"Power of the Pendulum - Proof of Ultra-Efficiency?" This video could be shorter, but if you have extra time on your hands take a look. He's got a pendulum mounted on a stand that is not fixed to the table. When he blocks the pendulum from swinging and strikes the apparatus the whole moves a small amount. But then when he unblocks the pendulum and strikes the pendulum, which then strikes the upright, the whole moves by a much larger amount. It doesn't make sense to me that transferring energy through a pendulum would be so much more efficient than a direct blow to the apparatus. To do the striking he employes a thing termed "measuring instrument with piston mechanism". I have never seen one of these, but the implication is that this instrument limits the amount of energy that can be imparted with it to a fixed amount, regardless of the number and force of the blows you make with it. The piston, it's implied, will "sum" the energy, coming to a stop at the end of the cylinder when the limit is reached. That implication strikes me as the erroneous one. If the air is escaping through a small orifice (it's not clear to me if it is) then the harder you hit with the thing, the more it will act like a spring. The air would just compress, then expand, driving the piston back out. He seems to be hitting much harder in the second set up.