Even though Earth is a globe, a compass doesn't look at the physical shape of the planet to find direction. Instead, it relies on an invisible, global force: Earth’s magnetic field. Here is how a compass interacts with our planet to point the way: 1. Earth’s Molten Core Acts Like a Magnet Deep beneath our feet, Earth's outer core consists of swirling liquid iron and nickel. Because this massive ocean of metal is constantly moving and conducting electricity, it generates powerful electrical currents. This dynamo effect turns the entire planet into a giant bar magnet with its own magnetic field, stretching out into space in a region called the magnetosphere. 2. The Compass Needle Follows Field Lines A traditional compass contains a small, lightweight, freely pivoting magnetized metal needle. Magnetic fields have invisible lines of force that loop around the planet from one magnetic pole to the other. Because opposites attract, the North-seeking pole of the compass needle is naturally drawn to align itself with these magnetic field lines, pointing toward the magnetic region near the top of the globe. 3. Magnetic North vs. Geographic North One fascinating detail is that a compass doesn't actually point to the true geographic North Pole (the axis upon which the Earth spins). Geographic North is fixed at the top of the globe (latitude 90°N). Magnetic North is a shifting location where Earth's magnetic field points straight down into the ground. It currently sits hundreds of miles away in the Arctic. Navigators must account for this difference—known as magnetic declination—depending on where they are standing on the globe to get an accurate reading. Would you like to know how modern GPS technology differs from a traditional magnetic compass when navigating?