022 – Magnetic probe

Improvised magnetic needle

qualitative magnetic probe

basic experiment about magnetic field lines

paper clip in magnetic field

Introduction to:

Magnetic needle, magnetic field of a bar magnet, magnetic field lines

Material:

• Permanent magnet, e.g. bar magnet
• Safety pin
• Toothpick with one end slightly widened, e.g. by skewering a small piece of cork onto it

Construction and implementation:

Attach the safety pin to the toothpick so that it can rotate freely and hold it near the magnet.

Observation:

The paper clip aligns itself with the magnetic field lines.

Tips:

• Rotating the safety pin by 180° leads to a reversal of the polarity
• There is no need to magnetize the pin prior to the experiment

Explanation:

• The safety pin is ferromagnetic and is magnetised by the magnet.
• It therefore behaves like a magnetic needle and shows the direction of the field lines.