Rainbow Flames and a Pyrotechnic Pumpkin (10/5/16)
- Heat-resistant container (Pyrex glassware works well)
- Long-necked Lighter
- Metal Baking Tray
- Measuring cup and Measuring spoons
- Liquid fuel, such as: Isopropyl Alcohol, Methanol, or even Antibacterial Hand Sanitizer!
- A variety of Metal Salts to experiment with, for example:
- Sodium Chloride (table salt)
- Sodium Borate (Borax)
- Potassium Chloride (salt substitute)
- Magnesium Sulfate (Epsom salt)
- Calcium Chloride (Ice Melt)
- Hydrogen Borate (Boric acid)
- Safety goggles
- An adult assistant
- Be sure to ask an adult to assist you with this experiment, because it involves open flames and possibly harmful chemicals.
- Place your Metal Baking Tray on a clear and clutter-free surface. This will be your flame-resistant work space.
- Put on your Safety Goggles!
- First, we need to see what color fire is created by burning the liquid fuel on its own.
- Add one Tablespoon of your liquid fuel to a clean, dry Pyrex bowl.
- Hold the lit Long-neck Lighter a few feet away from the Pyrex bowl, and slowly bring the flame toward the liquid fuel. Once the fuel has caught fire, quickly pull the lighter away again.
- Turn down the lights for a better view! From a safe distance, observe the color of the flames that are coming from the burning fuel.
- Allow the fire to burn out, or carefully blow it out without standing very near or over the fire! Pour any remaining liquid fuel into an empty sink, and thoroughly rinse it down the drain for at least 20 seconds. Wash and dry any spoons and bowls.
- Now it’s time to switch up the color! Add two Tablespoons of one Metal Salt to a clean, dry Pyrex bowl. Stir in one Tablespoon of the liquid fuel that you used in the previous experiment. It’s okay if not all of the Metal Salt dissolves.
- Hold the lit Long-neck Lighter a few feet away from the Pyrex bowl, and slowly bring the flame toward the liquid fuel and Metal Salt mixture. Once the fuel has caught fire, quickly pull the lighter away again.
- Turn down the lights for a better view! From a safe distance, observe the color of the flames that are coming from the burning fuel and Metal Salt mixture. Is it burning the same color as before? What do you think is going on?
- Allow the fire to burn out, or carefully blow it out without standing very near or over the fire! Pour any remaining mixture into an empty sink, and thoroughly rinse it down the drain for at least 20 seconds. Wash and dry any spoons and bowls.
- Repeat steps 9 through 12 with different Metal Salts to discover a whole rainbow of fire!
HOW DOES IT WORK:
Most people are familiar with fire that burns with a Red, Orange, or Yellow flame. But fire can also naturally burn Blue or even White. These colors are determined mostly by the heat of the fire itself, with Red being the color of cooler flames and Blue being the hottest! Burning Isopropyl Alcohol (as well as burning Methanol) produces a Blue or even White flame, meaning that it is VERY hot!
So why do the Metal Salts create different colors of fire, like Purple or Green? To explain this, we need to zoom down to the atomic level. Atoms are the basic unit of a chemical element. They are made up of Protons and Neutrons within the central Nucleus, and tiny Electrons that move around the outside. Each type of chemical element has a unique atom, and our Metal Salts are made up of different combinations of these atoms. For example, a single molecule of Sodium Chloride (NaCl) has one Sodium atom linked with one Chlorine atom.
When the Metal Salts are added to the hot fire, their outer-most Electrons absorb some of the energy of the fire and jump away from the center of their own atom. However, the Electrons can’t stay energized for very long, so they quickly jump back toward the center of their atom by releasing this extra energy in the form of Light. Amazingly, each type of atom has very strict rules for how far away their Electrons can possibly jump, or how much energy they can absorb or release. This also means that the light energy that is emitted from one heated Metal Salt is very different from any of others.
Finally, when each light energy enters our eye, it is processed as color by our brain. And because the Metal Salts each produce different light energies, we observe as DIFFERENT COLORS!
THE MORE YOU KNOW:
The practice of using chemical additives to change the color of fire is very common in pyrotechnics, or firework design. That’s actually why fireworks come in so many different colors!
To change the color of their flames, pyrotechnicians usually add Metal Salts. Metal Salts are chemical compounds that form when various acids and bases react with each other. Some familiar Metal Salts are Sodium Chloride (NaCl) or table salt, Magnesium Sulface (MgSO4) or Epsom salt, and Hydrogen Borate (H3BO3) or Boric acid.
Put your new colorful flame knowledge to use this Halloween by lighting up a Pyrotechnic Pumpkin Jack o’ Lantern! Add two Tablespoons of the Metal Salt of your choice into a clean and dry Pyrex glass. Mix in one Tablespoon of liquid fuel.
Working only on a fire-resistant metal pan or baking sheet, carefully lower the filled Pyrex bowl into a pre-carved Jack o’ Lantern.
You can also use a small amount of Antibacterial Hand Sanitizer to coat the outside of your pumpkin for even more flames!
Be sure to have an adult assist you with this experiment! Have a Safe and Happy Halloween!