======Evaporative Cooling with Water vs Alcohol======


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**Alternative titles:** Comparing Evaporation Rates of Liquids
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====Summary====                   
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====Procedure====  
  - Obtain two thermometers and ensure they are dry.  
  - Wrap a small piece of cotton wool around the bulb of each thermometer.  
  - Soak the cotton wool on the first thermometer with water.  
  - Soak the cotton wool on the second thermometer with methylated spirits.  
  - Place both thermometers in a well-ventilated area, ideally in front of a fan to encourage evaporation.  
  - Record the temperature readings from both thermometers at one-minute intervals.  
  - Continue for several minutes and compare how the temperature drops over time.



====Links==== 
Evaporative cooling experiment - Rachel Peach: 
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====Variations====
  * Test with additional liquids such as acetone or isopropyl alcohol.  
  * Repeat the experiment in different environments (humid vs dry air).  
  * Try using digital data loggers to automatically collect readings.  
  * Compare results at room temperature vs outdoors on a hot day.



====Safety Precautions====
  * Methylated spirits are flammable; keep away from flames, sparks, and hot surfaces.  
  * Use in a well-ventilated space to avoid inhaling fumes.  
  * Avoid skin or eye contact with methylated spirits.  
  * Dispose of alcohol-soaked cotton safely in a sealed container.  
  * Handle thermometers carefully to avoid glass breakage.




====Questions to Consider====
  * Why does methylated spirits cool the thermometer faster than water? (Because it evaporates more quickly, requiring more heat energy from the surroundings.)  
  * How does air movement affect the rate of cooling? (Faster airflow increases evaporation, causing quicker cooling.)  
  * How would high humidity influence the results? (High humidity slows evaporation, reducing the cooling effect.)  
  * What real-life examples use evaporative cooling? (Sweating, cooling in clay water jars, cooling towers.)  
  * How could students present their results to highlight differences between liquids? (By plotting a graph of temperature vs time for water and methylated spirits.)