The Goldenrod Paper Secret was passed on to me around 1987 by Dr. Roy Gould of the Harvard CFA, who got it from his brother, an R&D chemist in NYC, who heard about it as the "secret" traveled from chem lab to chem lab across the country. I wrote up this paper and posted it on the web around 1995. Since then it has spread all over the place!
The "good" kind is Astrobrights Galaxy Gold WAAB57A, from Wausau Papers.
Goldenrod paper is available at Edu. Innovations, SM-925
Office supply stores and Kinko's copy centers sell a type of paper called
Astrobrights(tm) Galaxy Gold. It's "goldenrod" in color, sort of a
yellow/orange. Big deal. However, IF ALKALINE SUBSTANCES HIT IT, IT TURNS
MAGENTA! Spray it with Windex, and it instantly turns bright red! Cool!!
Astrobrights Galaxy Gold paper is the worlds largest acid/base indicator
strip. Dip it in a base solution (like ammonia cleaner, baking soda
in water, etc.) and it turns bright red. Dip it in acid (vinegar, lemon
juice, etc.) and it turns yellow again.
(Note: there are other brands of goldenrod which do not work. If in doubt, wet a sample of the paper with ammonia glass cleaner. Kinko's usually has bottles of Windex around)
The fact that an 8.5 x 11 sheet of goldenrod is enormously larger than
your typical acid/base litumus paper test strip makes numerous classroom
demonstrations possible that never could be done before.
Cut it into strips, dip it in acid or base. It turns colors. duh.
Dip it in base so it turns red, then dry it out. This gives you an
acid-indicating paper which starts out red ...and turns yellow in acid.
Put dilute vinegar in one jar, baking-soda solution in another. (Baking
soda dissolves better in warm water.) Use paintbrushes to paint on the
goldenrod. Baking soda solution turns the yellow paper red. The vinegar
solution turns previously-reddened paper yellow. Paint an invisible
picture with vinegar on yellow goldenrod, let it dry, then spray it with
baking soda solution. It turns red everywhere except the places having
Draw "invisible" patterns or messages on the paper with rubber cement,
diluted Elmer's glue, transparent tape, etc., then spray it with alkaline
solution. The paper turns red except where your drawing has sealed it.
Yellow artworks on red background appears.
Wet a strip of previously-reddened goldenrod, then lower the strip into a
half-full glass of carbonated beverage. Don't let the strip touch the
liquid. The strip turns orange as the transparent pool of carbon dioxide
forms carbonic acid in the wet paper. This lets you "see" the invisible
pool of CO2 gas which fills the cup. (Only works in a draft-free room,
where the CO2 gas remains atop the cola.)
Dust your hands with baking soda. Claim that you have "Alien DNA Test
Paper," and if it turns red, it indicates that you are not human. Have
your audience put their thumbprints on some wet Goldenrod paper. Anyone with
baking soda on their fingers (you!) will leave a thumbprint which slowly
ELECTROLYSIS: wet some goldenrod paper with salt water and place it on a
sheet of aluminum foil. Use clipleads to connect the positive terminal of
a 6v or 9v battery to the foil. Connect a wire to the negative battery
terminal. Now drag the negative wire across the wet goldenrod, and it
turns red. Write with electrochemistry! If you reverse the polarity of
the battery, you can erase your red drawings. If you replace the
goldenrod with previously-reddened paper, the reversed battery connections
let you draw in yellow on a red background. (the positive plate creates
acidic solution, while the negative plate makes alkaline.)
MY OLD ACID RAIN DEMO: Wet the inside of a glass jar. Light a match, blow
it out, then collect the smoke inside the upside-down jar. After awhile
the drops of water collect nasty combustion products from the smoke and
become acidic. Touch the drops to previously reddened goldenrod paper,
and it turns yellow, indicating acid. Instant acid rain! And might you
think twice about smoking cigarettes and putting acid in your lungs? I
thought up this one while working at the Museum of Science in Boston.
NOTE: Young kids shouldn't perform the following demonstrations. Ammonia is somewhat toxic, is nasty if inhaled, and is dangerous if splashed in eyes. Adult supervision only. Wear safety goggles.
AMMONIA DEMOS:Wet some goldenrod paper, then drip some ammonia-based cleaner upon it. Notice that the red drops have red haloes around them? Just the ammonia fumes alone can turn the paper red.
Wet some goldenrod paper. Put some ice cubes in a jar, then pour in a
little ammonia and wait for some cold ammonia gas to build up. Carefully
pour the transparent ammonia gas over the wet goldenrod paper, and it
flares red. Dip a wet strip of un-reddened goldenrod into the
seemingly-empty jar, and you'll discover the depth of the pool of cold
ammonia gas. Make wet marks on dry goldenrod, and when cold ammonia gas
is poured over it, the wet marks turn red. (Don't leave the jar of ice
cubes sitting around, dump it out so that passersby can't take a sip from
your glass of "icewater.")
Use a smoke-ring box to shoot invisible ammonia "smoke rings" at wet
goldenrod paper. Little red puffs appear where they hit.
Freak out Kinko's Copies employees by buying one sheet of goldenrod,
asking for the bottle of glass cleaner, then yelling "look!" while
spraying the paper with the ammonia-based cleaner. But be warned, I've
been doing this for awhile, so the secret is spreading from Kinko's to
Kinko's like a mind-virus. They may already know about it.