Presented by John Dantoni, Wayne Valley H.S., Wayne, N.J.

Application
Acid/base indicators motivation observation studies

Theory
Goldenrod paper will change color from gold to red when contacted with a base such as the ammonia solution.

Materials
Large beaker
Ammonia solution, household type purchased in supermarket
Goldenrod paper (science supply house such as Flinn or Educational Innovations)
Spray bottle of ammonia solution
Candle

Safety Precautions
Wear chemical splash goggles, protective gloves and always follow laboratory safety rules while performing demonstrations.

Preparation
Have goldenrod paper off on side of demonstration beaker. Prepare "Gotcha" message by writing message in candle (scrap off excess) on another goldenrod paper.

Demonstration
Explain to students that you are testing a new "top secret" chemical that softens blood vessels so much that one can actually squeeze blood out of your hand. Dip hand into ammonia solution beaker ("the top secret" solution) for a few seconds, remove wet hand onto piece of goldenrod paper conveniently lying on table. Show "bloody handprint", wait a few seconds and pick up prepared goldenrod with message and spray with ammonia solution to make message appear.

Disposal
You can pour remaining ammonia solution back into container to use for this demonstration. Goldenrod paper is also reusable.