In this demonstration, a chemical reaction is used to make a hidden message visible. The demonstration illustrates an entertaining application of chemical reactions in toys and everyday objects. It is also an interesting way to start the discussion of acids and bases, the pH scale, or acid-base indicators. Invisible ink has been used in espionage to send messages that cannot easily be read by enemies.
Related Resources:
Teacher Demo/Student Activity: Elephant's Toothpaste
Categories: Lab/Student Activity, Teacher Demonstration
This demonstration is an entertaining way to introduce simple chemical reactions and the types of evidence that indicate the occurrence of chemical change, including the production of a gas. A link... read more
Student Activity: Counting Atoms and Molecules
Categories: Lab/Student Activity, Teacher Demonstration
Chemists are constantly faced with the daunting task of counting large numbers of items, specifically atoms, ions, molecules and compounds. This task is made even more difficult by the fact that not... read more
Teacher Demo: The Nose vs. the Wrecking Ball
Categories: Teacher Demonstration
A pendulum is constructed from a 1.0-kg mass suspended from the ceiling, with a length of strong string long enough so that, when pulled about 40o from the vertical, the mass comes to nose level. The... read more