I really want to like this guy, but he seems to slightly misunderstand every topic he presents. In this case, the pulleys work by dividing the work, making a ratio. Same as increasing the length of the lever on one side of the fulcrum. Simple. Instead we get confused ramblings about rope pulling and other verbose half-understandings of tension mechanics. Nevermind the dubious value of including your children in your video, a simple scale would have been much more demonstrative. A few more hours of preperation before hitting record would make these videos much more useful for teaching. Instead we are just left with his enthusiasm and some hasty examples, and patronizing 'explaination' not even useful for most children.