Use a Web Subject Directory rather than a search engine (like Google). A Web Subject Directory acts like a "Table of Contents for the Internet" and can save you time searching. Most Subject Directories are compiled by experts in various fields. Subject directories usually have a smaller number of sites. They are useful for browsing broad questions like "I need to find a science fair topic on …."
Naturally....adult supervision with any home science project is essential.
How can you trust what you see on the Internet? Anyone can and will post information on the Internet, so it is important to evaluate the quality of the information you find. Librarians agree that these are questions you should always ask about a web site:
See UW-Madison Libraries Judging Reliability and Relevance.
I love exploring science informally with kids. When my kids were little, summer was a great time to explore the woods and creeks of our local parks and arboretum. Jars of "speriments" filled our refrigerator and lined our window sills. Two of my most favorite memories are sketching pitcher plants in the "Arb" and launching pingpong balls into the elementary school hallway with my after school science club. I believe that adults can foster the love of discovery that can happen when kids and science get together.
Emily Wixson, original author of Science Projects for Kids