Solution

In the experimental arrangement in the picture above a polystyrene ball is used instead of a wooden chunk because polystyrene has an even greater volume than wood at equal mass. After the glass globe has been put onto it, the vacuum pump is switched on (on the right). If there is no (or little) air in the glass globe, there is not any effect of buoyancy anymore. Now you see that the polystyrene ball has got the greater mass.