How does the relationship between pressure and volume in a gas system demonstrate that they are directly proportional?

In a gas system, pressure and volume are directly proportional, meaning that as pressure increases, volume decreases, and vice versa. This relationship is known as Boyle's Law, which states that at a constant temperature, the pressure of a gas is inversely related to its volume. This can be demonstrated by conducting experiments where pressure and volume are measured and compared, showing a consistent pattern of change in one variable corresponding to changes in the other.