Why does a beach ball weigh less than a bowling ball?

The beach ball pushes harder against Earth.

The beach ball has more air.

The beach ball has more mass.

The beach ball is less strongly attracted to Earth.

The main reason a beach ball weighs less than a bowling ball is that the beach ball has less mass. Mass is a measure of the amount of matter in an object, so the beach ball, which is mostly filled with air, has much less mass than the solid bowling ball. This difference in mass is what causes the beach ball to weigh less when compared to the bowling ball.