A useful science webpage for junior high students, teachers, or simply enthusiasts is The Science Spot. The Science Spot offers classroom activities for 16 different fields of science. For example, chemistry, astronomy or ecology. These classroom activities are rather interesting. There is an activity for balancing chemical equations. The activity is called "Snowman Challenge Game" and students are asked to work in pairs to match equations using snowman cards. Everything for this activity is provided, even the snowman cards, free to print!
Another great feature of The Science Spot, is the "Science Starters". Simply, they are short PowerPoints created to "reinforce" the most important concepts of a topic.