Fourth Graders’ Understanding of the Volume of Water and Water Droplets in a Covered Container

Abstract

All 5 main publishers’ official science textbooks for 4th grade of elementary schools include experiments in which, after a few days, the volumes of water in a covered and an uncovered container, initially holding equal amounts, are compared. On the topic of “the water that goes out into the air”, or “evaporation”, we conducted an experiment on the conditions inside a covered container and its water volume in science lessons with 159 students in a public elementary school in Chiba city. We investigated what the students expected regarding the volume of water and their degree of understanding of the experiment’s results. The results revealed that, in the prediction stage, 119 pupils (74.8%) were able to think scientifically and considered that, inside the container, as the water evaporates and becomes droplets, the water level drops and its volume decreases. However, such students were not convinced of the experiment’s result demonstrating that the water volume did not decrease materially. Our results indicate that, in the future, although it is appropriate to think that the water volume decreases only by an amount corresponding to the water droplets attached to the surface of the container, it is necessary to consider that, as the volume of water droplets is very minute, the drop in water level is nearly imperceptible, so that the pupils who made predictions by thinking scientifically can be convinced.