The porosity of sponges was measured by the solvent method. The solvent was chosen as ethanol because of the insolubility of sponges in ethanol. A certain volume of the sponge

was cut accurately. The sample was dipped into ethanol and removed after saturation. The mass of the sample was measured before and after immersion in ethanol. The swelling degree (P) was calculated by the following formula

P=(m2-m1/vXp)X100

where m1 and m2 represent the weight of the sample before and after

immersion in ethanol, respectively. V and ρ represent the sample

volume and the density of ethanol (0.785 g/cm3).

I would like to ask if sample volume V is the volume of ethanol we take to immerse the sponge into it? Can somebody please clear my doubt?

Thank you.