Which flowmeter operates by sensing changes in the pressure differential created by fluid flow?

The correct choice is the differential flowmeter because it specifically measures the changes in pressure differential created by the movement of fluid through a system. In essence, this type of flowmeter relies on Bernoulli's principle, where the flow speed increases as the fluid passes through a restriction, leading to a drop in pressure. By measuring this pressure difference at various points within the flow path, the differential flowmeter can accurately calculate the flow rate.

Differential flowmeters are commonly used in various applications due to their reliability in measuring flow rates across different conditions and their capability to handle a wide variety of fluid types. They can provide precise readings even in environments where other types of flowmeters might struggle due to factors such as viscosity and temperature changes.

In comparison, paddlewheel flowmeters function by using a spinning paddle to measure flow, which is more mechanical and does not rely on pressure differentials. Spring probes often rely on displacement rather than pressure differences, making them unsuitable for this type of measurement. Electromagnetic flowmeters operate based on Faraday's law of electromagnetic induction, detecting flow changes through induced electrical signals rather than pressure differentials. Thus, the differential flowmeter stands out as the most appropriate choice for sensing changes in pressure differential.