This site provides lesson plans, interactives, and videos for grades Kindergarten through college. There are simulations to demonstrate many topics in all subjects. You can search the site by resource, grade level or subject.
Make their own books online. To view online is free. If you want to print it out there is a $5 fee. For younger children they recommend using one e-mail to create an account and use it on multiple devices. They have characters and objects students can add to their books. You can also upload your own images to go along with the stories.