The weight could be different, metals have a higher mass than nonmetals, so when occupying the same amount of space, the weight of the metal is far more.
"Electrostatic forces are attractive or repulsive forces between particles that are caused by their electric charges."
Echo sounding is a type of SONAR used to determine the depth of water by transmitting sound pulses into water. The time interval between emission and return of a pulse is recorded, which is used to determine the depth of water along with the speed of sound in water at the time.
