Naphthalene balls vanish in a few days because of evaporation when left in the open.
Naphthalene balls become smaller gradually when kept out in the open for a few days.
Naphthalene balls become smaller in size when kept exposed for a few days. This is because of sublimation.
Naphthalene balls get smaller in size when kept exposed to air for a few days. This happens because of sublimation.
Naphthalene balls become smaller in size when kept exposed to air for a few days.