By measuring the mass and volume, the density is calculated according to the formula ρ=mV;

(2) According to the number 1, the scale value is 0.2g, so its reading is 20g+20g+3g=43g.

(3) As shown in Figure 2, the graduated value of the measuring cylinder is 2ml, so its reading is 30ml = 30cm 3；;

Then the mass of oil m=43g- 16g=27g.

ρ= mV = 27g 30 cm3 = 0.9g/cm3 = 0.9× 103kg/m3

When all the oil in the beaker is poured into the measuring cylinder, it cannot be completely emptied, so the volume measurement is small and the density measured according to the density formula is large.

So the answer is: ρ = mv;

Mass of empty beaker

m0/g？ Total mass of beaker and oil m 1/g? Volume of oil

V/cm3？ Density of oil

ρ/kg.m3 16？ 43? 30? 0.9× 103 evaluation: too large.