The two physical quantities you need to measure to determine the density of a liquid are:

1. Mass: This is the amount of matter in the liquid. It is typically measured in grams (g).

2. Volume: This is the amount of space the liquid occupies. It is typically measured in milliliters (mL) or cubic centimeters (cm³).

Once you have these two measurements, you can calculate the density using the formula:

Density = Mass / Volume