npsm 새물리 New Physics : Sae Mulli

pISSN 0374-4914 eISSN 2289-0041


Research Paper

New Physics: Sae Mulli 2007; 54: 519-525

Published online June 30, 2007

Copyright © New Physics: Sae Mulli.

New Operational De?nition of Mass for 7th-grade Science Class

Jaewoo KIM1,* Wonkun OH2

1Munchang Middle School, Seoul 156-848
2School of Science Education, Chungbuk National University, Cheongju 361-763



Most current 7th-grade science textbooks explain that spring scales can be used for measuring weight only, not mass. However, spring scales can also be used to measure the gravitational mass of a body. Moreover, a simple spring oscillator can be used to measure the inertial mass in a weightless situation. Here, we suggest that such a measurement can give an alternative way of operationally de?ning ‘mass’ We took 123 students of 7th grade as subjects. They were made to measure the mass by using spring scales and spring oscillators. From the analysis of their performances, we were able to conclude that the new operational de?nitions of mass have enough reliability and accuracy for young students. These new de?nitions can help overcome the logical de?ciency of textbooks' explanations and help students understand the concept of inertial mass.

Keywords: Textbook, Concept of mass and weight, Gravitational mass, Inertial mass