Law: a description of how something happens; always happens the same way.
Example: The Northern Hemisphere experiences a significant ice age every 10,000 to 20,000 years.
Theory: a well-tested explanation of how something happens that is backed by evidence (key words: because, caused by, the reason is, due to, etc.)
Example: The Northern Hemisphere will experience an ice age after this period of global warming, because cold water released from melting polar ice caps will alter the Gulf Stream in the ocean and the Jet Stream in the air.
Click link to download Vocabulary Assignment #2 – Theory vs Law worksheet