Uploaded May 2025 | Updated September 2026, 2 weeks ago

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This video shows the result of thorium going through "alpha decay", emitting a positively charged helium nucleus ("alpha particle"). Surrounding the thorium metal rod is saturated isopropyl alcohol vapor. The positively charged alpha particles given off by the thorium act as condensation nuclei for the alcohol vapor. The small white lines are composed of small droplets of alcohol, showing the path of the nuclear decay product.