Nonburning Money: Difference between revisions

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== Age ==
{| class="wikitable" style="color:black; background-color:#ddd; margin-left: auto; float:right"
| [[Chemistry]]:
| Heat Capacity, Alcohol Flammability
|-
| Grade Range:
| [[Elementary School]], [[Middle School]], [[High School]]
|-
| Format:
| [[Stage]]
|}


Elementary School, Middle School, High School
As with all fire demonstrations, keep a fire extinguisher nearby as a precaution. This demonstration is a favorite among both presenters and students, and is often requested and performed at all grade levels.
 
== Format ==
 
Stage Show, Hands-on


== Materials ==
== Materials ==


    50/50 (v/v) solution of isopropyl alcohol and distilled water
* Nonburning Solution
    2 100 mL beakers
** Ethanol or Isopropyl Alcohol
    A dollar
** Water
    Firestarter
** Table Salt
    Tongs
* Dollar Bill & Cloth
    Tweezers
* 2 Small Tubs
* 2 Large Tubs
* Lighter
* Tongs


== Safety Precautions ==
== Safety Precautions ==


Science Theatre demonstrators must keep the safety of themselves and their audience in mind at all times. All Science Theatre demonstrators must have read through the Safety Training page. The ST Safety Box with first aid kit, fire extinguisher, etc. should always be available to demonstrators. Always wear safety gloves, glasses, and a labcoat if handling chemicals; always perform potentially dangerous demonstrations at a safe distance from the audience; and always keep a very close eye on any volunteers you call from the audience. To avoid burns the flaming dollar/towel must be handled with care at all times. Combustible materials should NOT be in the vicinity, and a fire extinguisher should be readily available. Isopropyl alcohol can damage the eyes severely, so safety goggles should be worn when preparing for and performing this demonstration. Gloves are also a must. Safety never takes a vacation.
Please read the Fire Safety section of the [[Demonstration Safety]] page before performing this demonstration.


[http://www.sciencelab.com/msds.php?msdsId=9926005: Isopropyl Alcohol MSDS]
This demonstration requires: Safety glasses, small blast shield, fireproof gloves
 
== Preparation ==
 
Ensure that there is enough of the nonburning solution for the show you are performing. If possible, dim the lights before performing this demonstration.


== Demonstration ==
== Demonstration ==


1. Pick up the dollar with tweezers and place it in about 40 mL of nonburning solution. Allow the dollar to soak up the isopropyl and water for at least one minute.
;Preparation:
 
* Prepare the nonburning solution: In a 1 quart bottle, combine the alcohol and the water in equal amounts, making a 50/50 solution. To make the flame more visible, you may want to mix in 2-3 tablespoons of salt, which will make it a bright orange-yellow flame rather than a faint blue flame.
2. Pick up the dollar with tongs and hold it over a spot in your presentation area away from the alcohol solution.
 
3. Light the dollar from the bottom and allow the flame to travel up the bill.
 
== What to Say ==
 
What normally happens when you light paper on fire? This is just your normal, run of the mill dollar bill. (You may pass the bill around here. Then begin to soak it in the nonburning solution.) This solution is made up of 50% water and 50% isopropyl alcohol. As it is sitting in the beaker, the dollar is soaking up both the water and alcohol. When a minute has elapsed and the dollar has soaked long enough, pull it out of the solution and move the solution away from the area where you intend to ignite the bill. Ask, what do you think will happen if I try to light this dollar on fire? Let’s find out.
 
Okay, so the dollar is on fire, but it is not burning. How is this possible? This is possible because the alcohol the dollar was soaked in is a highly flammable substance. It has a low vapor pressure as compared to the water in the solution. So the alcohol lights aflame while the water which has absorbed into the dollar never gets hot enough to fully evaporate. So the dollar does not burn. When the alcohol has all burned away the flame extinguishes.


When you are sure that the dollar is cool enough to handle, you can pass the dollar around to the students again to show them that the actual dollar was not burned at all (hopefully).
;Presentation:
# Set out the tubs (small tubs if using a dollar bill, large tubs if using the cloth) and fill one halfway with water. Fill the other tub with the nonburning solution, enough to cover the bottom of the tub with a thin layer. Close the bottle with the nonburning solution and move it off the table, setting it at least five feet away from the demonstration area. Put the dollar bill or cloth into the solution, and have it soak thoroughly.
# Explain to the audience that you will be making a fire. Have the students list the three things needed for a fire (oxygen, a fuel source, an ignition source).
# Explain that you will be using an alcohol, and that alcohols are flammable. Ask the students for ideas on what will happen when you ignite the dollar bill/cloth that is soaked in alcohol. During this time, put on the safety gear and use the tongs to pick up the dollar bill/cloth and hold it over the tub of water.
# Have students do a countdown, and ignite the dollar bill/cloth. It will burn for several seconds, but then the flame will go out, leaving it intact! dunk it briefly in the water afterwards to cool it down before handling it, and ask the students for ideas on why it didn't burn. Is there something else in the solution?


