2B30.10 • Impossible Drinking Straw

Photo shows the demonstration used at the University of Texas at Austin.

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Instructions / Notes:

• The demonstration shows the pressure of water is height dependent (P = Patm + ρgh.
• Set the 32-foot straw vertically and attach a new mouthpiece.
• Place the tip of the straw to the bottom of the cup.
• Try to sip liquid using a 32-foot vertical straw.
• Result: The liquid will come up through the straw up to a certain point, but it doesn't reach the end of the straw, so that person cannot drink water inside of the cup.

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Demo Staff:

• Remove and discard the used mouthpiece after each use.
• Provide a new mouthpiece for every request.
• Color the water to observe liquid movement.

Last updated on October 23, 2025