Magnetic data storage model experiment
- Audio and video tapes
- Hard drives in computers
- Data strips on ATM cards or on parking tickets
- Security labels on CDs or DVDs from the library
Why a model experiment?
- We use a permanent magnet for recording. In technology, this role is taken on by a tiny electromagnet with adjustable field strength.
- In the experiment the foil remains still and the recording magnet is moved. In technology it is the other way round.
- Data on the flux foil is legibly for people. On an audio or videotape and on hard drives on the other hand, a microscopically small area is newly arranged during recording and put in complete disarray during erasing. Even under an electron microscope this data is not legible for us (see picture 2).
- We read with our eyes and our brain. "Read heads" in technology are electromagnets, in which the magnetic field that is moved past them creates a tension (through induction - like in a bike dynamo).
- The flux foil contains movable nickel particles cast in gel, which reflect the light in different ways depending on the arrangement. Magnetic storage media in technology contain glued iron or chromium nickel particles, on which magnetic areas (so-called Weiss domains) rearrange themselves.