Yes - the best and perhaps most intriguing is the...


Electromagnetic Force


R2-D2 says, "Bloop. May the Force be with you. Beep."

"So...what is the electromagnetic force?"

The electromagnetic force is a special force that affects everything in the universe because (like gravity) it has an infinite range. It has the ability to attract and repel charges. Since material in solid and liquid forms are made of charges having a unique order, they, too, may be manipulated by this force. It is also responsible for giving things strength, shape, and hardness. The electromagnetic force can be generated by three types of fields known as the electrostatic field, magnetostatic field, and the electromagnetic field. Some of Earth's greatest philosophers brilliantly used the concept of field lines to help visualize how one object can be moved by another object without actually touching each other. Wow! . . . Force at a distance! Let's see. . .how does this work? Oh, yes, of course! The field lines for static fields are tied to the sources. Static means that the strength and orientation of the source does not change with time. Static electric fields originate from a positive charge and terminate on a negative charge. Static magnetic fields circulate around moving charge (or charges) sometimes called current. They have no beginning or end; they circulate. Because these fields are tied to sources, when the sources are turned off, the field lines disappear and no force is felt. Did you know that the electromagnetic force is responsible for you to have the ability to hold and move things such as your mouse? The electrostatic fields generated among the atoms and molecules near the surface of your hand generate a force field that doesn't allow large objects to pass through your hand. Now you have it! The electrostatic force is responsible for dirt sticking on your hand!

Wait!!! What about the electromagnetic field? The electromagnetic fields are time varying fields containing both electric fields and magnetic fields that feed upon each other even in vacuum! A vacuum is defined as a void of medium. These field lines actually detatch themselves from the source and can exist on their own when the source is turned off. A good example in nature is the light generated from the farthest star. Although we see the light today, it may have been generated millions of years ago! Within that time, the star may have "turned off." This is because electromagnetic energy, such as light, takes time to travel from one point in space to another point in space.

"Is the electromagnetic force really strong?"

It is very strong and this is surprising too because it can work over an infinite range. To give you an idea, the electromagnetic force is approximately 1036 times stronger than the earth's gravitational field! That is (to put it in perspective) 1,000,000,000,000,000,000,000,000,000,000,000,000 times stronger than gravity on Earth! If this was not the case, all material would collapse into a black hole! Forces compete, on Earth the electromagnetic force wins. In a black hole, gravity is a very strong contender.

"What does the electromagnetic force repel and attract?"

The charges create electric fields which drive an electromagnetic force causing unlike charges to attract and like charges to repel. You experience the electromagnetic force when you rub a balloon on your hair and your hair clings to the balloon.

Opposites attract...awww, how cute.Like charges repel.

The pictures above represent opposite charges drawn together and like charges repelling each other via the electromagnetic force. Click on the pictures or refresh the page to have them play again!

Moving charge, in a wire, atom, or molecule generates a magnetic field that circulates. Sometimes, people use the concept of poles to help describe the magnetic field. In this description, like poles repel and unlike poles attract. (check out the magnetism page!)







Frog lifting barbells.

Now that you know something about the electromagnetic force, do you want to go back to...

the four doors of fundamental forces?
the hall of many doors?

Xenon and Fido