This is a site run by the UIUC Department of Physics and their outreach program The Physics Van. Although this is focused more towards the elementary level, it is still a good source for Q and A about physics topics.
This web page is from the UIUC Physics Van and it is a place where people can ask questions about things in their everyday life and get answers from people who are knowledgeable in related scientific fields.
This page gives links to many resources which could be used to enrich physics instruction at the secondary level. Some examples of the resources are an examination of the physics of race cars, roller coasters, and links to some simulations.
This page lists some misconceptions which have been taken from college Physics students' essays and exams. It could be a good tool to show students that even college physics students have basic misconceptions and use this to emphasize the importance of knowing the basics very well.
This resource I found through Google search helps students understand different physics phenomena. These simulations show the students the physics behind various topics such as forces and motion.
This is another site full of good physics simulations which could be used to help students explore different topics in physics. These simulations may explore topics which are too complicated for students to directly explore in classroom experiments, or topics which are typically confusing for students.
This is about the history of chemistry, and specifically talks about the life and finding of Max Planck. Any Chemistry or Physics teacher trying to make quantum mechanics more relevant to students will find this useful.
This page goes through an explanation of the physics of many common rides at amusement parks. It could be used to gain the interest of students to new topics to be presented in class.
This website has a lot of fun easy science experiments. I found this website because my cooperating teacher uses it in her study hall classroom. The experiments relate to many different types of science. Most of them require minimal materials!
This website provides a great number of really interesting articles about biology that could easily be incorporated into the classroom and inspire students to investigate further.
I found this site when looking for ideas to use in an upcoming demo/lesson about chemical and physical properties/changes. I guess there are only 25 experiments listed currently, but it gave me some good ideas to potentially use!