Join the American Chemical Society at the Illinois State Fair,      Springfield, Illinois

 

Materials:

An opaque pitcher (decorated magically if desired!) 800 mL of distilled water (or tap water if preferred) 5 mL of phenolphthalein solution 5 mL of 1 M HCl solution 5mL of 1 M NaOH solution Four 250-mL beakers or clear plastic cups

Preparation:

Before the demonstration, place the water and phenolphthalein in the pitcher.  It should be such that just 1-2 drops of the NaOH turns the entire solution bright pink.  You may have to adjust it, especially if using tap water, by adding either drops of HCl or NaOH to get the solution to this point.  Essentially this involves titrating it to just pink, then adding 1-2 drops of HCL to bring it back to colorless.  Also, before the demonstration, with no one watching you, dry out the beakers, or cups, then add drops of solution to the bottoms so when viewed from the side they are not noticeable: nothing to beaker A, 5 drops NaOH to beaker B, 10 drops HCL to beaker C, and 10 drops NaOH to beaker D.

Caution:  Eye protection should always be worn when handling chemicals.  Chemicals must be treated with care and respect, and never put in the mouth.   Adult supervision is required.

 

A suggested procedure:

Relate the following anecdote, or one like it, to the audience. Directions are bold and in brackets.

“You may or may not know it, but I used to wait tables back in college. It was a fairly simple job since the restaurant, named ‘Cheesies’ had relatively few menu items to choose from:  cheeseburgers, cheese pizza, and cheese sticks, and to drink:  just water and raspberry Kool-aid.  Even with these limited choices, it seemed I was always in need of a third hand:  one to carry a pitcher of water, one to carry a pitcher of Kool-aid and one to carry the pen and pad to take their orders.  One day, in the chemistry lab, I came up with an ingenious way to solve my problems; I invented my very own magic pitcher [hold it up, proudly], capable of pouring out either water or raspberry Kool-aid on command.  It was very popular with the patrons, and the other waiters were quite envious.  They begged me to let them borrow it, but I told them that if they did not have a strong foundation in chemistry, the pitcher would not work for them.  The pitcher came in especially handy one day when I had an unusually fickle group of four gentlemen sit at one of my tables.  I remember it quite well…

The first asked for water. No problem, I told the pitcher 'water', and out came his water   [pour about 200 mL from the pitcher into beaker A — it should be colorless].

The second asked for Kool-aid. No problem, I told the pitcher 'Kool-aid' and out came his Kool-aid  [pour about 200 mL from the pitcher into beaker B — it should turn dark pink as it his the glass!].

Well, the first guy tried his water, said it tasted funny, so could he please change his to Kool-aid too. No problem, I took back his water [pour beaker A back into the pitcher], and took back the second guy’s Kool-aid [pour beaker B back onto the pitcher], and then I poured them both out the Kool-aid they wanted [pour out pink Kool-aid into beakers A and B]. Well, you all know what the third guy wanted:  that’s right, water.  So I told the pitcher 'water', and out came his water [pour out 200 mL from the pitcher into the beaker C — it should turn colorless.  Most impressive!].

Well, wouldn’t you know it: now the first two guys said they thought that water looked mighty fine, and asked if I wouldn’t mind changing theirs back to water. By then I was getting a little frustrated, but I was trying not to show it, so I took back their two Kool-aids [pour beaker A and B back into the pitcher], and of course I had to take back the third guy’s water [pour beaker C back into the pitcher], then I poured all three out the water they wanted [pour out colorless water into beakers A, B, and C].  And what do you suppose the fourth guy wanted?  You got it: Kool-aid. So I told the pitcher 'Kool-aid', and out it came [pour about 200mL from the pitcher into the beaker D — it should turn dark pink!].

Well, the first guy started to say something, but I just cut him off and said I know, I know, you all want Kool-aid, so I grabbed up their waters, as well as the fourth guy’s Kool-aid [with frustration on your face, pour all four beakers back into the pitcher…].  I said, ‘There you go, are you happy!?’  And the first guy said ‘Actually, we were hoping for milk.’   ‘I quit.’

Warning:  This is NOT Kool-aid.  It is a series of chemicals that take on the appearance of Kool-aid.  They should NEVER BE DRUNK, and can be harmful if they come in contact with the skin, eyes, or mouth.  Treat these chemicals with respect, and they must be handled with adult supervision!

----Contributed by Jackie Stewart, Mark Twain Section