======Silo of Salt======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Alternative titles:** Grain Pressure in a Mini Silo
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====Summary====                   
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====Procedure====  
  - Cover one end of an empty toilet paper roll with a piece of toilet paper and secure it tightly using a rubber band.  
  - Stand the toilet paper roll upright with the paper-covered end facing down.  
  - Fill about three-quarters of the roll with salt.  
  - Tap the roll gently on the table so that the salt settles evenly.  
  - Hold the roll upright and press a rod or handle slowly down into the salt.  
  - Observe whether the toilet paper at the bottom breaks or stays intact.



====Links==== 
Silo of salt - Experiment Archive: 
{{youtube>soA2W8FOGuM?}}\\

📄 Silo of salt - Experiment Archive: [[https://www.experimentarchive.com/experiments/silo-of-salt/]]\\

====Variations====
  * Replace salt with other granular materials such as sugar, flour, sand, or corn kernels.  
  * Try different amounts of salt (half-full vs. full) to see how it affects pressure on the bottom.  
  * Use a longer or wider roll, such as a paper towel tube, and compare results.  
  * Test the effect of using a pointed versus flat rod tip.



====Safety Precautions====
  * Handle the rod carefully to avoid puncturing the toilet paper too forcefully.  
  * Work over a tray or protected surface to catch any spilled salt.  
  * Avoid pressing hard enough to cause the roll to collapse or tear suddenly.




====Questions to Consider====
  * Why doesn’t the toilet paper break when you press on the salt? (The pressure spreads sideways through the grains, distributing the force over the entire bottom.)  
  * How does this experiment relate to real silos? (In tall silos, pressure increases along the walls rather than just at the bottom.)  
  * What happens when you use larger or heavier grains? (Heavier grains may increase downward force but still distribute pressure to the sides.)  
  * What is saturation pressure, and how can you find it? (It’s the point where increasing the amount of material no longer increases pressure at the bottom.)  
  * Why is understanding this principle important in farming or engineering? (It helps design strong silos and storage tanks that can safely hold bulk materials.)