You must always include a Bibliography with your research assignments.
Check out Ergo for easy to understand information on how to write a bibliography.
There are some great tools available online to help you, try this online referencing tool.
Search World Book Online for information on different scientists. You can get a password to access this database at the library.
Search Science Online for biographical information on many scientists.
Click on Key People for lists of scientists.
Search Weblinks for excellent websites on different scientists.
Search You Tube for short biographical films that may be available on your chosen scientist.
This one is on Marie Curie and her groundbreaking work on radiation.
This one is on Albert Einstein and his groundbreaking work in physics.