== Why It Is ==
== Why This Works ==


Alcohol is a volatile, highly flammable chemical. Therefore, when we tried to light the dollar on fire, the alcohol lit on fire, but the water that was absorbed into the dollar protected it from burning. If the alcohol stayed on fire longer there is the possibility that all of the water would evaporate and then the bill itself would light on fire.
===Short Explanation===
Alcohols are extremely flammable, and burn very hot and very quickly. This is because alcohols are ''Volatile'', which means they easily turn into a vapor and mix into the air. This means that we have to be careful about having alcohol near a fire or anything really hot, because if not carefully watched it might ignite! With the Dollar bill/cloth, we had it soaked in a solution that was half alcohol and half water. The water did not stop the alcohol from burning, and it was able to ignite and start burning quickly. However, water has a high ''Heat Capacity'', meaning it can absorb a lot of heat before turning into steam. This means the water was able to absorb all the heat from the alcohol, and kept the dollar bill/cloth safe from the fire!


This is a good demonstration for older kids and high school students because you can discuss chemical reactions. The reaction performed here was a combustion reaction because the reactants included an organic molecule (isopropyl alcohol) and oxygen, which yielded carbon dioxide and water. Note the highly negative reaction energy, indicating that this reaction is highly exothermic.
===Full Explanation===
Alcohols are organic compounds which readily combust when exposed to a heat source. Alcohols are highly ''Volatile'', meaning that they readily vaporize while at standard pressure and temperature. Alcohols also have a low ''Heat Capacity'', meaning that they can only absorb a small amount of heat before vaporizing or igniting. Alcohols such as ethanol readily decompose and release a large amount of energy when ignited:


2 C3H7OH (l) + 9 O2 → 6 CO2 (g) + 8 H2O (g) -1987 kJ/mole
{| class="wikitable" style="color:black; background-color:#ddd; text-align: left; margin-right: auto"
| Ethanol + 3 O<sub>2 (g)</sub>
(C<sub>2</sub>H<sub>5</sub>OH)
| '''→'''
| 2 CO<sub>2</sub> + 3 H<sub>2</sub>O + Heat
(1 mol ethanol = 12.3 MJ)
|}


For younger students, it may be enough to say that the alcohol in the solution burns easily. This substance will burn off quickly and the dollar will not burn at all.
One mole of ethanol is only 2.5 cups (0.58 l), and 12.3 MJ is equivalent to the kinetic energy of a flatbed tow truck moving 100 mph (160 km/h)! This fact, as well as the relative ease in igniting ethanol, is why it is now used as a fuel source. Water, unlike alcohols, is not very volatile and has a high heat capacity. The old proverb "A watched pot never boils" draws from the fact that water takes a while to get up to temperature. In fact, to get 2.5 cups of water from room temperature to heat up and vaporize, you would need about 15 MJ of heat energy, which is nearly 25% more than what an equal amount of ethanol can provide! This is what results in the dollar bill or cloth being unscathed and intact!


== Real Life Examples ==
This demonstration also shows us a technique used in movies. When a stunt requires someone to be "burned alive", the stunt performer will wear a suit which either is padded with water-filled pockets or is heavily soaked in water. That way, when they are covered in the combustible material and ignited, the water will absorb the heat and keep them safe!


You can tell the audience about other alcohols, such as methanol, and ethanol. Methanol is known as wood alcohol, is present in antifreeze, solvent and fuel. Methanol is poisonous because when in the body it is broken by alcohol dehydrogenase into formic acid and formaldehyde. Formaldehyde is the chemical used to preserve bodies after death. If ingested it leads to damage of the optic nerve. Ethanol or grain alcohol is the common type of alcohol present in wine, beer and other spirits. Ethanol is now being tested as a fuel for vehicles. It has long been used as antiseptic and even as an antidote to methanol poisoning.
== Additional Information ==


Mention that we have another demonstration in which we show the extreme flammability of volatile alcohols. In methanol cannons we put methanol into a water cooler and allow the methanol to vaporize. When the vapor is introduced to fire, the methanol lights on fire and flames erupt out of the bottle.
* This demonstration pairs well with the [[Methanol Cannon]], and these two can then be used to compare the types of alcohols. Methanol is known as wood alcohol and is used in antifreeze, solvent and some fuels. Methanol is poisonous, and when ingested is broken down into formic acid and formaldehyde, or embalming fluid. Ethanol is the type of alcohol present in wine, beer and other spirits. Ethanol is also used as a fuel in vehicles, and has long been used as antiseptic.
* This demonstration is a part of the [[Fire and Ice Show]]

Latest revision as of 18:43, 22 August 2016

Chemistry: Heat Capacity, Alcohol Flammability
Grade Range: Elementary School, Middle School, High School
Format: Stage

As with all fire demonstrations, keep a fire extinguisher nearby as a precaution. This demonstration is a favorite among both presenters and students, and is often requested and performed at all grade levels.

