======Scattering of Light with Milk======


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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Alternative titles:** Why is the Sky Blue?, Sunset in a glass
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====Summary====                   
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====Procedure====  
  - Fill a clear glass pitcher or tall jar with water.  
  - Add small amounts of milk until the water appears murky but still translucent.  
  - Place a flashlight at the bottom or side so its beam shines through the mixture.  
  - Observe the light from the side of the pitcher (90° to the beam); it should appear bluish.  
  - Observe the light from the far end of the pitcher (180° to the beam); it should appear red-orange.  
  - For better visibility, project the light onto a white index card and perform the experiment in a dark room.



====Links==== 
Refraction of light during the transition from air to water made visible with milk - physikdigital • de: 
{{youtube>K5JvfcjSKV0?}}\\

Scattering of Light Using Milk - Science Made Easy: 
{{youtube>2zcKdlzxFzw?}}\\

📄 Sunset in a glass - Causes of Color: [[https://www.webexhibits.org/causesofcolor/14F.html]]\\


====Variations====
  * Use a long, narrow aquarium to make the effect more dramatic.  
  * Compare results using whole milk, 2% milk, skim milk, or milk powder.  
  * Try adjusting the concentration of milk to change how much scattering occurs.



====Safety Precautions====
  * Perform the experiment on a stable surface to avoid spills.  
  * Avoid getting water or milk on the flashlight or electrical components.  
  * Clean up spills promptly to prevent slipping hazards.




====Questions to Consider====
  * Why does the sky look blue during the day but red at sunset? (Blue light is scattered in all directions by air molecules; at sunset, light travels farther through the atmosphere, scattering away most of the blue and leaving red-orange light.)  
  * Why does violet light not dominate the sky even though it has a shorter wavelength than blue? (The sun emits less violet light than blue, and our eyes are less sensitive to violet wavelengths.)  
  * How does the milk in the experiment represent Earth’s atmosphere? (The fat and protein molecules in milk scatter light, similar to how gases and dust scatter sunlight.)