Container for PP plastic ball in the water to test the density, but PP plastic ball will floating on the surface to be measured. The testing methods are optimized through experiments, through repeated comparison test, precision can be over 99%. The method is as follows:

1 with a special balance laboratory plastic PP ball weight, measure the actual quality of plastic PP ball is X.

2 with a certain amount of water poured into the measuring cylinder, measuring the water volume is Wl;

3 with a nylon string in a plastic ball and a ball hanging below the sink and the measured value C2;

4. From the water come up with plastic PP ball and iron, then just used iron alone sink into the water, measuring the data at this time is D3;

Two the density of the calculation formula to calculate the density of the 5 test data.

6 then the data minus second test the first test, the plastic ball density is PP.

Test method for density of hollow plastic balls