Materials

  • Nonburning Solution
    • Ethanol or Isopropyl Alcohol
    • Water
    • Table Salt
  • Dollar Bill & Cloth
  • 2 Small Tubs
  • 2 Large Tubs
  • Lighter
  • Tongs

Safety Precautions

Please read the Fire Safety section of the Demonstration Safety page before performing this demonstration.

This demonstration requires: Safety glasses, small blast shield, fireproof gloves

Demonstration

Preparation
  • Prepare the nonburning solution: In a 1 quart bottle, combine the alcohol and the water in equal amounts, making a 50/50 solution. To make the flame more visible, you may want to mix in 2-3 tablespoons of salt, which will make it a bright orange-yellow flame rather than a faint blue flame.
Presentation
  1. Set out the tubs (small tubs if using a dollar bill, large tubs if using the cloth) and fill one halfway with water. Fill the other tub with the nonburning solution, enough to cover the bottom of the tub with a thin layer. Close the bottle with the nonburning solution and move it off the table, setting it at least five feet away from the demonstration area. Put the dollar bill or cloth into the solution, and have it soak thoroughly.
  2. Explain to the audience that you will be making a fire. Have the students list the three things needed for a fire (oxygen, a fuel source, an ignition source).
  3. Explain that you will be using an alcohol, and that alcohols are flammable. Ask the students for ideas on what will happen when you ignite the dollar bill/cloth that is soaked in alcohol. During this time, put on the safety gear and use the tongs to pick up the dollar bill/cloth and hold it over the tub of water.
  4. Have students do a countdown, and ignite the dollar bill/cloth. It will burn for several seconds, but then the flame will go out, leaving it intact! dunk it briefly in the water afterwards to cool it down before handling it, and ask the students for ideas on why it didn't burn. Is there something else in the solution?

Why This Works

Short Explanation

Alcohols are extremely flammable, and burn very hot and very quickly. This is because alcohols are Volatile, which means they easily turn into a vapor and mix into the air. This means that we have to be careful about having alcohol near a fire or anything really hot, because if not carefully watched it might ignite! With the Dollar bill/cloth, we had it soaked in a solution that was half alcohol and half water. The water did not stop the alcohol from burning, and it was able to ignite and start burning quickly. However, water has a high Heat Capacity, meaning it can absorb a lot of heat before turning into steam. This means the water was able to absorb all the heat from the alcohol, and kept the dollar bill/cloth safe from the fire!

Full Explanation

Alcohols are organic compounds which readily combust when exposed to a heat source. Alcohols are highly Volatile, meaning that they readily vaporize while at standard pressure and temperature. Alcohols also have a low Heat Capacity, meaning that they can only absorb a small amount of heat before vaporizing or igniting. Alcohols such as ethanol readily decompose and release a large amount of energy when ignited:

Ethanol + 3 O2 (g)

(C2H5OH)

→ 2 CO2 + 3 H2O + Heat

(1 mol ethanol = 12.3 MJ)

One mole of ethanol is only 2.5 cups (0.58 l), and 12.3 MJ is equivalent to the kinetic energy of a flatbed tow truck moving 100 mph (160 km/h)! This fact, as well as the relative ease in igniting ethanol, is why it is now used as a fuel source. Water, unlike alcohols, is not very volatile and has a high heat capacity. The old proverb "A watched pot never boils" draws from the fact that water takes a while to get up to temperature. In fact, to get 2.5 cups of water from room temperature to heat up and vaporize, you would need about 15 MJ of heat energy, which is nearly 25% more than what an equal amount of ethanol can provide! This is what results in the dollar bill or cloth being unscathed and intact!

This demonstration also shows us a technique used in movies. When a stunt requires someone to be "burned alive", the stunt performer will wear a suit which either is padded with water-filled pockets or is heavily soaked in water. That way, when they are covered in the combustible material and ignited, the water will absorb the heat and keep them safe!

Additional Information

  • This demonstration pairs well with the Methanol Cannon, and these two can then be used to compare the types of alcohols. Methanol is known as wood alcohol and is used in antifreeze, solvent and some fuels. Methanol is poisonous, and when ingested is broken down into formic acid and formaldehyde, or embalming fluid. Ethanol is the type of alcohol present in wine, beer and other spirits. Ethanol is also used as a fuel in vehicles, and has long been used as antiseptic.
  • This demonstration is a part of the Fire and Ice Show
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