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.
In this demo, a polyethylene strip is charged by rubbing with wool. The charged strip is then used to charge a neutral object, a pith ball, by contact. This demo can be done as a student activity. read more
Categories: Teacher Demonstration
This demonstration is definitely an eye-catching crowd-pleaser. It is a great demonstration to show the interconnection between physics and chemistry, linking an example of light emission to evidence... read more