Or, why can we be magnetically attracted to water and not to magnetism itself?”
The answer is that the force between iron and water is electromagnets. Think of an electromagnet as a spring with a small iron rod stuck through it. When you pull it, you are pulling against it. This action is called the potential to an iron rod. The more force you apply to the rod and the more you pull the rod, the stronger it gets. This force is what is called electromagnets.
The way magnets are generated is by creating an electric field. A field has a source and an output.
The source of the electric field is the metal that is magnetized. As the iron rod is drawn toward the metal, the electric field is increased. When all the iron rods have been drawn toward the metal, the field is no longer strong enough and the field is decreased. This energy is collected. An electromagnetic field of some type is created to maintain the magnetic equilibrium with the metal. The field changes from strong to weak and then back to strong as the rod and metal return to equilibrium.
The amount of kinetic energy generated is determined by the weight of the object in the magnetic field. The more metal there is, the more kinetic energy there is due to the magnetic forces. The more metal there is the less kinetic energy because the objects are smaller!
Magnetic Field Effects
There are several ways that a magnet can affect a structure, such as an iron rod attracting water. A simple way is to pull on the iron rod by holding firmly on a nail, for instance. At the same time the electric field that is created is decreased. The reduced electric field creates a greater magnetic field with a potential lower than normal for iron with a source magnet. As the iron rod falls, it attracts all the water in the area.
Water will also attract a magnet when the current is high and the magnetic field is weakened as we draw towards the iron rod. Water that is attracted by water attracts water.
An example of a structure with water that attracts magnetized iron as well as other things such as a magnet can be seen in Figure 13.
Figure 13. Water attracts iron. Water can repel magnetized magnetized iron. Water attracts iron when the current is high and a weak magnetic field is created. When an iron rod (from which water will also attract) falls, water has attracted it as well as other magnetized objects.