In the video below, you can find the solution to the chemical riddle involving the food dye and bleach experiment. You can also find a description of how to set up and carry out the experiment. Finally, an extension to the activity is presented. Thanks to Erica Jacobsen, James Hanson, and Alfredo Tifi who all commented with very plausible and/or spot-on explanations for this particular experiment.
What I like most about this experiment is its simplicity. It is easy to set up and equally easy to describe its chemistry. There is no need to balance chemical equations, determine rate laws, draw chemical structures, or calculate reduction potentials. As a result, I have found that even elementary aged students can comprehend the chemistry involved in this demonstration, and they learn a little bit about chemical kinetics along the way!
I have a few more ideas for chemical riddles that I will be presenting in the next few weeks. Do you have any ideas for chemical puzzles that you think folks might find interesting? If so, I’d love to hear from you!
For Laboratory Work: Please refer to the ACS Guidelines for Chemical Laboratory Safety in Secondary Schools (2016).
For Demonstrations: Please refer to the ACS Division of Chemical Education Safety Guidelines for Chemical Demonstrations.
Other Safety resources
RAMP: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies
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Another chemical puzzle riddle idea
Here is another idea for your chemistry riddles, it's borrowed from the master of demos, Prof. Shakahshiri's Battery-Operated Chemical Reaction:
I can give you full details and instructions on how it's done if you want just email me.
All the best,
Great idea, Andres. I will
Great idea, Andres. I will be in touch.