Heating a magnet: the pin on a thread

Bunsen burner

Drag the burner along the bench. Closed air hole gives the yellow safety flame; open it for the hot blue flame.

Pin temperature

20 °C

The line marks about 770 °C, the Curie temperature of iron and steel.

Magnetic: yes. Held up by the magnet.

Magnet height

Gap between the magnet and the pin when it is held up.

Show the tiny magnets inside the pin

What this shows

The pin is a magnetic material: the magnet induces poles in it and holds it up against gravity. Above the Curie temperature the tiny magnets inside are shaken out of line, the pin stops being magnetic and it falls. As it cools it becomes magnetic again and is pulled back up. Not examined in 0625, but a classic demonstration.

About this lab: Heating a magnet: the pin on a thread

A pin held up by a magnet drops when a Bunsen flame takes it past the Curie temperature, then cools and is pulled back up. Beyond the syllabus.

IGCSE Physics 0625, topic 4.1, simulation 4 of 4. Demagnetisation by heating. Beyond the syllabus

Heating a magnet: the pin on a thread is a free, browser-based simulation for Cambridge IGCSE Physics 0625 (topic 4 Electricity and magnetism, section 4.1 Simple phenomena of magnetism). The course is assessed in Papers 1 and 2 (multiple choice), 3 and 4 (theory), 5 (practical test) and 6 (alternative to practical). There are 0 tabs, each a self-contained experiment with its own controls and live readings, and nothing to install: it runs on a laptop, tablet or classroom projector.

Syllabus coverage

4.1 Describe the forces between magnetic poles and between magnets and magnetic materials, including the use of the terms north pole (N pole), south pole (S pole), attraction and repulsion, magnetised and unmagnetised

4.1 Describe induced magnetism

4.1 State the differences between the properties of temporary magnets (made of soft iron) and the properties of permanent magnets (made of steel)

4.1 State the difference between magnetic and non-magnetic materials

4.1 Describe a magnetic field as a region in which a magnetic pole experiences a force

4.1 Draw the pattern and direction of magnetic field lines around a bar magnet

4.1 State that the direction of a magnetic field at a point is the direction of the force on the N pole of a magnet at that point

4.1 Describe the plotting of magnetic field lines with a compass or iron filings and the use of a compass to determine the direction of the magnetic field

Lessons on this topic: Magnetic poles, attraction, and repulsion, Temporary (soft iron) vs permanent (steel) magnets, Magnetic fields: drawing field lines and using a compass.

How to use this simulation

Use the controls beside the stage to change the set-up and read the live values.

The buttons at the end of the tab strip give the scene the whole window (Full screen, Hide controls) and, on a dark stage, a projector-friendly palette (Light scene). Many scenes also have drag handles: drag them to change the set-up directly.