Children want to search the web to do homework; teachers are rightly skeptical about the reliability of information they will find. In my last post about homework I wrote about the public library’s databases . You can trust those. You can also trust websites created by reliable organizations.
You'll know them by their domain name--that part at the end of their web address after the dot. You can usually trust educational sites (.edu), government sites (.gov), and organizations (.org). Texas A & M University's website, for example, is www.tamu.edu . The portal for all federal government sites is www.usa.gov  . The United Nations website is un.org. 
Google’s 'advanced' search will let you limit your search to only those domain names you want and trust. Put your search term in the usual Google search box. When it comes up with a page of results, look at the search box at the top of that screen. At the right you'll see 'Advanced Search'. Click on that. (See 2nd image.) It will open another page (see 3rd image) that will give you options for setting the domain name. Type in .edu, .gov, .org .
This screen will also let you set the Reading level to beginning, intermediate, or advanced, address copyright licensing restrictions, and make other choices.