There are four important factors affecting the magnetic force of the magnet: one is the number of turns of the coil around the iron core, the second is the strength of the current in the coil, the third is the distance between the coil and the iron core, and the fourth is the size and shape of the iron core.

First of all, it is necessary to understand how the magnetism of the magnet is generated. The magnetic field of the energized solenoid should be B=u0nI according to the Biot-Savart law, where B is the magnetic induction intensity, u0 is a constant, n is the number of turns of the solenoid, and I is the current in the wire, so the magnitude of the magnetic field is determined by the magnitude of the current and the number of turns in the solenoid!

The situation of the iron core is more complicated. The thickness of the iron core should match the number of coils and the size of the current. When the number of coils and the size of the current match the original shape of the iron core, the thickness of the iron core will not have a big impact. At this time, it is impossible to increase the magnetic force of the magnet only by increasing the iron core. That is to say, it is not that the thicker the iron core, the better, nor the thinner the iron core, the better. Also, a horseshoe core is stronger than a bar core because it concentrates the north and south magnetic forces. In our elementary school science class, the thickness of the iron nails has little effect on the magnetic size of the magnet, at least it cannot be determined by the existing equipment.

Studies have shown that the magnetic strength of a magnet is mainly determined by four factors: one is the material of the magnetic core, the magnetic field of the wrought iron core is strong, while the magnetic field of the air core is weak; the second is the number of turns of the coil around the iron core; The strength of the current; the fourth is the interval between the surrounding wire and the iron core. The distance between the wire surrounded by the thick iron nail and the center of the iron core is larger, and the electromagnetic force obtained inside is smaller, and the variables are complex and difficult to measure. It has nothing to do with temperature! The Biot-Savart law should be B=u0nI, B is the magnetic induction intensity, u0 is a constant, n is the number of turns of the solenoid, and I is the current in the wire, so the magnitude of the magnetic field is determined by the magnitude of the current and the solenoid. It is determined by the number of turns of the wire tube!

The size of the magnet's magnetic force is related to (1, the number of batteries in series. 2, the number of turns around the coil). Science Experiment 1 Question: What is the magnetic force of a magnet related to? The assumption is related to the number of coil turns. The larger the coil turns, the larger the magnetic force; the smaller the coil turns, the smaller the magnetic force. What remains the same: the number of batteries, the thickness of the nails, etc. What needs to be changed is: the number of turns of the coil. Conclusion: The magnetic force of the magnet is related to the number of turns of the coil. The larger the coil turns, the larger the magnetic force; the smaller the coil turns, the smaller the magnetic force.