Answered By: Barrie Hayes, MSLS Last Updated: Jun 22, 2017 Views: 1
Your use of a few copyrighted images from a Google search as part of a classroom presentation would fall under fair use in education. It is good practice to attribute the image in some way such as include a small URL below the image to the source or include a slide with "credits" at the end.
One other note. If you use the Google Images search, click on Tools and select Usage Rights. You can limit the search results to those by creators who have specifically licensed the work for reuse.