Rainbow Connection: Difference between revisions

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


Elementary School, Middle School, High School
Coordinated to ''The Rainbow Connection'' by Kermit the Frog, this demonstration is a sight to behold for all ages. Students and teachers alike will enjoy watching the solutions go from colorless to colorful and back again! This demonstration does require a lot of preparation prior to the event, and should be practiced beforehand as well.
 
== Format ==
 
Stage Show


== Materials ==
== Materials ==


    2.85 g phenolphthalein.
* Six Indicator Solutions (See '''Preparation''')
    21.0 g m-nitrophenol
* Sodium Hydroxide
    2.5 g thymolphthalein
* Sulfuric Acid
    590 mL 95% ethanol
* Water
    250 mL of 0.05 M sulfuric acid
* Ethanol
    1200 mL of 0.015 M NaOH
* Glycerol
    10 mL of 18 M H2SO4
* Six 1000mL Beakers
    20 mL of glycerol
* 4000mL Beaker
    100 mL of 0.2 M NaOH
* 2L Pitcher
    7 30 mL dropping bottles
* Two 500mL Bottles
    20 oz clear soda bottle
* Seven 50mL Bottle
    A clear Pitcher
* Large Stir Rod
    6 glass tumblers (12 oz)
* Eyedropper
    A glass stir rod
* Small Cloth
    White backdrop
* Fluorescent Light Box
    Towel
* "Rainbow Connection" song w/speaker system
    Copy of the Rainbow Connection song by Kermit.
    Something to play the song with (e.g. speaker setup)


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


Keep the audience at safe distance there is a splash hazard with these acids and bases. You MUST were splash proof goggles and a lab coat. Avoid contact of acids with the skin; it can cause burns. The solutions are at low concentrations but still take care when handling them. Care must be taken when mixing the HSO-glycerol solution since the solution will become hot. Allow it to cool overnight. 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.
Please read the Liquid Chemical section of the [[Demonstration Safety]] page before performing this demonstration. All solutions in this demonstration are of low concentrations, and the final solution can be safely poured down a drain.
 
    Phenolphthalein MSDS
    m-Nitrophenol MSDS
    Thymolphthalein MSDS
    95% Ethyl Alcohol (190 proof) MSDS
    .05M Sulfuric Acid MSDS (<.1M)
    .0015M Sodium Hydroxide MSDS (<.02M)
    18M Sulfuric Acid MSDS
    Glycerin MSDS
    .2M Sodium Hydroxide
 
== Preparation ==
 
The indicators must first be dissolved in the following proportions with 30 mL of ethanol.
 
RED
    1.5 g phenolphthalein with 3.0 g m-nitrophenol
ORANGE
    0.45g phenolphthalein with 6.0 g m-nitrophenol
YELLOW
    6.0 g m-nitrophenol
GREEN
    0.6 g thymolphthalein with 6.0 m-nitrophenol
BLUE
    1.5 g thymolphthalein
VIOLET
    0.9 g phenolphthalein with 0.4 g thymolphthalein


    Store the solution in a dropping bottle label with the correct color.
This demonstration requires: Safety glasses
    Mix 250 mL of 0.05 M sulfuric acid with 250 mL of Ethanol and store in the soda bottle.
    Transfer to 1200 mL of 0.012 NaOH into the pitcher.
    Put 100 mL of 0.2 M NaOH solution into a dropper bottle.
    Dissolve the HSO in the glycerol and store in a dropper bottle. WILL BECOME HOT
    Clean the glass tumblers and arrange them in a row. Place 2 drops of the red indicator into the first tumbler and proceed with the orange indicator in the next tumbler. Repeat for each indicator in an individual tumbler. Place them in the correct order red – violet.
    Allow the indicator solutions to dry in the tumblers (2 hours)
    Place the tumblers in succession on the white backdrop, red – violet.


== Demonstration ==
== Demonstration ==


Begin to play the song.
;Preparation:
Pick up every tumbler in succession pretending to clean in with the towel. Place them back into the correct place. Do not break the film on the bottom.
* Prepare the .015M Sodium Hydroxide (NaOH) solutions: Mix 1.2g of NaOH with 2000mL of DI water. Store in a 2L plastic pitcher, and label and date it.
 
