Part of finding what you're looking for is choosing the best search terms, or keywords, for your search.
For your lab, you've collected data on how fast plastic animals (representing various species) can cross a tub of water (unaltered, and after altering their fins, feet, etc. with additional pieces of plastic). Now, you'll have to find related primary scientific articles to use as sources in your lab report's introduction and discussion.
Start by writing a one-sentence summary of what your are looking for. Are you going to find primary articles about plastic wind-up toys in a tub of water? No! Think broadly here:
Now, divide your search into its main concepts:
After you have your main concepts, brainstorm as many synonyms and related terms (broader or more narrow) as you can think of:
Now that your have some search terms, test them out in the library's article databases.