Magic Liquids

Can one solution change color when added to other solutions? This activity uses an indicator to introduce acids and bases. The teacher adds a purple solution to each of three clear liquids. The first liquid turns purple, the second turns red, and the third turns green.


Materials

1 c water

 


1 c water + baking soda

1 c water + vinegar

 


pitcher of cabbage water
(the purple indicator)


What To Do

PLACE the three cups next to each other so the class can see them.

 

 

 

 

ASK the class to predict what will happen if the purple solution is poured into cup 1. Have one student POUR 1/4 c cabbage water into cup 1. The solution turns purple.

 

 

 

ASK the class to predict what will happen if the purple solution is poured into cup 2. Have one student POUR 1/4 cabbage water into cup 2. The solution turns red.

 

 

 

ASK the class to predict what will happen if the purple solution is poured into cup 3. Have one student POUR1/4 cabbage water into cup 3. The solution turns green.

 

 

 

PROMPT the class for questions about this phenomenon, and LIST their questions on the board. REFER to their questions during future lessons on acid and base.What's Happening? Find out more about testing unknown solutions.

Challenge. Using items from your kitchen, create a magic show. Share your favorite ideas in our pH Exchange.

Secret Messages: How can acids and bases be used to write secret messages? 



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