Final answer:
In Bill Nye the Science Guy, invisible ink was often made with lemon juice, which becomes visible when heated. This chemical reaction is related to the water cycle through the concept of matter changing states, akin to evaporation and condensation.
Step-by-step explanation:
In the Bill Nye the Science Guy show, various substances were used as invisible ink, one common method utilized the reaction between lemon juice and heat. When the lemon juice is applied to paper, it is initially invisible. However, when the paper is heated, the lemon juice oxidizes and turns brown, revealing the hidden message. This type of chemical reaction, which relies on heat, is a nod to the changes in states of matter that are also observed in the water cycle.
The water cycle demonstrates the continuous movement of water on, above, and below the surface of the Earth, which involves processes such as evaporation, condensation, precipitation, and collection. Similarly, the creation and revealing of invisible ink can involve phase changes (liquid to gas when the lemon juice dries and then a chemical change when it is heated). Hence, the concept of invisible ink is connect to the water cycle through the understanding of changes in states of matter and the importance of heat in driving both processes.