* Prepare the .2M NaOH solution: Mix 1.2g of NaOH with 200mL of DI water. Store in a 500mL plastic bottle, and label and date it.
Add equal volumes (1.5 oz) of the acid- alcohol solution into each tumbler. Try not to pour directly onto the film so it does not break up and react to quick in the next step.
* Prepare the .05M Sulfuric Acid (H<sub>2</sub>SO<sub>4</sub>) solution: Mix 1.025mL of H<sub>2</sub>SO<sub>4</sub> with 250mL of water. Once mixed, add 250mL of ethanol. Store in a 500mL bottle, and label and date it.
 
* Prepare the Acid Glycerol: Measure 20mL of glycerol in a small beaker, and measure 10mL of H<sub>2</sub>SO<sub>4</sub> with a small graduated cylinder. slowly mix the H<sub>2</sub>SO<sub>4</sub> into the glycerol, which will turn yellow and heat up as it is added. Once all the acid is in, store the solution in a 50mL bottle, and label and date it.
Add the 0.012 M NaOH solution from the pitcher to each tumbler. Fill them halfway and make sure to add the solution on the side of the tumbler so the colors do not flash the color.
* Prepare the indicators: Mix each of the following indicator ratios with 30mL of ethanol. Store the indicator solutions in 50mL bottles, and label and date them.
 
**<span style="color: red">'''Red'''</span>: 1.5 g Phenolphthalein with 3.0 g m-Nitrophenol
The demonstrator should look at the tumblers (should to clear still) and the pitcher to observe that more solution can be added to the tumblers. Then fill the tumblers to ¾th’s full with the remaining NaOH solution in the pitcher pouring rapidly so the colors instantly become colored.
**<span style="color: orange">'''Orange'''</span>: 0.45g Phenolphthalein with 6.0 g m-Nitrophenol
 
**<span style="color: yellow">'''Yellow'''</span>: 6.0 g m-Nitrophenol
Take the dropping bottle of HSO-glycerol and add 3-4 drops to each tumbler (titrate to determine actual amount). This solution should drop to the bottom since it is denser than the basic solution.
**<span style="color: green">'''Green'''</span>: 0.6 g Thymolphthalein with 6.0 m-Nitrophenol
 
**<span style="color: blue">'''Blue'''</span>: 1.5 g Thymolphthalein
Stir the tumblers rapidly to break up to the HSO-glycerol droplets which with make the solution acidic once more and return the tumblers to the original clear state. (DO NOT want to long to move to the next step or the solution will be permanently clear.)
**<span style="color: violet">'''Violet'''</span>: 0.9 g Phenolphthalein with 0.4 g Thymolphthalein
 
Using the dropper bottle of 0.2 M NaOH and a stirring rod, rapidly titrate the solution back to the original color.


