Electroscope

What is an Electroscope?

An electroscope is a scientific instrument to detect a presence of an electric charge, and / or a type of an electric charge.

Neutral Electroscope

An electroscope can be Neutral, Positive, or Negative. This part explains about a netural electroscope. If an object is brought closer to the ball:

1. If the object is neutral, nothing will happen.
2.  
   

   If the object is positively charged, the electrons will move upwards (attracted by the object) to the ball, and the protons will move downwards (repelled by the object) to the golden leaves.
   These will result in the protons repel each other that the golden leaves to seperate further. (see image)

3.  
   

   If the object is negatively charged, the protons will move upwards (attracted by the object) to the ball, and the electrons will move downwards (repelled by the object) to the golden leaves.
   These will result in the electrons repel each other that the golden leaves to seperate further. (see image)

An important point to mention is that a neutral electroscope cannot be used to differ between a positively charged and a negatively charged object, because in the real world, the behaviour of the golden leaves will be identical to each other.

Positive Electroscope

Another type of elecroscope is a positively charged electroscope. This means that the protons of the electroscope has been seperated by the electrons with conduction. If an object has been brought closer to the ball of the electroscope:

1.  
   

   If the object is positively charged, more protons will move downwards (repelled by the object) to the golden leaves.
   These will result in the protons repel each other that the golden leaves to seperate further. (see image)

2.  
   

   If the object is negatively charged, more protons will move upwards (attracted by the object) to the ball.
   These will result in less protons in the leaves that the golden leaves will become closer to each other. (see image)

Negative Electroscope

If an object has been brought closer to the ball of the negative electroscope:

1.  
   

   If the object is positively charged, more electrons will move upwards (attracted by the object) to the ball.
   These will result in less electrons in the leaves that the golden leaves will become closer to each other. (see image)

2.  
   

   If the object is negatively charged, more electrons in the ball will move downwards (repelled by the object) to the golden leaves.
   These will result in the electrons repel each other that the golden leaves to seperate further. (see image)

Electric Field

An electrtic field is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. ^[1]

Behaviours of Positive and Negative Charges

A proton has a radially outward electric field from the proton's position, while an electron has a radially inward electric field from its position.

Examples

References

1. Browne, p 225: "... around every charge there is an aura that fills all space. This aura is the electric field due to the charge. The electric field is a vector field... and has a magnitude and direction."