Massachusetts Institute of Technology
Sign in

Breakdown of Air

Grounding rod tips of different sizes are used to discharge a large Van de Graaff generator. The larger the curvature of the tip, the more charge must build up to break down the air, resulting in longer sparks. The electricity ionizes air molecules, releasing quick flashes of light.

A pointed tip barely sparks at all, but instead creates an electric field so strong that it forms a tiny ball of plasma just beyond the tip. This is known as "St. Elmo's Fire", and is just visible when all the lights are turned off.

Comments (0)

It looks like no one has posted a comment yet. You can be the first!

You need to log in, in order to post comments.

MIT Department of Physics Technical Services Group

MIT Department of Physics Technical Services Group

Category: Science | Updated almost 6 years ago

Created
March 03, 2010 12:42
Category
Tags
License
Creative Commons Attribution-NonCommercial (What is this?)
Additional Files


Viewed
35317 times

More from MIT Department of Physics Technical Services Group

Dissectible Capacitor

Dissectible Capacitor

Added over 7 years ago | 00:02:54 | 49234 views

MIT Physics Demo -- Back "emf" in a Large Solenoid

MIT Physics Demo -- Back "emf" in a...

Added over 8 years ago | 00:00:23 | 68564 views

Physics Demo -- Lenz's Law

Physics Demo -- Lenz's Law

Added over 8 years ago | 00:00:28 | 52599 views

MIT Physics Demo -- No-Win Tug of War

MIT Physics Demo -- No-Win Tug of War

Added almost 8 years ago | 00:00:33 | 41513 views

MIT Physics Demo -- Microwave Interference

MIT Physics Demo -- Microwave Inter...

Added 8 years ago | 00:02:11 | 29758 views

Moving Sand Cart Over a Rotating Surface

Moving Sand Cart Over a Rotating Su...

Added almost 7 years ago | 00:01:13 | 36687 views