Scienceville
Magnets
Earth acts like a giant magnet, turtles use magnetism to find their way, and the magnetic north pole keeps wandering! Let's explore the invisible pull of magnetism.
Did you know?
The word 'magnet' comes from 'stone from Magnesia', a place in Anatolia (in today's Türkiye) where natural magnetic rocks called lodestones were found. People in Anatolia, India and China wrote about magnets about 2,500 years ago.
Earth itself acts like a giant magnet! Deep inside, hot liquid iron and nickel in Earth's outer core keep moving, and this makes Earth's magnetic field. It is as if a huge bar magnet were hidden inside our planet.
Earth's magnetic north pole, which compass needles point towards, keeps moving! It was first located in 1831. In early 2019, it was moving about 55 km a year, away from northern Canada towards Siberia.
Try this: Make a Water Compass
Do this with an adult
With an adult, stroke a steel sewing needle with one end of a bar magnet 30 times, always in the same direction. Lay the needle on a small flat leaf floating in a bowl of water. Watch it slowly turn to point north and south! Keep small magnets away from little brothers and sisters: swallowing magnets is very dangerous.
Go further: Animals with a Built-in Compass
Many animals can sense Earth's magnetism and use it to find their way. Experiments show that young loggerhead sea turtles use Earth's magnetic field as a compass to choose their direction. Homing pigeons use it as part of their navigation: when scientists fixed magnets to some pigeons' backs, the birds got confused! European robins and salmon can also sense direction with it. Scientists are still discovering exactly how this hidden sense works.