The tumblers are then poured into the pitch. The resulting solution is colorless
;Presentation:
# 1-2 hours prior to the event, use an eyedropper to put 3-5 drops of each indicator into their respective beakers. Have the drops land in the center of the beaker, and allow them to dry.
# Set up the demonstration: put the light box on a table and plug it in, keeping the lights off. Set the beakers on the light box in color order, having the sides with the letter labels facing the box. plug in/hook up the stereo system, making sure you have ''The Rainbow Connection'' ready to play. Put 5-10mL of the acid glycerol in the bottom of the 4000mL beaker and set it next to the light box. Set the solutions on the table, either alongside the light box or behind it, as well as the eyedropper, stir rod, cloth.
# When ready to present this demonstration, Get the audience's attention and announce that you will be showing them a short presentation accompanied by a song. Ask the audience to stay quiet throughout the song, stating that you will be answering questions at the end.
# Start ''The Rainbow Connection'', and proceed with the demonstration. Once you finish the demonstration, ask the audience for any questions before proceeding with the explanation.
#*''NOTE: This demonstration is coordinated to the song. In order to perform this demonstration, you will need to have learned the timing and rhythm of the song so you don't miss any of the steps. It is required that you practice this demonstration prior to presenting it because of this.
{| class="wikitable" style="color:black; text-align: left; margin: auto"
|Time || Part of Song || Action
|-
|0:00 - 0:08 || Intro || None
|-
|0:08 - 0:16 || Intro || Turn on lights in light box
|-
|0:16 - 0:40 || 1st & 2nd Lines of Lyrics || Pick up beakers in succession, and mime wiping them clean with the cloth. While doing so, don't break the films in the bottoms of the beakers.
|-
|0:40 - 0:52 || 3rd Line of Lyrics || Pour 100mL of the .05M H<sub>2</sub>SO<sub>4</sub> solution into each of the beakers.
|-
|0:52 - 1:04 || Refrain || Pour 100mL of the .015M NaOH solution into each of the beakers. Each one will have a slight flash of color, but they all will stay clear.
|-
|1:04 - 1:10 || Transition || Look at the beakers confused, pondering why they didn't change color.
|-
|1:10 - 1:34 || 4th & 5th Line of Lyrics || Pour another 200-300mL of the .015M NaOH solution into each of the beakers. They will all become colored!
|-
|1:34 - 1:58 || 6th Line of Lyrics & Refrain || Put a few drops of the acid glycerol into each beaker, stirring as you add them, until they lose their color.
|-
|1:58 - 2:10 || Bridge || Look at the beakers, then at the audience. Give the audience a sad face, then snap your fingers and act excited.
|-
|2:10 - 2:22 || 7th Line of Lyrics || Shuffle around with the bottles and solutions, acting like you are trying to find a particular bottle. Excitedly show the bottle with the .2M NaOH solution to the audience, and look between them and the beakers with a big grin.
|-
|2:22 - 2:46 || 8th & 9th Line of Lyrics || Pour 30-40mL of the .2M NaOH solution into each beaker while stirring to bring the color back. After finding the color for each beaker, stand back and mime "Ta-da!" to the audience.
|-
|2:46 - 2:58 || Refrain || Sing along with the refrain. Try to get the audience to sing with you!
|-
|2:58 - 3:14 || Conclusion || Pour all the solutions in the beakers into the large beaker. The colors for each of them will vanish as you do so.
|}


== What to Say ==
== Why This Works ==


Nothing is said during the demonstration. Afterward, the presence of acid/ base indicators can be discussed. Each indicator used turns a different color in the same pH range and the mixture of indicators allows different wavelengths of light to be absorbed. With these different wavelengths absorbed by the solution we see a new color.
The Rainbow Connection is a dramatic demonstration about acids and bases. ''Acids'' are solutions that have a free positive ion, such as the hydrogen ion (H<sup>+</sup>), while ''Bases'' are solutions that have a free negative ion, such as the hydroxide ion (OH<sup>-</sup>). A notable fact about acids and bases are that they neutralize each other; if you add equal concentrations of an acid to a base, then the solution will be neutral. Acids and bases have a wide variety of uses, and are both used extensively in all kinds of products and materials.


== Why It Is ==
{| class="wikitable" style="color:black; background-color:#ddd; text-align: left; margin-right: auto"
| '''Acid/Base'''
| '''Examples'''
| '''Common Uses'''
|-
| Strong Acids
| Hydrochloric Acid (HCl)
Sulfuric Acid (H<sub>2</sub>SO<sub>4</sub>)
| Toilet Bowl Cleaner (Dilute HCl)
Car Batteries (H<sub>2</sub>SO<sub>4</sub>)
|-
| Strong Bases
| Sodium Hydroxide (NaOH)
Calcium Hydroxide (Ca(OH)<sub>2</sub>)
| Manufacturing of Soap, Paper and Rayon (NaOH)
Bleaching Powder (Ca(OH)<sub>2</sub>)
|-
| Weak Acids
| Acetic Acid (CH<sub>3</sub>COOH)
Citric Acid (C<sub>6</sub>H<sub>8</sub>O<sub>7</sub>)
| Cooking & Cleaning (Vinegar = dilute CH<sub>3</sub>COOH)
Vitamins and Fruits (Vitamin C = C<sub>6</sub>H<sub>8</sub>O<sub>7</sub>)
|-
| Weak Bases
| Baking Soda (NaHCO<sub>3</sub>)
Calcium Carbonate (CaCO<sub>3</sub>)
| Baking and Fire Suppressant (NaHCO<sub>3</sub>)
Antacids and Chalk (CaCO<sub>3</sub>)
|}


“An acid-base indicator is a weak acid or a weak base. The undissociated form of the indicator is a different color than the iogenic form of the indicator. An Indicator does not change color from pure acid to pure alkaline at specific hydrogen ion concentration, but rather, color change occurs over a range of hydrogen ion concentrations. This range is termed the color change interval. It is expressed as a pH range.”[2] As before, each indicator has a different color for the same pH range. Then the mixture of the indicators allow for new colors to be observed.
Normally, you cannot tell from looking at a solution if it is acidic or basic. This is why we are using ''Acid-Base Indicators'' in our solutions. Acid-base indicators are compounds that, when exposed to an acidic or basic solutions, undergo a color shift. In this demonstration, all of the indicators we use are sensitive to basic solutions, and will become colored when they are exposed to a base. By using a mix of different types of indicators, as well as by making the solution basic, we can get a rainbow of colors to form!


