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 over 6 years ago

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


Viewed
36795 times

More from MIT Department of Physics Technical Services Group

Physics Demo -- Magnetic Motor

Physics Demo -- Magnetic Motor

Added almost 9 years ago | 00:01:29 | 78579 views

MIT Physics Demo -- Pendulum and Magnet

MIT Physics Demo -- Pendulum and Ma...

Added almost 9 years ago | 00:01:11 | 47775 views

Center of Mass Trajectory

Center of Mass Trajectory

Added almost 8 years ago | 00:01:30 | 55634 views

Monkey and a Gun

Monkey and a Gun

Added over 8 years ago | 00:01:16 | 73959 views

Ripple Tank: Single and Double Slit Diffraction and Interference

Ripple Tank: Single and Double Slit...

Added over 7 years ago | 00:03:05 | 63218 views

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

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

Added almost 9 years ago | 00:00:23 | 70242 views