Identifying the gaps in students’ understanding of manometer reading

Abstract

Physics, widely regarded as a difficult subject, is also abstract in nature whereby most of its concepts are intangible and hard to imagine. For instance, the concept of pressure, although it is a difficult concept to learn, it is also an important topic to master. Pressure not only appears in physics but also in other scientific fields such as in chemistry as one of the physical changes in the rate of change of reactions, and in biology or medicine involving blood pressure. In this study, students’ understanding on the topic of pressure will be reported. Specifically, in identifying the students’ misconceptions on manometer reading. A manometer is an instrument that uses a U-tube containing a liquid (either mercury or water) to measure gas pressure. From the interviews conducted with eleven Year 9 students, two main misconceptions were identified. The first misconception was on the existence of air pressure. The students failed to recognise its presence, as the effects of air pressure are often not obvious and undetectable. Additionally, two students on two separate interview occasions had referred to air pressure as vacuum. Another misconception was mistakenly taking the high liquid level of a manometer column as high pressure acting on that side and vice versa. This misconception is caused by again failing to comprehend that air and also gas pressure can cause liquid levels to change. Identifying these misconceptions will indeed assist Physics secondary school teachers to confront the issues relating to the difficulty concerning the pressure concept.