The purposes of the research were as follows: 1) To evaluate the efficiency of the online lessons on finding information on the Internet using demonstration method for Grade 5 students at Tessaban 5 Watprapathomchedi School, 2) To compare the students’ learning achievement before and after learning with developed online lessons, and 3) To the students’ satisfaction towards learning with the developed online lessons using demonstration method. The sample group used in this research were 25 Grade 5 students at Tessaban 5 Watprapathomchedi School. The tools used in this research were the management plans the online lessons, the academic achievement questionnaires, and the satisfactionnaires. The statistics used in data analysis, were percentage, mean, standard deviation and t-test dependent.

The research findings showed that :  1) The efficiency of the learning management of Science Department on finding information on the Internet for Grade 5 students at Tessaban 5 Watprapathomchedi School was at the level of 80.80/79.90 , 2) the students’ learning achievement after learning with the online lessons was statistically singnificantly higher than before learning at the level of .05 , and 3) the overall students’ satisfaction towards learning with the online lessons using demonstration method was at a high level.