The apparatus use an accuracy of 10-5 Newton's force sensor in experiment, controlled electricity are brought in live ball situation, the electrostatic interaction force can be read out directly from panel, very easy and safe to show Coulomb's Law. The students can make the experiment safely and finally draw the curve correctly.

Attention:
--Working Condition: Working Temperature：≤26℃，Relative humidity：≤50%
--High Precision may influenced by even small wind flow. Please use protect cover to prevent air flow influence.
--Will take about 10 seconds to self-test when powered on.

Coulomb's law
The scalar form of Coulomb's law is an expression for the magnitude and sign of the electrostatic force between two idealized point charges, small in size compared to their separation. This force (F) acting simultaneously on point charges (q1) and (q2), is given by F＝K*Q1*Q2/R*R (Coulomb's Law).Where r is the separation distance and Ke is a proportionality constant. A positive force implies it is repulsive, while a negative force implies it is attractive.[7] The proportionality constant Ke, called the Coulomb constant (sometimes called the Coulomb force constant), is related to defined properties of space and can be calculated based on the speed of light to be exactly.