At Home With Hands On!

Flaming Benjamins (7/6/16)

**WARNING! Never play with fire! If you want to try to recreate these experiments, be sure to ask for permission and assistance from an adult friend!**

flaming benjamins

Photo credit: Epic Slow Mo

MATERIALS:

  • Safety Goggles
  • Fire resistant Safety Gloves (encouraged)
  • Glass or plastic bowl
  • Metal tongs or Long-handled pliers
  • 70% Isopropyl Alcohol
  • Money, Money, Money! (cotton cloth or sheets of scrap paper work just as well, too!)
  • Long-neck lighter

INSTRUCTIONS:flaming money

  1. Put on your safety goggles!
  2. **Caution: It is not safe to play with fire!! Be sure to ask for permission and assistance from an adult friend before trying this experiment!**
  3. Fill a glass or plastic bowl with 70% Isopropyl Alcohol (available at any pharmacy). Leave enough space in the bowl to fully submerge your cotton fabric, paper, or dollar bill in the alcohol.
  4. After fully dipping the sheet in the alcohol, let it sit for about 5 seconds.
  5. Using your metal tongs or long-handled pliers, lift the sheet from the alcohol. Allow any excess drops of alcohol to drip off of the sheet. If it is really wet, you may want to squeeze out some excess alcohol. The sheet should be damp, but not really wet.
  6. Move the bowl of Isopropyl Alcohol a safe distance away.
  7. Dim the lights.
  8. Using a long-neck lighter, light the sheet on fire by slowly bringing the ignited lighter upward toward the object until the flame catches.
  9. After a few seconds, you can either blow out the flame or gently wave the sheet up and down to extinguish the fire.
  10. Once the fire has been fully put out, you feel the sheet: Is it hot? Is it still damp? Why or why not?
  11. Allow the dollar bill to fully dry before returning it to your purse or wallet.
  12. You can pour any extra Isopropyl Alcohol down the sink drain. Be sure to flush it down with clean water for a few seconds.

HOW DOES IT WORK:

Rubbing alcohol does contain a very flammable ingredient called Isopropyl Alcohol. Isopropyl alcohol will burn quickly with a bright orange flame. However, rubbing alcohol contains another ingredient which doesn’t burn so easily. We call it water!

Water is the key to safely performing this experiment, and it is the key to saving the dollar bill from burning away!

The percentage printed on the bottle of Isopropyl alcohol will tell us how much water is actually in the solution. For this experiment, we used 70% Isopropyl alcohol, which means that for every 10 parts of liquid, there are 7 parts Isopropyl alcohol and 3 parts water.

While the Isopropyl Alcohol burns very quickly, the water actually absorbs the heat of the fire and evaporates away!

This explains why, after the fire has been extinguished, the dollar bill feels dry and cool!

Bonus Experiment! Make a FIRE-NADO!

While you have your adult assistant present, ask them to help you build a Fire Tornado (or fire-nado) generator!

MATERIALS:

  • Safety Goggles
  • Fire resistant Safety Gloves (encouraged)
  • Empty soda can
  • Scissors
  • A round turn-table (we used a rotating spice rack!)
  • Metal Chicken Wire and Twist-ties OR a Round Metal Wire Trash Bin
  • 70% Isopropyl Alcohol
  • Long-neck lighter

INSTRUCTIONS:fire-nado

  1. Put on those safety goggles!
  2. With a pair of scissors, carefully cut the bottom half off of an empty aluminum soda can. Be sure to leave at least 2 inches of the can’s side! This will become your fire-resistant fire-nado holder, so it will need to hold at least ¼ cup of Isopropyl Alcohol.
  3. For the fire-nado cage, you will either need to make a tall cylinder from your chicken wire, or if you have a round trash bin made from metal wire, that’s PERFECT! Use that instead!
  4. To make a chicken wire cage, roll and cut a cylinder of wire mesh that has a base slightly smaller than the surface of your turn-table. Attach the wire mesh ends together using twist-ties at the top, middle, and bottom.
  5. On a clean, clear surface (far away from anything flammable!) place your fire-resistant fire-nado soda can base in the very center of the turn-table.
  6. Fill the can about ½ full with 70% Isopropyl Alcohol.
  7. Carefully light the surface of the alcohol using a long-neck lighter.
  8. Gently spin the turn-table, and observe any changes that occur to the fire. Is there any change?
  9. If you are using a wire cylinder: simply stand it upright around your already burning tire-nado base. If you are using a pre-made wire trash bin: first blow out the burning alcohol, place the filled soda can in the center of the wire trash bin, and place the wire trash bin in the center of the turn-table before relighting it.
  10. With the wire grate in place, gently spin the turn-table again. Do you notice any change to the flame now? It’s a fire-nado!

HOW DOES IT WORK:

The spinning turn-table base isn’t the reason why our fire-nado forms. If it were, the fire-nado would have formed when you spun the turn-table without the wire cage in place! Our fire tornado formed because of the flow of air through the spinning walls of the wire cage.

As the air right in the middle of the wire cage was heated by the flame, it began to rise upward (have you ever heard the saying “heat rises”?). The cooler outside air began to push inward, through the holes in the spinning wire cage, which caused the air to spin! This upward-moving pillar of warm air surrounded by a spiral of cooler air is the secret combination to build a fire vortex (or fire-nado!).