对密度知识的考查往往伴随着对天平和量筒的考查。下面结合天平和量筒使用的顺口溜,给同学们进行总结:一、托盘天平使用一放平,二归零,三调螺母梁平衡。螺母要向轻端移,天平调好不要动。左物右砝两盘盛,加减砝游再平衡。取码需用镊子夹,先大后小记心间。砝游之和是读数。如若物砝位置反,读数砝游要相减。 The examination of density knowledge is often accompanied by examination of scales and graduated cylinders. The following combination of balance and graduated cylinder use jingles, to the students to summarize: First, the use of a flat tray balance, two zero, three adjustable nut beam balance. Nut to the light end of the shift, balance do not move well. Left and right weight two sets of Sheng, plus and minus weight and then rebalance. Need to take code tweezers folder, after the first small mind. Weight and the sum of readings. If the weight is reversed, the readings must be subtracted.