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======Dry Ice Comet======


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/* GREY BOX INFORMATION - Required                                                                     */
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**Materials: **{{$demo.materials_description}}\\
**Difficulty: **{{$demo.difficulty_description}}\\
**Safety: **{{$demo.safety_description}}\\
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**Categories:** {{$demo.categories}}
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**Alternative titles:** Create a Comet with Dry Ice
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/* SUMMARY - Required                                                                                  */
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====Summary====                   
{{$demo.summary}}


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/* PROCEDURE - Optional                                                                                */
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====Procedure====  
  - Put on gloves and goggles for safety.
  - Crush dry ice into small chunks and powder using a mallet, keeping at least half as powder.
  - Line a large plastic bowl with a heavy plastic bag.
  - Add 1 liter of water, about 2 cups of dirt, and small amounts of starch, corn syrup or soda, vinegar, and rubbing alcohol to the bowl.
  - Stir ingredients together and mix in the crushed dry ice. Observe the white cloud that forms.
  - Gather the bag sides and press the mixture into a clump. Add water as needed until it holds together.
  - Remove the clump from the bag to show the “comet.” Measure its mass and record data.
  - Observe gas jets escaping from the comet surface.
  - Shine a flashlight (the sun) and blow warm air from a hairdryer (solar wind) onto the comet to simulate heating and tail formation.
  - Re-measure the comet’s mass at 5-minute intervals as it melts, up to 30 minutes. Record results.



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/* Links - Optional                                                                                    */
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====Links==== 
Create a Comet With Dry Ice - NASA Video: 
{{youtube>2lk874N7AjQ?}}\\
📄 Create a Comet With Dry Ice - NASA Jet Propulsion Laboratory: [[https://www.jpl.nasa.gov/edu/resources/lesson-plan/create-a-comet-with-dry-ice/]]\\


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/* VARIATIONS - Optional                                                                               */
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====Variations====
  * Compare comet stability with different ratios of water to dry ice.
  * Use less ingredients to make a smaller comet.
  * Use a balance scale to measure more precisely how the comet’s mass changes over time.


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/* SAFETY PRECAUTIONS - Required                                                                       */
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====Safety Precautions====
  * Always wear goggles and thick gloves when handling dry ice.
  * Keep students at a safe distance during crushing and mixing to avoid flying pieces of dry ice.
  * Do not touch dry ice with bare skin—it causes frostbite on contact.
  * Work in a ventilated area to prevent carbon dioxide buildup.
  * Never store dry ice in a sealed container; pressure can cause explosions.
  * Dispose of the comet by placing it in a sink to melt safely.


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/* QUESTIONS TO CONSIDER - Optional                                                                    */
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====Questions to Consider====
  * How does dry ice sublimate differently from water ice as the comet warms?
  * What do the dirt, starch, syrup, vinegar, and alcohol represent in a real comet?
  * Why do comets develop tails when they get close to the sun?
  * How does the comet’s mass change over time, and what does this simulate about real comets?


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/* DEMONSTRATION INFORMATION - Required                                                                */
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/* Complete information in the Demonstration Info box below, following instructions exactly. */