Great ideas here! Just a quick added thought to expand, particularly on ZenScanner. Since you are teaching chem and physics at home, I imagine there will be lots of "why" and "how does" questions coming up throughout lessons. It might help to have a specific spot where you consistently capture them, and then after a while you can look for themes that might drive some hypotheses. Then you have something more specific to google for particular experiments.
For a bit of a different approach to finding inspiration, it might be fun to look at some of the crowd-funding science projects, (like scistarter.com/finder) and games (Google something like "crowd source science games" and you'll start with a huge list on Wikipedia, or there's a couple of cool ones described at scienceadvice.ca/en/feature/past-features.aspx?id=100&utm_source=Council+E-News+Winter+2014+English&utm_campaign=English+E-News+-+winter+2014&utm_medium=email).
Curiosity also led me to mooch around Coursera one day (
www.coursera.org), where I immediately found a 6 lecture mini physics course on origins of the universe that I think DS10 would love. A little over his head, but seemed to be structured in a way that you can fully wallow in the ideas while taking the math as far as you are able. Could be a fun way to play with some advanced science in an area of particular interest, with no commitment or fuss about the level of instruction being too high.
Love to hear later what kinds of ideas end up capturing her imagination! Times like this I wish we were homeschooling too, and could really dive into these kins of things.