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: Charging by Contact
Categories: Lab/Student Activity, Teacher Demonstration
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
Teacher Demo: Chemiluminescence
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
Teacher Demo: Eggmosis
Categories: Teacher Demonstration
Osmosis is the process by which the concentrations of two solutions equalize across a selectively permeable membrane. Osmosis is necessary for the digestive and excretory systems to function. This... read more