======Viewing Onion Cells======


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**Alternative titles:** Observing Onion Cells Under Microscope
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====Summary====                   
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====Procedure====  
  - Cut an onion in half and carefully peel away a very thin, transparent layer of epidermis.  
  - Place the onion layer flat onto a clean glass slide.  
  - Gently lower a cover slip over the sample.  
  - Add a drop of food coloring or iodine at the edge of the cover slip and allow it to soak under by capillary action.  
  - Place the slide on the microscope stage and secure it with clips.  
  - Begin viewing with the lowest power objective lens, adjusting the coarse focus until the cells come into view.  
  - Switch to a higher power lens and use the fine focus to clearly see the details of the onion cells.



====Links==== 
Onion Skin Epidermal Cells: How to Prepare a Wet Mount Microscope Slide - Tami Guy, MS, CPPS: 
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ONION CELLS VIDEO - Elizabeth Godwin: 
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📄 How to observe cells under a microscope - BBC Bitesize: [[https://www.bbc.co.uk/bitesize/articles/zbm48mn#zm33f82]]\\

====Variations====
  * Compare onion epidermis with cheek cells to highlight differences between plant and animal cells.  
  * Use different stains (methylene blue) to emphasize various cell parts.  
  * Try preparing slides from different vegetables (garlic, celery) for comparison.



====Safety Precautions====
  * Use caution when handling sharp knives to cut the onion; ask for adult supervision if needed.  
  * Handle glass slides and cover slips carefully to avoid cuts.  
  * Wash hands thoroughly after handling onions and stains.  
  * Avoid getting stains on clothing or skin.




====Questions to Consider====
  * What structures are clearly visible in onion cells that are not seen in cheek cells? (cell wall, sometimes a large vacuole, and rectangular cell shape)  
  * Why is onion epidermis suitable for observing plant cells? (it is thin, transparent, and made of a single layer of cells)  
  * What role does staining play in observing onion cells? (stains make the nucleus and cytoplasm more visible)  
  * How does increasing magnification change the detail observed in onion cells? (it allows visualization of smaller structures but reduces the visible area of the sample)