An unseen field attracts magnetically sensitive items with its magnetic pull. Magnetic fields can be classified in various ways depending on the situation. As the distance between the magnet reduces, its strength grows, and as the distance increases, it diminishes. Only at a certain distance from the magnet does a magnetic field exist. The iron nail gets drawn toward a bar magnet even though they are not in direct touch. Any magnet generates its magnetic field, can communicate with other magnets, and even attract magnetic materials. What is a Magnetic Field?Ī magnetic field is an area around a magnet where the magnet’s magnetism is active. Any magnet produces a magnetic field that attracts other magnetic materials. Magnetic poles with similar magnetic poles attract one another, while poles with opposite magnetic poles repel each other.

All magnets, regardless of size, have two poles: north and south magnetic poles. Small fridge magnets, speakers, computer devices, and even medical equipment like magnetic resonance imaging (MRI) scanners contain them. Magnets are used in a variety of ways and have umpteen applications. The density of the lines indicates the size of the field, with more density at the poles (where the field is strong) and less density as they move away from the poles. It is strongest at the poles and weakest at the equator.Endless lines of force (or magnetic flux) that originate from the north-seeking poles of a magnet and join south-seeking poles can be used to illustrate magnetic fields.

Intensity: The magnetic field also varies in strength over the earth's surface.

This angle ranges from 0 degrees at the equator to 90 degrees at the poles.

Inclination angle: The angle at which the magnetic field lines intersect the surface of the earth.

Hatchling loggerheads have also been shown to detect magnetic field intensity. Although intensity varies somewhat less predictably than inclination, the general trend is that the field is strongest near the magnetic poles and is weakest near the equator. As we will discuss, hatchling loggerheads have been shown to have this ability.Ī second geomagnetic parameter that varies across the surface of the Earth is the strength or intensity of the field. As a consequence, an animal that has the ability to distinguish between magnetic inclination angles has a mechanism that it might be able to use to approximate its latitude. Thus, inclination angle varies with latitude. At the magnetic pole, the field lines are directed almost straight down into the Earth and the inclination is said to be 90°.

As one travels north from the equator, however, the field lines become progressively steeper. On the diagram above, note that near the equator, the field lines are approximately parallel to the Earth's surface the inclination angle in this region is said to be 0°.

For example, at each location on the Earth, the field lines intersect the Earth's surface at a specific angle of inclination. Several features of the Earth's field vary in a predictable way across the surface of the globe and might, in principle, be used in assessing geographic position. The field lines emerge from the southern half of the earth and re-enter in the northern half.

To a first approximation, the Earth's magnetic field resembles that of an enormous bar magnet.

Magnetic fieldlines