When a football is pumped, both volume and pressure of the gas inside it increase. Does this observation contradict Boyles’ law?
According to Boyles’ law, at constant temperature, the volume of a given mass of a gas is inversely proportional to its pressure. When the football is pumped, the quantity of air inside the football goes on increasing. As a result, the mass of air inside the football does not remain constant. Moreover, pumping causes rise in temperature of air inside the football. Thus, neither the temperature nor the mass of air remains constant. So, Boyles’ law is not applicable in this case.