When you bring a balloon that has been charged (usually by rubbing it on your hair or a cloth) near a wall, something interesting happens at the molecular level. The balloon typically acquires a negative charge due to the transfer of electrons.
As you bring the negatively charged balloon close to the wall, the negative charges in the wall (which are generally stationary electrons embedded in the material) are repelled due to like charges repelling each other. This causes a slight shift in the distribution of charges within the wall. The negative charges (electrons) are pushed away (or move back into the wall), leaving behind a region of positive charge closer to the balloon.
This creates an attractive force between the negatively charged balloon and the positively charged area of the wall. The attraction is strong enough to make the balloon stick to the wall. This phenomenon is known as electrostatic induction.
In summary, when the balloon approaches the wall, the nearby negative charges in the wall are repelled, leaving a region of positive charge that attracts the balloon, resulting in it sticking to the wall.
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