Explain the construction of a barometer.

Question: Explain how a barometer is designed and how it measures atmospheric pressure. Answer: A barometer is designed based on the principle of balancing the weight of a liquid column against the atmospheric pressure. Its main components include an evacuated glass tube filled with mercury, a container with mercury, and a measurement scale. The tube is submerged in the container of mercury, and atmospheric pressure pushes the mercury in the container up the tube. The height of the mercury column inside the tube changes according to atmospheric pressure - higher pressure forces the mercury upwards, while lower pressure allows its weight to push it down. By measuring the height of the mercury column and utilizing the formula P = ρgh, where P is the atmospheric pressure, ρ is the density of mercury, g is the acceleration due to gravity, and h is the height of the liquid column, one can determine the atmospheric pressure.