Somewhere inside of every raindrop is a tiny impurity – a touch of salt, a speck of soot, a grain of clay – that’s absolutely crucial to the raindrop’s existence.

LEARN MORE

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To learn more about this topic, start your googling with these keywords:

• Condensation: the process of water molecules glomming together into visible droplets
• Condensation nuclei: tiny solid particles that water vapor condenses onto (also called aerosols)
• Homogeneous condensation: condensation without any kind of condensation nuclei
• Dew point: the temperature below which water vapor starts to condense into droplets
• Heterogeneous condensation: condensation that happens with the help of condensation nuclei
• Critical Embryo: a cluster of water molecules big enough to easily gain more molecules
• Cloud chamber: a cool thing to check out if you want to build a particle detector at home (it involves pumping a bunch of water vapor into pure air; when a particle passes through, it leaves a streak of ionized water molecules that, in super-saturated air, can act as condensation nuclei!)

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CREDITS

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Emily Elert | Script Writer, Narrator and Director Henry Reich | Script Editor Ever Salazar | Illustration, Video Editing and Animation Nathaniel Schroeder | Music

MinuteEarth is produced by Neptune Studios LLC https://neptunestudios.info

OUR STAFF

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Emily Elert • Alex Reich • Henry Reich Peter Reich • Ever Salazar • Kate Yoshida

OTHER CREDITS

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Morning Dew Drops, Slaughter Beach | David Saddler https://www.flickr.com/photos/80502454@N00/5782047749/

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REFERENCES

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Knupp, K. Surface Thermodynamics and Nucleation of Water Droplets and Ice Crystals. Lecture Notes. https://www.nsstc.uah.edu/mips/personnel/kevin/thermo/Chap-9-surfacethermo.pdf

McDonald, JE (1962) Homogenous Nucleation of Vapor Condensation. I. Thermodynamic Aspects. Institute of Atmospheric Physics, The University of Arizona, Tucson, Arizona.

McDonald, JE (1962) Homogenous Nucleation of Vapor Condensation. II. Kinetic Aspects. Institute of Atmospheric Physics, The University of Arizona, Tucson, Arizona.