======Floating and Sinking Grapes======


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**Safety: **{{$demo.safety_description}}\\
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**Alternative titles:** Hydrophobic vs. Hydrophilic Grapes
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====Summary====                   
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====Procedure====  
  - Fill a clear drinking glass with soda (any carbonated drink).  
  - Drop one peeled grape and one unpeeled grape into the soda at the same time.  
  - Observe that the unpeeled grape rises to the top while the peeled grape sinks to the bottom.  
  - Discuss why the two grapes behave differently.



====Links==== 
Grapes: Hydrophobic or Hydrophilic? - Culturally Relevant Science: 
{{youtube>1o_hUIDZdrs?}}\\

Grapes - Sinkers and Floaters: Fun Science Experiments - Wilson Middle School Lethbridge Wolverine Productions: 
{{youtube>g2kJ0ku3Ho8?}}\\

📄 Science Experiments - Concept Research Foundation: [[https://conceptresearchfoundation.com/2015/11/12/science-experiments/]]\\


====Variations====
  * Try with different fruits such as raisins, blueberries, or cherries.  
  * Compare results with soda water (no sugar) vs. sugared soda.  
  * Repeat the experiment in plain water to see if grapes float without bubbles.



====Safety Precautions====
  * Avoid spills by performing over a tray or sink.  
  * Do not eat grapes that have been sitting in soda during the experiment.




====Questions to Consider====
  * Why does the peeled grape sink to the bottom? (Without skin, it cannot collect CO₂ bubbles, so its density is greater than the soda.)  
  * Which of the two grapes is lighter in weight? (They weigh about the same, but the unpeeled grape appears lighter because CO₂ bubbles stick to its surface, reducing its effective density.)  
  * What makes the unpeeled grape float? (Its hydrophobic skin allows bubbles to adhere, making the grape–bubble system less dense than soda.)