color
Compound
Red
strontium salts, lithium salts
lithium carbonate, Li
2CO3 = red
strontium carbonate, SrCO3 = bright red
Orange
calcium salts
calcium chloride, CaCl2
calcium sulfate, CaSO4·xH2O, where x = 0,2,3,5
Gold
incandescence of iron (with carbon), charcoal, or lampblack
Yellow
sodium compounds
sodium nitrate, NaNO3
cryolite, Na3AlF6
Electric White
white-hot metal, such as magnesium or aluminum
barium oxide, BaO
Green
barium compounds + chlorine producer
barium chloride, BaCl+ = bright green
Blue
copper compounds + chlorine producer
copper acetoarsenite (Paris Green), Cu
3As2O3Cu(C2H3O2)2 = blue
copper (I) chloride, CuCl = turquoise blue
Purple
mixture of strontium (red) and copper (blue) compounds
Silver
burning aluminum, titanium, or magnesium powder or flakes

SEQUENCE OF EVENTS

Just packing colorant chemicals into an explosive charge would produce an unsatisfying firework!
There's a sequence of events leading to a beautiful, colorful display.
Lighting the fuse ignites the lift charge, which propels the firework into the sky.
The lift charge can be black powder or one of the modern propellants.
This charge burns in a confined space, pushing itself upward as hot gas is forced through a narrow opening.
The fuse continues to burn on a time delay to reach the interior of the shell.
The shell is packed with stars that contain packets of metal salts and combustible material.
When the fuse reaches the star, the firework is high above the crowd.
The star blows apart, forming glowing colors through a combination of incandescent heat and emission luminescence.

 

ANNE MARIE HELMENSTINE, PH.D. is an author and consultant with a broad scientific and medical background.
EXPERIENCE
Anne has taught chemistry, biology, and physics at the high school, college, and graduate level. In her doctoral work, Anne developed ultra-sensitive chemical detection and medical diagnostic tests. She has worked abstracting/indexing diverse scientific literature for the Department of Energy. She presently works as a freelance writer and scientific consultant. She enjoys adapting lab-based science projects so that they can be performed safely at home.
EDUCATION
Dr. Helmenstine has bachelor of arts degrees in physics and mathematics with a minor in chemistry from Hastings College in Nebraska and a doctorate of philosophy in biomedical sciences from the University of Tennessee at Knoxville.
ANNE MARIE HELMENSTINE, PH.D.
Chemistry is part of everyone's life, from cooking and cleaning to the latest computer chip technology and vaccine development. It doesn't have to be intimidating and it doesn't have to be hard to understand.
You can read more about Anne's current and past work on her Google Profile: Anne Helmenstine. Find Anne's printable periodic tables and science projects at Science Notes.
.
Multi-Media Filter, Highly-Activated Carbon Filter,
Zeolite-Process Water Softener With Brine Tank,
Fiberglass Ballast-Type Pressure Tank
(fully automatic backwash & regeneration)
.
PURICARE 
INDUSTRIAL 
ENTERPRISES 
Water 
Treatment 
Systems
.
...

Aganan, Pavia, Iloilo, Philippines
...

CLICK HERE . . . to view company profile . . .
Reverse Osmosis with Steel Tank 
& Cartridge Pre-Filters

Submersible Pumps

Tachmina Solenoid-Driven
Chemical Metering Pump
- ensures regulated dosing
of chlorine into water system
without human intervention











No comments:

Post a Comment