Khan Academy
Khan Academy: Classic Experiments: Dna as the Genetic Material
Learn about the experiments by Frederick Griffith, Oswald Avery, Alfred Hershey, and Martha Chase that led to the discovery of DNA as the genetic material.
CK-12 Foundation
Ck 12: Biology: Dna, the Genetic Material
[Free Registration/Login may be required to access all resource tools.] Describes how DNA was discovered.
Other
University of Cincinnati: Dna Structure and Function
This site explores the history and the science of DNA. Content also examines and considers the possibilities of genetic engineering and mutation.