酒精(指乙醇)在使用前常用玻璃酒精计测量其浓度,然后按标示值计算用量。通常只注意酒精的挥发性,而不注意温度的变化对酒精计标示值的影响。同一瓶酒精,在冬天(室温以5℃计)测得标示值为80%,而在夏天(室温以30℃计)测得标示值为87%,差异竟达7%。玻璃酒精计实际上是一个比重计,不过在标示的刻度上,以酒精浓度代替比重刻度而已。酒精计上标示的酒精浓度,是根据温度20℃时,各种浓度(V/V) Alcohol (referring to ethanol) before use, often with a glass alcohol meter to measure the concentration, and then calculated according to the marked amount. Usually only pay attention to the volatility of alcohol, without paying attention to the impact of temperature changes on the meter marked value. The same bottle of alcohol was 80% measured in winter (at room temperature at 5 ° C) and 87% in summer (at room temperature at 30 ° C) with a difference of 7%. Glass alcohol meter is actually a hydrometer, but in the marked scale, the alcohol concentration instead of specific gravity scale only. Alcohol on the mark of the alcohol concentration is based on the temperature 20 ℃, various concentrations (V / V)