You are not a beginner, SomeCallMeChrisさん.

Note: Just randomly I tested myself on a vocab "black hole" - my guess from audio was "ブラクホル", auto caption had "ブラックホール". Well, the later spelling is what you will find in dictionaries and my guess was wrong. On that occasion auto captions turned to be useful.

They're very short videos (about 5 min), but I like this channel
http://www.youtube.com/user/jstsciencechannel