== Real Life Examples ==
== Additional Information ==


Mixing water color paints gives the same effect as mixing the indicators.
* ''The Rainbow Connection'' by Kermit the Frog was first sung in 1979, and made it on the list of the 25 most popular songs for that year.
* This demonstration pairs well with the [[Shaking Solution]] and the [[Bouncing Raisins]] demonstrations.

Latest revision as of 14:43, 29 September 2016

Chemistry: Acids and Bases, Indicators
Grade Range: Elementary School, Middle School, High School
Format: Stage

Coordinated to The Rainbow Connection by Kermit the Frog, this demonstration is a sight to behold for all ages. Students and teachers alike will enjoy watching the solutions go from colorless to colorful and back again! This demonstration does require a lot of preparation prior to the event, and should be practiced beforehand as well.

Materials

  • Six Indicator Solutions (See Preparation)
  • Sodium Hydroxide
  • Sulfuric Acid
  • Water
  • Ethanol
  • Glycerol
  • Six 1000mL Beakers
  • 4000mL Beaker
  • 2L Pitcher
  • Two 500mL Bottles
  • Seven 50mL Bottle
  • Large Stir Rod
  • Eyedropper
  • Small Cloth
  • Fluorescent Light Box
  • "Rainbow Connection" song w/speaker system

Safety Precautions

Please read the Liquid Chemical section of the Demonstration Safety page before performing this demonstration. All solutions in this demonstration are of low concentrations, and the final solution can be safely poured down a drain.

