Continental drift is one of the consequences of plate tectonics. The continents are attached to one or several of the moving plates.
i still don't get how they're different. What are 4 differences between them?
P.S. Try these sites:
3. (Wikipedia): http://en.wikipedia.org/wiki/Plate_tectonics
4. (Yahoo answer to your question): http://answers.yahoo.com/question/index?qid=20071003194507AAeReoF
5. (part II of #4): http://answers.yahoo.com/question/index?qid=20070624123638AAx9iMy
I would have said that Plate Tectonics is a theory "that explains the global distribution of geological phenomena such as seismicity, volcanism, continental drift, and mountain building in terms of the formation, destruction, movement, and interaction of the Earth's lithospheric plates."
Whereas Continental Drift is a geological phenomena than can be measured and recorded. Plate Tectonics is one of several theories that have been proposed over the years to explain Continental Drift another example is a theory based around Centrifugal Forces, but I can't remember the details.
I like Dr Russ's answer. Mine was rather off the top of my head, and I am not a geophysicist.
Plate tectonics is a fairly recent (middle 1900's) theory due to Wegener, now widely accepted, while continental drift was known for over a century before that, and is an experimentaly observed fact. Like all good theories, Plate Tectonics helps explain other phenomena as well, such as the volcanic and earthquake-active "ring of fire" around the Pacific Rim, the formation of new mountain ranges, and release of hot gases at sea-floor subduction zones.