Colored flames

Distinguish elements by their flame color!

10 minutes



  • Conduct the experiment on the plastic tray.
  • Remove protective gloves before lighting the splint (step 3).
  • Keep flammable objects and hair away from flame.
General safety rules
  • Do not allow chemicals to come into contact with the eyes or mouth.
  • Keep young children, animals and those not wearing eye protection away from the experimental area.
  • Store this experimental set out of reach of children under 12 years of age.
  • Clean all equipment after use.
  • Make sure that all containers are fully closed and properly stored after use.
  • Ensure that all empty containers are disposed of properly.
  • Do not use any equipment which has not been supplied with the set or recommended in the instructions for use.
  • Do not replace foodstuffs in original container. Dispose of immediately.
General first aid information
  • In case of eye contact: Wash out eye with plenty of water, holding eye open if necessary. Seek immediate medical advice.
  • If swallowed: Wash out mouth with water, drink some fresh water. Do not induce vomiting. Seek immediate medical advice.
  • In case of inhalation: Remove person to fresh air.
  • In case of skin contact and burns: Wash affected area with plenty of water for at least 10 minutes.
  • In case of doubt, seek medical advice without delay. Take the chemical and its container with you.
  • In case of injury always seek medical advice.
Advice for supervising adults
  • The incorrect use of chemicals can cause injury and damage to health. Only carry out those experiments which are listed in the instructions.
  • This experimental set is for use only by children over 12 years.
  • Because children’s abilities vary so much, even within age groups, supervising adults should exercise discretion as to which experiments are suitable and safe for them. The instructions should enable supervisors to assess any experiment to establish its suitability for a particular child.
  • The supervising adult should discuss the warnings and safety information with the child or children before commencing the experiments. Particular attention should be paid to the safe handling of acids, alkalis and flammable liquids.
  • The area surrounding the experiment should be kept clear of any obstructions and away from the storage of food. It should be well lit and ventilated and close to a water supply. A solid table with a heat resistant top should be provided
  • Substances in non-reclosable packaging should be used up (completely) during the course of one experiment, i.e. after opening the package.

FAQ and troubleshooting

I can’t insert the bottle nozzle.

Try using another bottle nozzle. It should fit snugly in the bottle. Of course, you can always ask an adult for help.

Can I use ordinary foil for this experiment?

If you look closely, you’ll notice that the foil from the set is much thicker than ordinary foil. Unfortunately, this makes it difficult to replace with foil from another source. We strongly recommend using the foil we provide – it should suffice to repeat the experiment several times.

I can't get the solid fuel out of the bottle.

Use a wooden stick from the set to mix the solid fuel well. This should help break up any lumps and allow you to measure the solid fuel as intended.

How should I pour the metal powders on the flame?

Point the bottle nozzle toward the flame at about a 30-40 degree angle. Gently tap the bottle to dislodge some powder into the flame. If this doesn’t seem to work, tilt the bottle at a steeper angle and tap slightly harder.

I have some copper and zinc powder left over after the experiment. Is there any way to reseal the bottles so I can repeat the experiment later?

The bottle nozzles are very secure, so it will be difficult to pull them out. If you would like to repeat the experiment in the near future, you can just carefully leave the bottles in an upright position. If this isn’t doable, you can try to find suitable caps from other sets. You can also place the bottle and the nozzle in a resealable plastic bag. Finally, examine the caps from the bottles with powders. If you pull out the white round plugs, these caps can be used for the bottles with nozzles.

Step-by-step instructions

Prepare some powdered zinc Zn and copper Cu.


Prepare some solid fuel.


Pour some of each metal powder over the flame and see what happens.



Dispose of solid waste together with household garbage.

Scientific description

When talking about metals, you likely think of solid substances with silvery lusters, used to build towering architectural structures and cars. Not about tinting a flame green and whitish-blue using copper Cu and zinc Zn powders, respectively. So what’s up with that? The Cu and Zn powders react with oxygen in the extreme heat of the flame to yield Cu2+ and Zn2+ ions. These ions take a lot of heat energy from the flame and release it in the form of light!

Chemists use this effect to determine which metals are present in a sample. But this requires careful study of a flame using special equipment—a spectrometer. This yields a characteristic ID for the element, known as its emission spectrum, which looks rather like a colorful barcode.

The green flame you see is due to copper's emission spectrum. Interestingly, several elements were discovered thanks to, and named for, their most intensive spectral line. For example, indium was named for its indigo-colored line, caesium for its blue line (Latin caesius—sky-blue), and rubidium for its bright red line (Latin rubidus—deep red).

That’s interesting!

More about flame colorants

Some flames are almost invisible, while others shine brightly. For example, hydrogen burns with an almost completely colorless flame, as does pure alcohol; meanwhile, an ordinary candle or fire burns with a bright glow. Ultimately, the brightness of any flame depends on the presence of red-hot solid particles in it.

Carbon-based fuels release tiny particles of carbon, which accumulate more rapidly than they burn. The flame of a gas burner, kerosene lamp, or candle shines due to the glow of these same carbon particles. A weakly-glowing flame can brighten if enriched with carbon or other substances.

Certain metals and metal salts can be added to flames to tint them different colors. The high temperature of the flame makes it possible for individual metal ions  in these metals and compounds to become "overheated" so some of their electrons can enter a higher energy state. When these electrons return to their original, “unexcited” state, they emit light of a certain wavelength. This results in differently-colored flames. For example:

Orange flame – sodium chloride

Red flame – calcium chloride

Light-violet flame – potassium chloride

Turquoise flame – copper sulfate

Blue flame – copper chloride or selenium

Light-green flame – borax

Pink flame – strontium chloride

Scarlet flame – lithium chloride

It’s worth noting that the flame’s color depends on the metal cation; the salt’s anion has practically no influence whatsoever. This characteristic of certain metals is also exploited to produce colored lights — in pyrotechnics, for instance.