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Magnetic Strength |
Ever wondered what a Gauss or Tesla was? Read on and wonder no
more.
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| The Measurement of Magnetic Strength
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| Lower strength magnets, normally used for therapy, are perfectly
safe and the products do not have adverse side effects; so users should
not worry about overdosing on magnetic strength. Although patients
with active implants such as heart pacemakers and insulin pumps should
not wear magnets. However it is possible to underdose on strength.
A minimum strength per magnet is required to ensure that the magnetic
field is powerful enough to penetrate through the skin and into the
blood stream.
Carl Friedrich Gauss (1777-1855), a German, was one of the greatest
mathematician of his time. In 1841 he devised the world’s
first magnetic telegraph. He studied the earth’s magnetic
poles (north and south), and devised tables to calculate magnetic
strength.
Nikola Tesla (1856-1943), a Croatian, worked closely with Thomas
Edison in the USA. Tesla later developed alternating current (AC)
systems as distinct from the Direct Current (DC) systems developed
by Edison. Tesla has numerous patents to his credit which are the
basis of many modern day technologies.
The first international standard unit of magnetic measurement was
called the gauss. The SI (Systeme Internationale) measurement of
magnetic flux (strength) was named after Tesla. The Tesla is a much
larger unit than that of gauss, so It is predominantly used in industrial
applications, where very high strength magnets may be used. Tesla
is not an appropriate measuring system for medical magnets as the
calculation of strength has to be represented as milli tesla (1
thousandth of a tesla). However medicine is adopting the SI system
of measurement so it becoming more common to find magnetic strengths
listed in tesla. |
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A Tesla is a unit of magnetic flux density. It is equivalent
to these other units:
1 Weber per square meter
10,000 Gauss (10 kilogauss)
10,000 magnetic field lines per square centimeter
65,000 magnetic field lines per square inch.
One Gauss is about 6.5 magnetic field lines per square inch. If
you place the tip of your index finger to the tip of your thumb,
enclosing approximately 1 square inch, four magnetic field lines
would pass through that hole due to the earth's magnetic field!
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Here is a list of relative strengths of magnetic fields:
| Smallest value in a magnetically shielded room |
10^-14 Tesla |
10^-10 Gauss |
| Interstellar space |
10^-10 Tesla |
10^-6 Gauss |
| Earth's magnetic field |
0.00005 Tesla |
0.5 Gauss |
| Small bar magnet |
0.01 Tesla |
100 Gauss |
| Within a sunspot |
0.15 Tesla |
1500 Gauss |
| Small NIB magnet |
0.2 Tesla |
2000 Gauss |
| Big electromagnet |
1.5 Tesla |
15,000 Gauss |
| Strong lab magnet |
10 Tesla |
100,000 Gauss |
| Surface of neutron star |
100,000,000 Tesla |
10^12 Gauss |
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Most Bioflow magnetic products have 2000 Gauss at the surface.
However, the reason for the effectiveness of the Bioflow magnetic
products is the alternating polarity due to the patented CRP design.
Moving a gauss meter across the inside surface of the Bioflow Elite,
close to one edge the reading is around +350 gauss, in the centre
it peaks at around -2000 gauss, and the field strength returns to
+350 gauss again on the opposite edge. By convention, positive is
North and negative South. In addition to the alternating polarity
of the main magnet, there is also a relay magnet in the buckle,
designed to draw the magnetic field deeper into the wrist. The magnetic
field strength drops off rapidly with distance from the surface.
For optimum benefit the magnet should be close to a blood vessel.
The vein in the centre of the wrist is ideal for this, and many
people are accustomed to wearing a watch or jewellery on their wrists.
Peter Lawrie
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