We know how heavy something that cannot be seen is

The problem with answering how much you currently weigh lies in the question itself, because It does not specify what we mean by current. It is – as this term is commonly used – the amount of energy expressed in joules or kilowatt-hours, or perhaps the liquid means the electrons whose movement is responsible for generating an electric current? On the one hand, it may seem unimportant This type of fallacy may lead to situations in which mass and weight are confused when talking about “body weight” in kilograms.although in fact Newton should be used.

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Current as the movement of electrons

By scientific definition (simplified) Electric current is the regular movement of electrical charges (electrons). We deal with this pattern not only in batteries or accumulators (where electrons flow from positive to negative), but also in the electrical grid that we all use every day. In this understanding of current, the movement of electric charges is importantnot the electrons themselves, although density (the list of charges flowing at a given time) and potential (the energy of each element) are of course important.

If we think of the current as electrons flowing from one place to another, we cannot determine how much the current weighsBecause we are talking about the activity of all these loads, not about their mass. Therefore, the electric car battery is half discharged This will not lose weight, which will allow you to drive faster with the same engine load. The same goes for smartphone batteries – if you weigh a fully charged phone and then a dead phone, you'll get the same result every time.

This happens because electrical charges do not magically “escape” from the battery, but rather move – as we mentioned previously – in an organized manner from plus to minus, i.e. They move from one end of the system to the other. Everything remains within one device and its mass does not change.

However, electrons are responsible for generating current in conductors, and electrons have their own mass, so can they be calculated?

A diagram of an atom around which electrons orbitImage: Spectral Design/Shutterstock

A diagram of an atom around which electrons orbit

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Current as a quantity of energy

You may remember from physics lessons that an electron has an electric charge expressed in coulombs, a Its value is −1.602176634 × 10^-19 degrees Celsius. This quantity is closely related to mass, but one electron weighs only a small fraction of a kilogram (about 9.1 x 10^-31 kg), so Even if billions of electrons moved from one place to another, their value would be negligible.

outlet

outlet

The other case is the use of the term “current” according to a common but imprecise definition. Then it comes down to it The amount of energy consumed by equipment (such as a television) in a given unit of time. We use joules (J) or kilowatt-hours (kWh) to determine this – how much “current” can we find in 1 kilowatt-hour? The formula that links mass and energy is of course the well-known formula:

1 kilowatt-hour equals 3.6 million joules (a lot of energy!), so if we convert the above formula appropriately to calculate the mass, we get 0.00004 kg. Therefore, one kilogram of “electricity” requires up to 250 thousand. kilowatt hours. is this too much? Yes, that's a lot of energy, so for one person using small amounts of it every day, Both the weight of electrons as electrical charges and the weight of “current” understood as electrical energy are negligibly small.

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Is it possible to weigh the current? The current scale was created more than 150 years ago

Now that we know that depending on how we understand the word “current”, the answer to the question in the title of this entry will be different, Out of curiosity, I'll mention an interesting device called a current meter. They were created by William Thomson (also known as Lord Kelvin, co-author of the systems without which there would be no modern heat pumps), a British scientist who lived in the years 1824-1907. Was it possible to weight the current with this?

Lord Kelvin current scalePhoto: Eric Chalov / Wikipedia / Public Domain

Lord Kelvin current scale

Well, no. This equipment was used as specified in the book “Electrical measurement”:

This means that as the standard for many years was the platinum and iridium cylinder from Siver (this changed in 2019), Lord Kelvin's meter allowed him to measure a current of exactly one ampere.

The device worked as follows – the weight of a given block was attached to one end of the scale Only the force of gravity, depending on mass and gravitational acceleration, should act. Two coils are attached to the other side (one fixed and one movable located inside the first coil). Both the elements are connected in series and an electric current flows through them. When the electric charges began their journey, the moving coil generated an electrodynamic force.

The current scale is at the National Museum of Nature and Science in TokyoPhoto: Momotaro 2012 / CC BY-SA 3.0/ Wikipedia

The current scale is at the National Museum of Nature and Science in Tokyo

This is balanced by the force acting on the weight, so… If equilibrium occurs, the current in the system can be determinedKnow the exact mass of the element on the first arm and the value of the so-called “c” factor, taking into account the dimensions of the coils. And here was the problem, because One major disadvantage of the current meter is that the accuracy of the current measurement is limited by the coil measurement accuracy and their mechanical stiffness..

However, apart from the disadvantages of the described device – we could not use it to weigh the current, because It's a current metric, not a current metric. The second piece of equipment must measure exactly how much weight the electrons (electrical charges) produce that current. However, Lord Kelvin failed to achieve this, although the device was very interesting for its time, and today existing scales can be seen in some museums dedicated to technology and metrology.

Do you want to enjoy cheap electricity? It is worth paying attention to photovoltaics:

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