Question

The apparatus shown in the following diagram is Garreau’s potometer designed to demonstrate unequal transpiration from the two surfaces of a dorsiventral leaf. Before keeping the leaf in between the cups, anhydrous calcium chloride (CaCl₂) contained in two small vials were weighed and placed in both the cups. The ends of the cups were closed with corks through which two mercury manometers were connected. After few hours, CaCl₂  vials were taken out and weighed again.

What is the purpose of using a manometer?

Answer 1

Manometer is used to measure the pressure. In order to measure the pressure exerted by the fluid, the fluid is allowed to exert pressure on one of the closed ends of the tube. Under the effect of the pressure, the liquid inside the manometer tube gets displaced and the amount of displaced liquid is measured.