I never really understood how live catches work, and I recently stumbled upon a great slo-mo video that sheds some light on that mystery (sorry if this has been posted before, I haven’t been very active lately).
The usual handwavy explanation is that somehow the flipper stopping at the exact moment it makes contact with the ball somehow “deadens the momentum”, which sounds like hogwash, because where does the energy go, and how is this different from the ball bouncing into an already stopped flipper.
Here’s how it actually seems to work, based on the video:
- If a ball comes down to the flipper and you flip it away, the flipper makes contact with the ball not once but twice: On first contact, the ball presses the flipper down a bit, thus losing contact. At this point the ball has lost a lot of its momentum and may even stand still on the playfield. Its kinetic energy has gone into pressing the flipper down against an electromagnetic force moving it up. After that energy has been absorbed, the flipper continues to go up and hits the now more or less motionless ball a second time, thus flipping it away.
- If this happens near the end of the flipper movement, when the second contact happens the flipper isn’t moving up anymore, because it doesn’t go that far.
- Something that may or may not play a big part in this is the fact that on each flip the rubber completely separates from the flipper, and on a live catch sort of envelops the bottom part of the ball.
If someone’s feeling adventurous and wants to help science, you could glue the rubber to a flipper and tell me whether live catches still work.
Here’s the video, the flipper stuff starts about 10 minutes in: https://www.youtube.com/watch?v=Tmg5WOvPKpU