[alancalverd]

The voltmeter is on during the whole length of the experiment, including the zeroing event.
Different content of the buckets result in different voltage reading.
Different current through the liquids result in different voltage reading.

So you have disproved Ohm's law. Amazing.

Or maybe your diagram was wrong. Probable.

Don't be discouraged. A former colleague, loaded with every degree and accolade known to science, was astonished to discover that the fabulous apparatus he had invented produced no results at all. I was dispatched to "sort out those buggers in the workshop" and found that they had built exactly what he had drawn, including a carefully welded short  circuit exactly where he apparently wanted it. We replaced the weld with a Perspex insulator and restored the laws of physics before anyone noticed they were missing.

[hamdani yusuf (OP)]

So you have disproved Ohm's law. Amazing.

Not really. It's more likely that your understanding of the law is incomplete.

Ohm's law is an empirical relation which accurately describes the conductivity of the vast majority of electrically conductive materials over many orders of magnitude of current. However some materials do not obey Ohm's law; these are called non-ohmic.
https://en.m.wikipedia.org/wiki/Ohm%27s_law

The resistance of the voltmeter is quite high, with input impedance is 10~100 M Ohm, according to the data sheet. It can measure voltage without drawing much current.

This video might open your mind.

Or this one.

I also see a voltmeter connected between the stands?

This is partially inspired by electrostatic induction in electroscope.

But instead of detecting electrostatic force, my experiment was designed to measure the small difference in electrodynamic forces between two ionic currents.

In these situations, Ohm's law isn't very helpful, since the resistance is not constant, or measuring it reliably isn't practical.

[hamdani yusuf (OP)]

Electrodynamic Balance 1: Preparation

Now we will show the preparation for electrodynamic balance experiment. This video is intended to help anyone who wants to replicate the experiment to make sure its repeatability. I found that merging this with the experiment itself will produce a huge video which is harder for me to handle.

The size of white square made of corrugated plastic board is around 25 cm wide. So you should be able to estimate the size of the other components.

[hamdani yusuf (OP)]

Or maybe your diagram was wrong. Probable.

There are two components I didn't include in the drawing, which are re-zeroing switch and the step down transformer. It's for simplicity, because in principle, the experiment can run without them. Their purpose is for practicality.

[Bored chemist]

if so, I'd like proper specifications, sizes currents, concentrations etc so you can't say I didn't do it right.

Now I'm done recording the experiment using 3 types of chloride salts, ie NaCl, KCl, and MgCl2. It will take some time to edit, add narrative and illustration, and then upload it to my YouTube channel. So please be patient, since I'm having a tight schedule in my work place. So little time so much to do.

Her are some observations during the experiment.
Even with the same solutions in both containers, and no electric current flowing through them, some voltage was shown. It disappeared when the cans were connected, but reappeared after they were disconnected.
Difference in volume of the liquids affects the voltage readings, even with no current.
Electrostatic charge build up on the liquids affects the voltage readings. It can occur when the liquid is poured into the container, or other handling related to triboelectricity.

To minimize variance, the solutions used in the experiment were set to have conductivity around 19 mS/cm, because the portable conductivity meter I used can't show any value above 20 mS/cm.

If you are too lazy to read the description two pages before, I don't really think you are diligent enough to carry out the experiment.

Show me where  you mentioned the concentrations or stop being a dick and tell me what they are.

[hamdani yusuf (OP)]

My experiment can be seen as an extension  from The moving magnet and conductor problem. It concerned with the situation where there are more than one magnet relatively moving from one another. How should their influence on the conductor (or a test particle) be combined?
What if the magnets are replaced by moving ions?

The moving magnet and conductor problem is a famous thought experiment, originating in the 19th century, concerning the intersection of classical electromagnetism and special relativity. In it, the current in a conductor moving with constant velocity, v, with respect to a magnet is calculated in the frame of reference of the magnet and in the frame of reference of the conductor. The observable quantity in the experiment, the current, is the same in either case, in accordance with the basic principle of relativity, which states: "Only relative motion is observable; there is no absolute standard of rest".[1][better source needed] However, according to Maxwell's equations, the charges in the conductor experience a magnetic force in the frame of the magnet and an electric force in the frame of the conductor. The same phenomenon would seem to have two different descriptions depending on the frame of reference of the observer.
https://en.m.wikipedia.org/wiki/Moving_magnet_and_conductor_problem

[hamdani yusuf (OP)]

Show me where  you mentioned the concentrations or stop being a dick and tell me what they are.

In most practical applications, conductivity of the solution is a good indicator of its concentration, especially when there's only one type of dissolved chemical substance. I thought you already knew that. I'm sorry if I was mistaken.

[Bored chemist]

In most practical applications, conductivity of the solution is a good indicator of its concentration

No. It is not. It is strongly temperature dependent.
Obviously, if the conductivity was a useful proxy I wouldn't have needed to ask.


 I thought you already knew that. I'm sorry if I was mistaken.

Answer the damned question.

What concentration of these salts did you use?

Do you not actually know?

[hamdani yusuf (OP)]

In most practical applications, conductivity of the solution is a good indicator of its concentration

No. It is not. It is strongly temperature dependent.
Obviously, if the conductivity was a useful proxy I wouldn't have needed to ask.


