Chemical Mystery #15: The Leaky Cup

A cup full of water...but it doesn't leak!

Time for a new chemical mystery! Watch the video below and see if you can use your chemical knowledge to figure out how this experiment is done.

My guess is that this trick will be easy for the chemistry teachers to figure out. However, I'll bet this experiment will stump most of your students! Let me know in the comments how you think I carried out this trick. I'll post the solution in a few days.

Watch the !

Safety

General Safety

Please refer to the ACS . Some additional information on these guidelines can be found in a .

Safety resources

: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies

 

NGSS

Constructing explanations and designing solutions in 9–12 builds on K–8 experiences and progresses to explanations and designs that are supported by multiple and independent student-generated sources of evidence consistent with scientific ideas, principles, and theories.

Summary:

Constructing explanations and designing solutions in 9–12 builds on K–8 experiences and progresses to explanations and designs that are supported by multiple and independent student-generated sources of evidence consistent with scientific ideas, principles, and theories. Construct and revise an explanation based on valid and reliable evidence obtained from a variety of sources (including students’ own investigations, models, theories, simulations, peer review) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future.

Assessment Boundary:
Clarification:

Students who demonstrate understanding can plan and conduct an investigation of the properties of water and its effects on Earth materials and surface processes.

More information about all DCI for HS-ESS2 can be found and further resources at.

Summary:

Students who demonstrate understanding can plan and conduct an investigation of the properties of water and its effects on Earth materials and surface processes.

Assessment Boundary:
Clarification:

Emphasis is on mechanical and chemical investigations with water and a variety of solid materials to provide the evidence for connections between the hydrologic cycle and system interactions commonly known as the rock cycle. Examples of mechanical investigations include stream transportation and deposition using a stream table, erosion using variations in soil moisture content, or frost wedging by the expansion of water as it freezes. Examples of chemical investigations include chemical weathering and recrystallization (by testing the solubility of different materials) or melt generation (by examining how water lowers the melting temperature of most solids).

Join the conversation.

Comments 4

Chad Husting's picture
Chad Husting | Wed, 05/22/2019 - 07:56

Tom - Love your demos.  This would make a great first day demo.  Just guessing....don't want to give it away...does the answer involve possibly a polymer?  If I'm right do I win a prize?  Barring a family emergency, I hope to be at ChemEd in Naperville.  Hope to see you there!

Tom Kuntzleman's picture
Tom Kuntzleman | Wed, 05/22/2019 - 17:44

Hi Chad:

You are absolutely correct - the experiment involves a polymer! Hmmm....giving out prizes would be a great idea. Do you have any ideas as to what we could give away? I look forward to seeing you at ChemEd this summer, too. Are you presenting on anything?

Tom

Tom Kuntzleman's picture
Tom Kuntzleman | Wed, 05/29/2019 - 07:09

Michael: Thanks for sharing the video...I loved it! I knew I'd have a hard time fooling chemistry teachers with this particular chemical mystery, and it looks like you were no exception.