Crash Course is a YouTube channel that was created by Hank and John Green. Hank Green explains Chemistry, Ecology, and Biology. John Green explains US History, World History, and Literature. I really like the series of videos because they are only around 10 minutes long and the lesson gets taught in a creative, visual way that engages students.
The video embedded below is the latest lesson uploaded to the Crash Course YouTube Channel. Hank explains Unit Conversion & Significant Figures: Crash Course Chemistry #2