Flame Test – Colorful Elements

Burning metals reveal themselves from unexpected, awesome colors in a simple flame test.

Blue, orange, and yellow flames are pretty common. What about green or purple flames? When you’re used to the everyday colors of flames, colorful changes like these can be pretty cool. These surprising colors are the result of the presence of specific metals in the burning material. Here are a couple of household materials that contain metals that are easily seen and identifiable in a Flame Test.

Experiment Materials

  • 2 Popsicle sticks
  • Boric acid
  • Cream of tartar
  • Small glass dish for each powder tested
  • Flame source
  • Small cup of water
  • Container of water to douse the flame
  • Adult supervision

Experiment Videos

Experiment

1

Pour a little powder to test into each small dish. Dip one end of a popsicle stick into the water to moisten it.

2

Dip the wetted popsicle stick into the boric acid. Coat the tip of the stick completely.

3

It helps to dim the lights in your lab so the colors are easier to see. Light the flame and place the boric acid-covered popsicle stick into the flame. Move the flame under the stick to find the best color. Look for an unexpected color in portions of the flame. An assistant could take a picture of it. Douse the flame in the large container of water.

4

Dip the end of another popsicle stick in water. Coat the tip with the cream of tartar.

5

Follow the procedure in Step 3 for this test. You may see some surprising flashes. This color is harder to see but it’s there.

How Does It Work

This activity is called a flame test and it’s a real procedure used in labs. Its purpose is to identify specific elements in a material. When the boric acid was in the flame, you probably notice a bright green portion of the flame. You may have seen it only briefly but it was there. The green color denotes the presence of the element boron (B) which you’d expect in boric acid. The cream of tartar yielded a purple-colored flame. Purple is associated with the presence of potassium (K). That’s because cream of tartar is a potassium salt.

These element-specific colors are catalogued in an emission spectrum. The emission spectral color of an element occurs when certain electrons in an atom are excited to a higher energy level and then make a transition from that level to their normal energy state. In that downward transition, energy is released as a photon of light at a specific wavelength of color. The hiding element is revealed by color!

Colors of Other Elements

As Arsenic Blue
B Boron Bright green
Ba Barium Pale/Yellow-green
Ca Calcium Orange-red
Cu (I) Copper (I) Blue
Cu (II) Copper (II) non-halide Green
Cu (II) Copper (II) halide Blue-green
Fe Iron Gold
In Indium Blue
K Potassium Light purple to red
Li Lithium Deep pink to dark red
Mg Magnesium Bright white
Mn (II) Manganese (II) Yellow-green
Mo Molybdenum Yellow-green
Na Sodium Bright yellow
P Phosphorous Pale blue-green
Pb Lead Blue
Rb Rubidium Red/Purple-red
Sb Antimony Pale green
Se Selenium Bright blue
Sr Strontium Crimson
Te Tellurium Pale green
Tl Thallium Bright green
Zn Zinc Blue-green to pale green