This article reports on research into learning gains made by children aged 10-12 when they studied astronomy using learning activities in a constructivist environment consolidated by access through the Internet to a scientific-grade telescope. Young people often hold naive or alternative ideas about scientific phenomena from early childhood. Since these ideas may be believed well into adulthood in spite of attempts to dislodge them, educators must address the problem actively from grade school onward. In the program reported in the article, a learning environment supported by peer interaction and access to exciting and credible Internet resources has lead to the discard of naive ideas and acceptance of explanations based on scientific findings. (Contains 4 figures.)