A super difficult physics question, I hope everyone can answer it directly, thank you! !

Super simple! Put two small stones into this half glass of water and the water level will rise. Measure the rising height with a scale and multiply it by the area of the cup bottom (calculated by the radius of the scale). After you get the volume, multiply it by the density of water to get the quality of the stone! Finally, divide the mass by the volume to get it!