Boric acid combined with a few readily-available materials will create colored flame effects to spice up your Halloween pumpkin.

Flaming pumpkin

 

SUPPLIES

Read the warnings/safety precautions sections on each product’s label before beginning this experiment.

  • A few real, carved pumpkins (do not use not plastic pumpkins)
  • A small, heat-safe, non-flammable, fireproof container (Lodge makes several small cast iron servers) or aluminum foil
  • Boric acid
  • A tablespoon (for measuring) and a metal, long-handled utensil (for mixing)
  • HEET gas-line antifreeze, which you can find in an auto parts store (be sure to use HEET, which contains methanol, and not ISO-HEET, which contains isopropyl alcohol and will not work)
  • Hand-sanitizer that contains ethyl alcohol, such as Germ-X
  • A long-handled grill lighter or several long-stick matches

SAFETY

Work Environment—This Mixture is Highly Flammable

  • Do not work indoors. Work outdoors. Fumes created by this experiment are highly flammable.
  • Work on a non-flammable surface, such as a concrete driveway, at least 4’ away from any wooden structures (deck, tree, house, etc.) and dry ground cover.
  • Have a functioning ABC fire extinguisher nearby and ready to use, in case the fire spreads. Water is insufficient as it will only spread the fire.

Protective Equipment

  • Wear non-fuzzy, non-synthetic clothing such as cotton or wool. Natural fibers may be flammable, but will not melt to your skin like synthetics.
  • Laboratory style (e.g., nitrile, neoprene, latex) gloves and safety glasses or goggles are recommended when handling the chemicals.

Safe Practices

  • Do not leave an ignition source or flaming pumpkin unattended.
  • Do not let any animals (or children) eat the pumpkin afterwards as there will be boric acid residue left behind.
  • Wash your hands thoroughly after handling the chemicals. Remove and replace any clothing which may have gotten splashed.
  • Do not smoke while performing this experiment.
  • Do not perform this experiment without adult supervision.
  • Allow extinguished pumpkins to cool completely before handling.

DIRECTIONS

Use boric acid and HEET to create vivid green flames:

  1. Carve a pumpkin.
  2. Place a heat-safe, non-flammable, fireproof container in the bottom of the pumpkin (dedicate this container to chemical use only; do not use it to prepare, cook or serve food afterward). Lining the inside of your pumpkin with a couple of layers of aluminum foil will work in a pinch.
  3. Put on safety glasses and protective laboratory-style gloves. Be sure to work outdoors in a well-ventilated area, as the mixture will produce flammable fumes. Have an ABC fire extinguisher nearby and ready to use.
  4. Sprinkle a tablespoon of boric acid into the heat-safe container.
  5. Carefully pour two or three tablespoons of HEET into the heat-safe container with the boric acid.
  6. Gently stir the ingredients together for 30 seconds, being careful not to inhale the fumes or splash/spill the mixture. Remove and replace any clothing that has been splashed by the mixture.
  7. Using a long-handled grill lighter or a long-stick match (not a cigarette-style lighter or typical short match), touch the flame to the surface of the mixture until ignited; if you simply drop a match into the heat-safe container, you will see yellow and orange fire first, and the green flames will not be as vivid.

You can also use boric acid to create rainbow-colored flames on your Halloween pumpkin:

  1. Put on safety glasses and protective laboratory-style gloves. Be sure to work outdoors in a well-ventilated area. Have an ABC fire extinguisher nearby and ready to use.
  2. Use your gloved hands to smear hand sanitizer generously all over the inside and outside of a carved, real—not plastic—pumpkin.
  3. Dust the pumpkin with boric acid. You don’t need much; a light sprinkling will do.
  4. Using a long-handled grill lighter or long-stick match (not a cigarette-style lighter or typical short match), touch the flame to the surface of the pumpkin to ignite it.

NOTE: If you find that the hand sanitizer doesn’t easily ignite, wait until all flames have died out, then splash a bit of HEET on the outside of the pumpkin and re-ignite it.

The alcohol in the hand sanitizer will create blue flames, boric acid will create green flames, you will see a bit of yellow flame from the reaction of the sodium in the pumpkin flesh, and the light reflecting from the pumpkin’s flesh will appear orange.

Amaze your friends, but do it safely, and share how your #flamingpumpkin worked for you.