|Three vessels with magnets on rods. Each vessel contained different sized|
particles of iron, yet the magnet near each vessel was the same size and strength.
The purpose of the exhibit was to learn how the particles behave in the presence of the magnet. For the interest of conservation and understanding more about iron particles, this was a wonderful activity to see!
Below is the image of the iron particles that are considered "nano" size or 100 nanometers or 0.1 microns. In the presence of the magnet, the particles are all clustered together very near the magnetic field. As the magnet moves up the vessel the particles stay together following the magnet and traveling easily together in a tight group.
The image below shows a larger size particle, called "magnetite sand" at 1,500,000 nanometers. These particles followed the magnet as it moved up and down on the rod, but did not remain as a tight group. These particles are so small they have fewer magnetic regions that can align to be attracted to the magnet. More about domains can be read in a previous blog post "Magnets are only as strong as ....".
Next is "magnetite powder", at 3,000 nanometers. These particles only slightly are attracted to the magnets. These particles are hardly attached to the magnetic field force. They really just want to sit at the bottom of the container.