 I thought you already knew that. I'm sorry if I was mistaken.

Answer the damned question.

What concentration of these salts did you use?

Do you not actually know?

Overthinking is a common problem among us which prevents from doing new things.
If you watched my preparation video  to minute 2:30, you can read yourself that the temperature is around 27 deg C.
I didn't measure the concentration in percentage because I prioritize the consistency in the electrical current through the different types of solutions. It should be obvious that for this purpose, conductivity is the correct parameter to be measured.
Is there anything else you need to know before starting your experiment?

[hamdani yusuf (OP)]

My point is, we've gotten used to the concepts of electric and magnetic fields to describe interactions among electrically charged particles while ignoring their masses.

And when mass is important, we include it. How else can I operate a linear accelerator? Or teach classic experiments to determine e/m and the mass of an electron? 

The mass of the source of magnetic field doesn't show anywhere in Lorentz force formula.

Here it is.

This video provide theoretical background for designing an electrodynamic balance, intended to study the origin of magnetic force, and its relationship with electricity and gravity.

So far, I haven't found any objection to the theoretical background that I described in the video. It should naturally lead to the conclusions that led me to design the electrodynamic balance experiment. Perhaps someone with different perspective can find out what I have missed.

My experiment can be seen as an extension  from The moving magnet and conductor problem. It concerned with the situation where there are more than one magnet relatively moving from one another. How should their influence on the conductor (or a test particle) be combined?
What if the magnets are replaced by moving ions?

At least initially, the goal of this experiment was to demonstrate that different ionic current can produce different electrodynamic forces which can be measured by a sensitive Voltmeter. Other differences in parameters are controlled and minimized, leaving the mass to charge ratio of the current carrying ions as the most obvious and intentional difference.

[Bored chemist]

Is there anything else you need to know before starting your experiment?

Are the cans on which you balance things important?
Are  they tinplate (which is ferromagnetic) or aluminium (which is diamagnetic)?

Re "I didn't measure the concentration in percentage because I prioritize the consistency in the electrical current through the different types of solutions. It should be obvious that for this purpose, conductivity is the correct parameter to be measured."
Were you not expecting anyone to try to repeat it?
How many people have a means to measure mass and how many have the means to measure conductivity?

If I were to use solutions of copper chloride and copper sulphate would you expect to find an effect? What about the acetate?
Would it affect the magnitude of the hypothesised voltage?
The reason I ask is that, if I used copper electrodes and suitable copper salts, the reactions would all be reversible so you wouldn't need to worry about polarisation effects.

How does the predicted effect vary with the scale of the equipment?

Overthinking is a common problem among us which prevents from doing new things.

Thinking is a thing that prevents us doing pointless things.

We call it planning.

[hamdani yusuf (OP)]

Are the cans on which you balance things important?
Are  they tinplate (which is ferromagnetic) or aluminium (which is diamagnetic)?

I tried both, and the results are the same.

[hamdani yusuf (OP)]

Re "I didn't measure the concentration in percentage because I prioritize the consistency in the electrical current through the different types of solutions. It should be obvious that for this purpose, conductivity is the correct parameter to be measured."
Were you not expecting anyone to try to repeat it?
How many people have a means to measure mass and how many have the means to measure conductivity?

You can measure conductivity using DIY tools. I think school kids are familiar with this kind of things. I don't want to spoon feed everyone like toddlers. I respect their intelligence.

[hamdani yusuf (OP)]

If I were to use solutions of copper chloride and copper sulphate would you expect to find an effect? What about the acetate?
Would it affect the magnitude of the hypothesised voltage?
The reason I ask is that, if I used copper electrodes and suitable copper salts, the reactions would all be reversible so you wouldn't need to worry about polarisation effects.

Yes. I expect that ionic mass is one factor affecting the electrodynamic forces in the conductors nearby.
But for larger molecules, other effects like molecular rotation may generate displacement current which affects the measurements.
That's why I stick with monoatomic ions. I used sodium sulphate and sodium chloride in the preliminary study simply because they were already available for me without purchasing.

[Bored chemist]

You can measure conductivity using DIY tools.

Not if you want the right answer.

[hamdani yusuf (OP)]

How does the predicted effect vary with the scale of the equipment?

Increasing the current generally increases the measured voltage.
Increasing the size of the equipment increases the number of affecting ions, but also the average distance between them and the conductor below. But in principle, it can be calculated by integration.

[Bored chemist]

That's why I stick with monoatomic ions. I used sodium sulphate and sodium chloride

Can you tell me more about this monatomic sulphate ion?

[hamdani yusuf (OP)]

You can measure conductivity using DIY tools.

Not if you want the right answer.

Then buy or borrow a conductivity meter. It's not an expensive tool.

[Bored chemist]

Also, when I see the beakers balanced on top of the tins it looks dangerously top-heavy to me.

Are the bits marked in green vital?
Could you just use a couple of metal plates?

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[Bored chemist]

You can measure conductivity using DIY tools.

Not if you want the right answer.

Then buy or borrow a conductivity meter. It's not an expensive tool.

I have one (and  a decent one isn't cheap).

You talk about "

I don't want to spoon feed everyone like toddlers.

Have you even seen a real scientific paper- the sort where they tell you what supplier they used for the chemicals?