Magnetic field meter. Drawing, description

CHILDREN'S SCIENTIFIC LABORATORY
Free library / Directory / Children's Science Lab

Magnetic field meter. Children's Science Lab

Children's Science Lab

Who has not seen how the magnetic needle of a compass, swung several times from side to side, is set in such a way that its ends point exactly to the magnetic poles? This magnetic field of the Earth causes it to line up along its lines of force, thereby indicating their direction. However, accurate quantitative measurement of the terrestrial magnetic field is still inaccessible to this day. On special ships made of non-magnetizable materials, scientists sail into the open ocean - where the Earth's magnetic field is least distorted by surrounding metal objects or natural ore deposits - to make accurate measurements. And yet, an approximate determination of the strength of the earth's magnetic field can be done right in the lesson without leaving the classroom. To do this, you need to make a device that was designed by the guys from school number 7 in the city of Vilnius.

(click to enlarge)

The device is quite simple (see figure). On a light frame made of aluminum measuring 12,0x16,0 mm, mounted on an axis with low friction (simply on two needles), n = 100 turns of insulated wire with a diameter of 0,1 mm are wound. The ends of the winding are soldered to two brackets fixed on the frame and isolated from it. The beginnings of spiral

springs. An arrow is rigidly attached to the frame, showing on a scale with divisions in degrees the angle of deviation of the frame from the initial equilibrium position. The end of the upper spring is soldered to the corrector lead, which can rotate around the axis installed in the bracket. The bracket is attached to a plexiglass scale with degree divisions. When the corrector is turned, the spring is twisted or untwisted, due to which the frame with the arrow is rotated, which allows you to set the arrow to zero of the reference angle. For the device, a box is made of plexiglass or other materials whose magnetic permeability is close to unity.

Before starting measurements, it is necessary to establish a quantitative relationship between the moment of forces relative to the axis of the frame and the angle of its rotation. To do this, the device is installed so that the arrow and the axis of the frame are in a horizontal position. At some distance from the axis, for example 10 mm, a small load is hung on the arrow, for example, a ring of wire weighing 0,01 g. The torque will be equal to:

M=F*L=0,000098 H*0,01 m=9,8*10^-7 n*m. Let the arrow turn at the angle A=40°. Then the coefficient of proportionality between the moment of forces and the angle of rotation will be equal to:

K=M/A=(9,8*10^-7n * m) / (40 degrees) \u2,45d 10 * XNUMX^-8 n*m/deg

To work with a magnetic field, it is necessary to assemble the following electrical circuit (see figure). In series with the device, connect a milliammeter, a high-resistance rheostat, a switch and a battery from a flashlight. Determine in advance the direction of the magnetic field lines with a compass and hold the device throughout the experiment so that the frame is parallel to them. Turn on 30mA current. As is known from the school physics course, the moment of forces of rotation M, acting on a frame with current I and area S, is equal to: M = B * I * S, where B is magnetic induction. Let the frame deviation be 4°. At the same time, M \u4d K * 2,45 ° \u10d XNUMX * XNUMX^-8 n * m / deg * 4 deg \u9,8d 10 * XNUMX^-8 n*m.

From here we get the value of magnetic induction:

B=M/(I*S*n)=(9,8*10^-8n * m) / (0,03a * 1,92 * 10^-4м²*100)=1,7*10^-4tl.

The scale of the instrument can be graduated in Tesla. The device can measure the magnetic induction of not only the earth's field, but also the fields of permanent magnets, conductors and coils with current,

Author: G. Grigenas

We recommend interesting articles Section Children's Science Lab:

▪ Geyser at home

▪ air wheel

▪ Under pressure

See other articles Section Children's Science Lab.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive

Intel Centrino Technology 25.01.2004

Intel Centrino Technology for Mobile Personal Computers is Intel's first technology designed specifically for the mobile world.

This latest technology combines built-in wireless networking with superior mobile PC performance. It also provides extended battery life and allows you to create compact laptops that are easy to carry around.

Other interesting news:

▪ Monitor NEC MultiSync LCD-X474HB with a brightness of 2000 cd m2

▪ Superelastic alloy that maintains rigidity at high temperatures

▪ Our galaxy will be sewn by a cloud with a magnetic shield

▪ New video discs store up to four hours of video on each side

▪ Mouse left

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Low frequency amplifiers. Article selection

▪ article Ezhe pisah, pisah. Popular expression

▪ article What is yellow fever? Detailed answer

▪ article Instructor of the security organization service. Job description

▪ article Refinement of the DPKD of the RA3AO transceiver with an arbitrary IF. Encyclopedia of radio electronics and electrical engineering

▪ article Protection of the telephone line. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews