Public schools are required by law to have a filtering program in place. This software blocks students from looking up certain words. They often restrict students from searching certain sites (like Facebook) or from using email. Luhrs Elementary, on campus, is required to use filtering software. See Wikipedia's article on content-control software for a general overview of this topic.
For lessson plans on specific topics, simply try Googling lesson plans and the topic. Below is a list of lesson plans I found when I Googled: Civil War lessons plans.