# What is meant by the horizontal component of the Earth's magnetic field?I found this horizontal component in a chapter about magnetism. I know it is something about the magnetic field of Earth but...

What is meant by the horizontal component of the Earth's magnetic field?

I found this horizontal component in a chapter about magnetism. I know it is something about the magnetic field of Earth but what it exactly is and why is it said so?

### 1 Answer | Add Yours

The magnetic field lines of the Earth resemble those of a bar magnet. If we imagine the Earth has a bar magnet pointing to the north and south poles we can begin to imagine the shape of the field lines in various places. At the equator they are parallel to the Earths surface or horizontal and the only component is a horizontal component. At the poles the field lines are vertical - they point straight down-and there is no horizontal component. At latitudes in between the field lines are at an angle to the Earths surface. It is possible to represent field lines with VECTORS, imaginary arrows which show size and direction. Try to imagine a one metre arrow resting at an angle on the floor. Imagine a shorter vertical arrow sticking up from the same point on the floor and a shorter horizontal arrow lying on the ground with its tail end touching the tail ends of the other two. Now imagine that the vertical and horizontal arrows have lengths that can be added together according to Pythagorus' theorem to equal the length of the sloping arrow. The horizontal arrow is the HORIZONTAL COMPONENT of the Earths field at the point.