This demonstration requires: Safety glasses

Demonstration

Preparation
  • Prepare the .015M Sodium Hydroxide (NaOH) solutions: Mix 1.2g of NaOH with 2000mL of DI water. Store in a 2L plastic pitcher, and label and date it.
  • Prepare the .2M NaOH solution: Mix 1.2g of NaOH with 200mL of DI water. Store in a 500mL plastic bottle, and label and date it.
  • Prepare the .05M Sulfuric Acid (H2SO4) solution: Mix 1.025mL of H2SO4 with 250mL of water. Once mixed, add 250mL of ethanol. Store in a 500mL bottle, and label and date it.
  • Prepare the Acid Glycerol: Measure 20mL of glycerol in a small beaker, and measure 10mL of H2SO4 with a small graduated cylinder. slowly mix the H2SO4 into the glycerol, which will turn yellow and heat up as it is added. Once all the acid is in, store the solution in a 50mL bottle, and label and date it.
  • Prepare the indicators: Mix each of the following indicator ratios with 30mL of ethanol. Store the indicator solutions in 50mL bottles, and label and date them.
    • Red: 1.5 g Phenolphthalein with 3.0 g m-Nitrophenol
    • Orange: 0.45g Phenolphthalein with 6.0 g m-Nitrophenol
    • Yellow: 6.0 g m-Nitrophenol
    • Green: 0.6 g Thymolphthalein with 6.0 m-Nitrophenol
    • Blue: 1.5 g Thymolphthalein
    • Violet: 0.9 g Phenolphthalein with 0.4 g Thymolphthalein
Presentation
  1. 1-2 hours prior to the event, use an eyedropper to put 3-5 drops of each indicator into their respective beakers. Have the drops land in the center of the beaker, and allow them to dry.
  2. Set up the demonstration: put the light box on a table and plug it in, keeping the lights off. Set the beakers on the light box in color order, having the sides with the letter labels facing the box. plug in/hook up the stereo system, making sure you have The Rainbow Connection ready to play. Put 5-10mL of the acid glycerol in the bottom of the 4000mL beaker and set it next to the light box. Set the solutions on the table, either alongside the light box or behind it, as well as the eyedropper, stir rod, cloth.
  3. When ready to present this demonstration, Get the audience's attention and announce that you will be showing them a short presentation accompanied by a song. Ask the audience to stay quiet throughout the song, stating that you will be answering questions at the end.
  4. Start The Rainbow Connection, and proceed with the demonstration. Once you finish the demonstration, ask the audience for any questions before proceeding with the explanation.
    • NOTE: This demonstration is coordinated to the song. In order to perform this demonstration, you will need to have learned the timing and rhythm of the song so you don't miss any of the steps. It is required that you practice this demonstration prior to presenting it because of this.
Time Part of Song Action
0:00 - 0:08 Intro None
0:08 - 0:16 Intro Turn on lights in light box
0:16 - 0:40 1st & 2nd Lines of Lyrics Pick up beakers in succession, and mime wiping them clean with the cloth. While doing so, don't break the films in the bottoms of the beakers.
0:40 - 0:52 3rd Line of Lyrics Pour 100mL of the .05M H2SO4 solution into each of the beakers.
0:52 - 1:04 Refrain Pour 100mL of the .015M NaOH solution into each of the beakers. Each one will have a slight flash of color, but they all will stay clear.
1:04 - 1:10 Transition Look at the beakers confused, pondering why they didn't change color.
1:10 - 1:34 4th & 5th Line of Lyrics Pour another 200-300mL of the .015M NaOH solution into each of the beakers. They will all become colored!
1:34 - 1:58 6th Line of Lyrics & Refrain Put a few drops of the acid glycerol into each beaker, stirring as you add them, until they lose their color.
1:58 - 2:10 Bridge Look at the beakers, then at the audience. Give the audience a sad face, then snap your fingers and act excited.
2:10 - 2:22 7th Line of Lyrics Shuffle around with the bottles and solutions, acting like you are trying to find a particular bottle. Excitedly show the bottle with the .2M NaOH solution to the audience, and look between them and the beakers with a big grin.
2:22 - 2:46 8th & 9th Line of Lyrics Pour 30-40mL of the .2M NaOH solution into each beaker while stirring to bring the color back. After finding the color for each beaker, stand back and mime "Ta-da!" to the audience.
2:46 - 2:58 Refrain Sing along with the refrain. Try to get the audience to sing with you!
2:58 - 3:14 Conclusion Pour all the solutions in the beakers into the large beaker. The colors for each of them will vanish as you do so.

Why This Works

The Rainbow Connection is a dramatic demonstration about acids and bases. Acids are solutions that have a free positive ion, such as the hydrogen ion (H+), while Bases are solutions that have a free negative ion, such as the hydroxide ion (OH-). A notable fact about acids and bases are that they neutralize each other; if you add equal concentrations of an acid to a base, then the solution will be neutral. Acids and bases have a wide variety of uses, and are both used extensively in all kinds of products and materials.

Acid/Base Examples Common Uses
Strong Acids Hydrochloric Acid (HCl)

Sulfuric Acid (H2SO4)

Toilet Bowl Cleaner (Dilute HCl)

Car Batteries (H2SO4)

Strong Bases Sodium Hydroxide (NaOH)

Calcium Hydroxide (Ca(OH)2)

Manufacturing of Soap, Paper and Rayon (NaOH)

Bleaching Powder (Ca(OH)2)

Weak Acids Acetic Acid (CH3COOH)

Citric Acid (C6H8O7)

Cooking & Cleaning (Vinegar = dilute CH3COOH)

Vitamins and Fruits (Vitamin C = C6H8O7)

Weak Bases Baking Soda (NaHCO3)

Calcium Carbonate (CaCO3)

Baking and Fire Suppressant (NaHCO3)

Antacids and Chalk (CaCO3)

Normally, you cannot tell from looking at a solution if it is acidic or basic. This is why we are using Acid-Base Indicators in our solutions. Acid-base indicators are compounds that, when exposed to an acidic or basic solutions, undergo a color shift. In this demonstration, all of the indicators we use are sensitive to basic solutions, and will become colored when they are exposed to a base. By using a mix of different types of indicators, as well as by making the solution basic, we can get a rainbow of colors to form!

Additional Information

  • The Rainbow Connection by Kermit the Frog was first sung in 1979, and made it on the list of the 25 most popular songs for that year.
  • This demonstration pairs well with the Shaking Solution and the Bouncing Raisins demonstrations.
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