Education.com is a great resource for homeschoolers. One section that I have been taking advantage of lately is their vast amount of science fair projects. My daughter is a hands-on kind of kid and many of the concepts taught in her Apologia science book can be demonstrated with science projects I find on Education.com's website.
You don't have to be planning a science fair (although homeschoolers can get together to have one) to use these experiments. Simply search the subject your child is learning about and scroll through the available project until you find one that interests you.
If you find projects you think will work for you at a later date, you create a collection and then save the projects to that collection. I actually am an author for Education.com and have a collection of my own science fair projects. You can see how it works here: Science Fair Projects
Make sure you rate each project as this will help other homeschooling parents in selecting an appropriate project. I always check project ratings and comments before I dive in to completing any science experiment. Sometimes parents who have tried the experiment have an idea as to how you can make the experiment continue on.
Anything that spurs my daughter to want to continue testing new theories is a bonus. In fact, you'll find many of the science experiments on Education.com actually end with ideas on how you can further explore the topic at hand. In conclusion I highly recommend Education.com for homeschoolers and homeschooling parents who want to expand on their science curriculum.