[题目]有一形状不规则的石蜡块,现要测定它的密度,但身边没有天平,也没有量筒,只有两个可以放进石蜡块的杯子和一根自行车胎气门用的细长橡皮管,还有一桶水和一根大头针.请你设计一个实验来测出这块石蜡的密度(要求写出实验的原理和主要步骤,并导出计算石蜡密度的公式). [原解]a.将一个杯子装满水,放入石蜡块,溢出的水用另一空杯子接收. b.用橡皮管把接收到的水一滴一滴抽出来并记录下水滴数n. [Subject] There is a paraffin block of irregular shape, and its density is to be measured. However, there is no balance or a graduated cylinder. There are only two cups that can be put into a paraffin block and an elongated rubber tube for a bicycle tire valve. There is also a bucket of water and a pin. Please design an experiment to measure the density of this paraffin (requirements to write the principle of the experiment and the main steps, and derive the formula to calculate the density of paraffin). [The original solution] a. Fill the cup with water and place it in a paraffin block. The overflowing water is received in another empty cup. b. Use a rubber hose to take out the received water one by one and record the number of drops.