If the pressure on a gas is increased, then its volume will decrease because the gas molecules will be pushed closer together. Did the data support the hypothesis (above)? Justify your answer. Sample Justification: As weight was added to the top of a syringe, the volume of the air trapped in the syringe decreased. The weight and the surface area of the plunger were used to calculate pressure. As more weight was added, the pressure increased. The volume decreased in response. Did you mention that adding weight increased the pressure? Did you mention that volume decreased as the pressure increased?