We've been using Apologia's Young Explorer series for science all along. I know most of us are eager to dive into the lessons with their eye-catching illustrations and conversation-style text, but have you ever gone back to read the introduction? Each book has the website and password to access additional files and information specifically for that text. This is where I got the idea for our paperclip model of the solar system. In order to visualize the distance between the sun and planets we had to count out paper clips and line them up down the hall.
From the wall we have Mercury, Venus, Earth and Mars-- a total of 15 paperclip distance.
Then we started counting hundreds and hundreds of paperclips. We used the 1 inch clips and we still ran out of room in our hallway--we had to turn a corner and keep going for Pluto (which is still a planet in my book).