Monday, October 31, 2011

Demonstrating a Chemical Reaction -- Post #42

My grade nine applied science class is currently studying a unit on chemistry.  We have learned the types of evidence for a chemical reaction occurring (colour change, bubble, heat / light, formation of precipitate).
In this demonstration of “elephant tooth paste” we are looking for evidence that it is a chemical reaction. In the first video you will note that the reaction is not impressive. In the second video the reaction is more impressive and the students are more engaged.

Listen to the questions that are being generated by the students!

Allowing the students to record the reaction with their own electronic devices allows them to replay the activity over for friends and family, each time they watch it their learning is reinforced!
To make elephant toothpaste:
1.       Put 50 mL H2O2 into a 1000 mL graduated cylinder Add about 20 ml liquid soap
2.       Swirl
3.       Add a few drops of food colouring (optional)
4.       Add about 10 mL KI (catalyst)
5.       Stand back!
Which one of the student generated questions or comments impressed you the most? Leave your reply in the comment box below!

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