======Pencils Through a Bag======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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====Summary====                   
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====Procedure====  
  - Fill a resealable plastic bag about two-thirds full of water and seal it tightly.  
  - Hold the bag over a sink, bucket, or outdoors to avoid spills.  
  - Carefully push a sharpened pencil straight through one side of the bag and out the other side.  
  - Try with additional pencils to see how many can be pushed through without leaking.



====Links==== 
The Pencils Through a Bag Experiment - We Are Teachers: 
{{youtube>Ws2Uuuv1mYU?}}\\

Science Behind A Pencil Thru a Bag Full of Water (No Spills!) - SD Lab Rats: 
{{youtube>NMnEUuCatXw?}}\\

📄 Poke but don't Soak - ACS: [[https://www.acs.org/education/whatischemistry/adventures-in-chemistry/experiments/poke-dont-soak.html]]\\



====Variations====
  * Use colored water in the bag to make leaks easier to see.  
  * Experiment with other sharp objects (toothpicks, knitting needles) to compare results.  
  * Measure how many pencils can be pushed through before the bag eventually leaks.



====Safety Precautions====
  * Adult supervision required - pencils and skewers are sharp.  
  * Perform over a bucket, sink, or outdoors to contain spills.




====Questions to Consider====
  * Why doesn’t water leak out of the bag even when pencils poke through it?  
  * What property of polymers allows the bag and balloon to stretch and reseal around the objects?
  * How is the material of the bag different from stiff materials like glass or wood?  
  * Where in everyday life do we rely on flexible, sealing materials like this?