 # Coulomb's law facts for kids

Kids Encyclopedia Facts

Coulomb's law is a function developed in the 1780s by physicist Charles-Augustin de Coulomb. It explains how strong the force will be between two electrostatic charges. Electrostatic means electric charges without any motion.

## Direction This picture shows how Coulomb's Force act; similar charges pushing against each other and opposite charges attract each other

Let's think of two electric charges existing in an empty space. If the two charges are opposite, (+) and (-) charges for example, they will attract each other. And if two charges are both the same, both (+) or both (-) for example, they will push each other. This is similar to how magnets act, as N and S attract each other, and as N and N, S and S push each other.

This is because electric charges make an electric field. If two fields exist in the same space at the same time, then the two fields exert (~ put) force on each other. The force they make on each other is called 'Coulomb's force' or the electrostatic force. Coulomb's law explains how big the force will be.

## Scale

Coulomb's law explains the scale between two electric charges. The scale of electrostatic force follows the function below. $F = {K_c}\frac{q_1q_2}{r^2}$

Coulomb's law explains that the force scale F is relative to ratio of $q_1,q_2$, $\frac{1}{r^2}$. $q_1$ and $q_2$ are the scales of each electric charge. $r$ is the distance between the two electric charges. And $K_c$ has a certain value. It does not change relative to $q_1$, $q_2$ or $r$. While ${K_c}$ remains constant, when multiples of $q_1$ and $q_2$ become bigger, the electrostatic force will also get bigger. When the distance $r$ becomes bigger, the electrostatic force will become smaller by the ratio of $\frac{1}{r^2}$.
The exact size of $K_c$ is \begin{align} k_c &= 8.987\ 551\ 787\ \times 10^9 \\ \end{align} $\approx 9 \times 10^9$N m2 C−2 (or m F−1). This constant is called Coulomb's force constant or the electrostatic force constant.

## Inverse-square law

The relation between the force of pushing or pulling (F) and the distance between the particles ( $r$) follows the Inverse-square Law. Inverse-square law means that when the distance $r$ grows bigger, the force gets weaker by the ratio $\frac{1}{r^2}$. Gravitation, Electromagnetic radiation, and sound loudness also follow this law.

## Images for kids Coulomb's law Facts for Kids. Kiddle Encyclopedia.