This specimen of Lodestone is only a couple of cm long. It is a magnetic rock called magnetite used as one of the earliest compasses. Here it is shown with some iron filings attracted to to it. This also shows the areas of greatest magnetisation.
“Continue Reading” to see mapping of fields, more lodestone projects, a compass and links…
Continue reading
Singing magnets are magnets that make a peculiar sound when they crash together under magnetic attraction. They are ovoid magnets can be bought in novelty stores and eBay for less than $10. Also known as rattlesnake or buzz magnets. They might make an interesting amusement as a present for the geek in your life.
“Continue reading” for a video and slo-mo effect and how to throw them. Plus links…
Continue reading
Iron filings, magnetic viewing film or ferrofluid can all make magnetic field lines visible. Isolated readings can be also taken with gauss meters. Sure there are some nice computer graphics of predicted fields and the earth’s fields. But what about around other places such as large irregular magnets or even the earth’s magnetic field lines in your back yard for example?
“Continue reading” for more effects photos, the electronics, program and links…
Continue reading
Sail a magnetic sea with diamagnetic levitation. Diamagnetism causes pyrolytic graphite to levitate. This floats around with less than 1 mm gap above a 13 x 13 array of 5 mm magnets. The north poles are marked as black and the square sheet is 45 mm a side and 0.5 mm thick (20/1000 inch). The video shows the sheet sliding around without friction when I tilt the base slightly.
“Continue reading” for a video, close ups, more explanations and links…
Continue reading
Magnetic repulsion demo. You can’t push them together. This is a popular demonstration of magnetic repulsion. You try to bring the North poles of these magnets together but physically can’t. You start feeling the invisible field at about 10 cm and it becomes stronger than you are at about 2 cm. It is a spooky feeling.
For more details with 5 photos and links:
Coin shrinking a Japanese coin to half its diameter while preserving details. Bonsai for coins. You can still see the Japanese characters miniaturized on this one yen coin. “Continue reading” for the details of the huge currents involved to make small change. Continue reading
To demonstrate levitation by induction, I have cut down a large transformer to allow an external field. It was 240 V to 110 V and rated at 2 kVA. I use the two windings in series. When run from DC it draws 15 A at 30 V or 450 W. This is enough to levitate a large NIB magnet about 17 cm away. This simple arrangement is not able to give stable levitation however but demonstrates the field strength.
“Continue reading” for further views and explanations. 4 photos and links…
Continue reading
Here is my attempt at measuring magnetic field strength. To measure the field generated by the electromagnet above I made a coil that could be placed in the magnetic field.
“Continue reading” for measurements and results. 3 photos and links. Continue reading
Electromagnets don’t come bigger than this at my place. A big soft iron cored electromagnet is supporting a drill by the spade bit between the pole faces.
“Continue reading” for power levels and further information plus links…
Magnetic viewing film allows one to visualise magnetic fields easily. Of interest is the segmented field from the top magnet which is not apparent by just looking at it. The old AlNiCo bar magnet on the left has a very distorted field.
“Continue reading” for other examples, 4 photos and links.
Continue reading