How can an object be charged by contact?

(N/A) When we touch a neutral object (such as a pith ball) with a charged object (such as an electrified plastic rod),some of the charge from the charged object is transferred to the neutral object.
As a result,the neutral object acquires the same type of charge as the original charged object.
This process is known as charging by contact or conduction.
For example,if a negatively charged plastic rod touches a pith ball,electrons flow from the rod to the ball,making the ball negatively charged.
Consequently,the pith ball is repelled by the plastic rod due to like charges,but it would be attracted to a glass rod that carries an opposite (positive) charge.