1. The problem statement, all variables and given/known data The individual threads in a cloth are very close together. Design an experiment to investigate how the rate at which water passes through the material depends on the separation of the individual threads in the material. Available equipment: Ammeter,battery,cloths,wires,funnel,large tank of water,low power laser,measuring cylinder,metre rule,oscilloscope,screen,top pan balance,umbrella,voltmeter 2. Relevant equations Null 3. The attempt at a solution So I know how to measure the distance between the cloth via diffraction, with the laser light using the interference patterns. What I actually want to know is how the ammeter,voltmeter and oscilloscope actually fit into this. Best I could think of is that they are used to regulate the power flowing into the laser to keep it constant? Also in measuring the water, why would you need a top pan balance if you can measure the water with a measuring cylinder? So wouldn't the weight of the water be irrelevant?