Why does electrostatic force move water but not magnetism?

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Discussion Overview

The discussion explores the differences between electrostatic and magnetic forces, particularly in their effects on water. Participants examine why electrostatic forces can influence water significantly while magnetic forces do not appear to have the same effect.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant notes that a plastic shopping bag can push and pull tap water due to electrostatic forces, while a magnet does not affect the water.
  • Another participant mentions that water is slightly diamagnetic, indicating it is repelled by a magnetic field.
  • A third participant suggests that the magnetic field of a magnet is insufficient to produce noticeable effects on water due to its small magnetic dipole moment, contrasting this with the electric dipole moment of water, which can be affected by moderate electrostatic fields.
  • The concept of electric dipole moment is introduced as a measure of the separation of positive and negative charges in water, while the magnetic moment is described in terms of its influence in external magnetic fields.

Areas of Agreement / Disagreement

Participants present multiple viewpoints regarding the effects of electrostatic and magnetic forces on water, with no consensus reached on the overall comparison of these forces.

Contextual Notes

Some assumptions about the strength of magnetic fields and their effects on water molecules remain unresolved, as well as the specific conditions under which these forces operate.

Who May Find This Useful

Readers interested in the interactions between electromagnetic forces and materials, particularly in the context of water and its properties.

student34
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So I was surprised to notice that my plastic shopping bag was able to actually push and pull tap water significantly far with its electrostatic force. But when I put a magnet near the water nothing happened. What makes the electrostatic force so different from magnetic force; isn't it just two kinds of the same force (electromagnetic force)?

I know the basics about the properties of water (atomic structure, polarity, intermolecular forces [such as hydrogen bonding] that cause adhesiveness and cohesiveness in the water, etc) and electrostatic force (and electromagnetic force which is perpendicular to moving charges).

None of my basic knowledge even comes close to explain what pushes and pulls the water and why that doesn't happen with magnetism.
 
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Water is slightly diamagnetic, meaning it is repelled by a magnetic field.
 
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In short the magnetic field of the magnet is not big enough to produce any noticeable effect. This is because the water molecules have a small magnetic dipole moment therefore they need a big magnetic field to affect em. On the other hand the water molecules have not so small electric dipole moment so a moderate electrostatic field can have small but noticeable effect on them.

The electric dipole moment is a measure of the separation of positive and negative electrical charges in a system of electric charges, that is, a measure of the charge system's overall polarity

The magnetic moment of a magnet is a quantity that determines the torque it will experience in an external magnetic field. A loop of electric current, a bar magnet, an electron(revolving around nucleus), a molecule, and a planet all have magnetic moments.
 
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Thanks everyone, it makes sense now.
 
student34 said:
why that doesn't happen with magnetism.

Watch at 0:57

 
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