Cloud In a Jar

 

Clouds are made of water. In order for a cloud to form, there must be tiny particles in the air for water to stick to, called condensation nuclei. Follow the instructions below to make a cloud in a jar. Note: always ask an adult for help when using matches.

 

What You'll Need

  • A glass or plastic gallon jar with a wide mouth
  • Hot water (100 mL)
  • Food coloring
  • A rubber glove
  • Matches
  • Large rubber band
  • Flashlight or lamp

Directions

Drawing of Glove in Jar

  • Pour 100 ml of hot water into the jar. Add a drop or two of food coloring to the water.
  • Stretch the open end of a rubber glove over the mouth of the jar, with the glove fingers hanging down into the jar.
  • Place a rubber band around the mouth of the jar to secure the glove.
  • Swirl the water in the jar for about a minute; this allows some water to evaporate into the air inside the jar.
  • Experiment with putting your hand inside the fingers of the glove. Make a fist to pull the glove out of the jar and then push your hand back down into the jar. What changes do you notice inside the jar? Shining a light into the jar might help you see what's happening.
  • Now have an adult light a match. Remove the glove for a moment and drop the lit match into the jar. Quickly seal the jar with the glove and rubber band as before (containing the smoke within the jar). Push your hand back into the glove, down in the jar, and then make a fist to pull the glove out of the jar like before. What do you notice inside the jar this time? 
     

four images showing the steps for the experiment: attach a glove to the mouth of a jar, put your hand inside the glove and make a fist, remove the glove and drop a lit match into the jar, and seal the glove over the jar again to observe a cloud inside the jar.

Be sure to seal the top of the jar completely with the glove. Change the pressure inside the jar by pulling the glove in and out of the jar. Adding some smoke from a lit match to act as condensation nuclei for water droplets to stick to. Use a flashlight to help you see your cloud in a jar.

What's Happening?

In order for a cloud to form, water vapor must be present. Water vapor is created as water evaporates from the Earth's surface, and water is more likely to evaporate as it warms up. Water vapor rises up into the atmosphere where the air is cooler and the pressure is lower. Air pressure changes in the atmosphere allow clouds to form. Pulling the glove out of the jar lowers the air pressure - the same number of air molecules are present but now have more space to spread out. The smoke provides tiny particles, called condensation nuclei, for water molecules to gather on and condense into droplets. This forms a cloud! If the cloud gathers more and more water, eventually a storm will occur. 

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