Hi @KathrynM114,
Talk to your colleagues and school district about new course materials that don't require Flash Player. Everyone had 3-1/2 years advance notice that Flash Player was ending on Dec 31st. There is no replacement for Flash Player.
July 2017 Announcement
https://theblog.adobe.com/adobe-flash-update/
Flash Player EOL
https://www.adobe.com/products/flashplayer/end-of-life.html
Most interactive content can be created with HTML, JavaScript, CSS, WebGL, SVG and other native web technologies by people who know how to do it. However this is entirely out of your hands.
Contact the museums and ask them when they plan to rebuild their site. Sadly, they may not even know there is a problem. For the rest, I think it's fair to say that if they haven't updated their sites by now, they probably never will and won't be around much longer.
Keep up the good work. The world needs more art teachers!! 🙂