Small magnetic needle for color projection
A magnetic needle is a compass. Compass is one of the four great inventions in China. In the present physics teaching, a small magnetic needle can be used to judge the direction of the magnetic field. However, the magnetic needles sold in the market or investigated and dialed by higher authorities are inconvenient to use. When the teacher was doing a demonstration experiment in the direction of magnetic field, the students couldn't see clearly below, so the teacher had to take the instrument down and show it to the students one by one. What should I do? After trying their best, the students finally made a simple color projection magnetic needle, which can be used as a compass and projected on the projector, so that the whole class can see the direction of the magnetic field, which provides great convenience for teaching experiments.
The invention has simple structure and common materials. It is made of snap-in steel needles, pins, plexiglass strips and transparent projection film materials. The manufacturing method is as follows: put two steel needles on the two steel needles respectively, and the two steel needles should be balanced. Then cut the transparent film into long, pointed pieces and stick it on the steel needle with 502, one piece at each end should be symmetrical. Then the upper part of the magnetic needle is painted red and green respectively. Polished into a round base for magnetic needle, with iron in the middle of a round plexiglass. Note that the latch should be perpendicular to the base. The inner groove of the small buckle is used as the bearing support hole for rotation. Put the bearing on the needle tip, so that the magnetic needle will rotate on the needle tip. The last one is to wipe the S pole of the bar magnet from the middle part of the magnetic needle to the green side, and magnetize the small magnetic needle, which is the N pole. In this way, the small magnetic needle will be magnetized.
Put the self-made small magnetic needle on the projector, and you can see the direction of each point of the magnetic field at a glance from the curtain.