The concept of the scale of the universe has come up multiple times with my kids, and our friends, so I thought I’d put together a few links and resources we’ve used.
There is the ‘classic’ video (film-strip style) from the Eames Office, Powers of Ten and now with its accompanying website.
There is the superb flash animation: Scale of the Universe 2 by Cary Huang and Michael Huang (the (at the time) 14-year-old htwins). [Hmmm… embedding it doesn’t work, sorry]
There is The Known Universe by American Museum of Natural History, which you can interact with via their Digital Universe 3D Atlas software (powered by Partiview) and presented by one of the makers at TED (Carter Emmart).
If you want to just think about really big numbers too, check out Numberphile‘s video of Googols and Googolplexs.
I Am Chris Nolan.ca 
Khan Academy now has a section on Scale of the Universe (https://www.khanacademy.org/science/cosmology-and-astronomy/universe-scale-topic) too. I haven’t reviewed it yet, but wanted to add it.
An introductory picture book on the topic is BIG AND SMALL, ROOM FOR ALL (https://www.goodreads.com/book/show/6415631-big-and-small-room-for-all).
These are great resources and inspiration for many generations. You may also like the Cozmic Zoom application which is a kind of interactive Powers of Ten.