The most influential activity we did during our Solar System studies, was to make a solar system model on our school room wall. I used this website to make it as much as we could to scale - while we couldn't put them to scale as far as distance goes - it was really eye opening to see the size scale.
This really helped the kids to grasp how much bigger the sun is than the earth (I mean as much as our human minds really can) and this lead to some awesome discussions on how much bigger and powerful God is who created the sun.
The kids helped paint our 48 inch sun, and Treyton and I colored the planets with colored pencils. To give you a sense of the sizes, mars was the size of a hole punch (and it's too big to be accurate!) and earth was less than 1/2 an inch (.4 actually).
Both of the older kids colored a Solar System page showing the asteroid belt and the planets.
Treyton made a sun page to include in his science notebook - I cut out the sun for him, he glued it on. :)
He wrote 4 facts that he learned about the sun that he wanted to remember.
Alexa did a worksheet for her notebook (from Homeschool Creations, I think) seperating planets from things that were not planets.
I found this idea on pinterest to show the relationship between the sun, earth and moons orbits - obviously it's not anywhere near to scale, but that wasn't the big lesson on this one. This really helped Treyton to grasp the concept of the eclipses, and the difference between rotating and revolving. (Which reminds me, for Alexa, it helped her to spin and walk in a circle to understand rotating and revolving ---- fun times, but too much of it may be dangerous for your health :))
We are thoroughly enjoying Our Universe by Answers in Genesis. We are currently going through the planets and the kids are loving it!!