just for fun

[Darren]

what is the best resouce for energy?http://www.amazingmagnets.com/index....ROD&ProdID=108

[Wise Young]

Originally Posted by Darren

what is the best resouce for energy?http://www.amazingmagnets.com/index....ROD&ProdID=108

This is link describes an interesting ferromagnetic fluid, i.e. a fluid that attracts iron. While I am not sure how it relates to energy (because strictly speaking magnetism is a force like gravity and is not energy), the fact that a fluid can be magnetic is contradicts much of what I had understood about magnetism. A magnet occurs when particles that positive and negative magnetic poles line up in a solid so that a directional magnetic field is present.

So, I decided to look it up. According to Wikepedia (Source):

A ferrofluid (from the Latin ferrum, meaning iron) is a liquid which becomes strongly polarised in the presence of a magnetic field. It is a colloidal mixture comprising extremely small magnetic particles suspended in a synthetic oil. The particles are coated with a soap or detergent to prevent them from clumping together.

Ferrofluids are composed of nanoscale ferromagnetic, or ferrimagnetic, particles suspended in a carrier fluid, usually an organic solvent or water. The ferromagnetic nano-particles are coated with a surfactant to prevent their agglomeration (due to van der Waals and magnetic forces). Although the name may suggest otherwise, ferrofluids do not display ferromagnetism, since they do not retain magnetization in the absence of an externally applied field. In fact, ferrofluids display (bulk-scale) paramagnetism, and are often referred as being "superparamagnetic" due to their large magnetic susceptibility. Permanently magnetized fluids are difficult to create at present.[1]

It is important to note the difference between ferrofluids and magnetorheological fluids (MR fluids). The particles in a ferrofluids primarily consist of nanoparticles which are suspended by Brownian motion and generally will not settle under normal conditions. MR fluid particles primarily consist of micron-scale particles which are too heavy for Brownian motion to keep them suspended, and thus will settle over time due to the inherent density difference between the particle and its carrier fluid. These two fluids have very different applications as a result.

Interesting. The following is a quantity of ferrofluid on glass with a magnetic underneath.


Wise.