New Perspectives in Science Education

This paper presents the soil pH measuring development which is essential practice for primary high school student in environment science subject or applied to agricultural area, this trial useful for rural areas which are deficient laboratory equipments. The experiment designed by Completely Randomized Design (CRD), compared with 3 soil series, Haplorthoxs, Haplustalfs and Dystropepts soil series, from Tha-Mai, Kamphaeng-Saen and Yang Talat districts, Thailand, controlled treatment with difference the soil : water ratio and pH measuring, made a comparison between pH meter and pH paper. The result appeared the soil : water ratio which were 1:5, 1:10 in beaker extraction technique and 1:10 in 30 ml screw cap plastic bottle technique that were not significant difference (p>0.05). However, pH paper cannot detected pH value with 1:1 soil : water composition. While, 30 ml screw cap plastic bottle separated method with 1:9 soil : water composition, compared with 3 Soil Series then, pH values analyzed by pH meter were 5.93, 6.37 and 5.37 ,as pH paper evaluated 6.0,  6.5  and 5.5 respectively.