Wanting to teach astronomy

I’m a Teaching Assistant and my students have expressed wanting to learn astronomy- during our last free period I was showing them what binary star systems are and roughly how they work. My question for you guys is what other astronomy lesson plans can I make for these guys for our summer school curriculum? And what places can I go to for say work sheets for these kids aged 13-14? If anyone has questions I’m almost always on my phone and respond relatively quickly