Schoolphysics is an online resource base for all 11 to 19 year old Physics and Science students and their teachers. Resources cover 'Physics in Depth', 'Physics at a glance', animations, exam specifications, data, diagrams, photographic images and more.
Grade Level Grades 6-12
The 'web' link will take you to a website which includes teacher information, an experiment, and individual student practice. The information is not limited to gases. It also includes molecular movement in solids and liquids. Very appropriate for middle school.