Jim Sellers (Oregon, WI) built this lovely Slink-O-Matic Slinky-playing machine. Why? Why not? D’uh.

It “slinks” a slinky for you, at times when there are no stairs and you just have to…

Also useful in determining whether one is in the northern or the southern hemisphere. Due to Coriolis forces it will “slink” from right to left in the northern hemisphere and from
left to right in the southern hemisphere. ;-)

Why should The Most Useless Machine have all the fun?

Jim Sellers

Gareth Branwyn

Gareth Branwyn

Gareth Branwyn is a freelance writer and the former Editorial Director of Maker Media. He is the author or editor of over a dozen books on technology, DIY, and geek culture. He is currently a contributor to Boing Boing, Wink Books, and Wink Fun. And he has a new best-of writing collection and “lazy person’s memoir,” called Borg Like Me.


    For your next project, how about one that will play with ANY slinky. One like that, or a small metal one, or plastic one. (are there other types? carved wood?) I was thinking by using weight, or possibly tension, to know when to start the opposite cycle. And it would need “hands” to hold and grip the slinky. That would be even cooler. I would try to make one if I could.

  • engunneer

    I don’t think this can be used as a hemisphere sensor. Water doesn’t swirl the other way in the southern hemisphere, unless the sink is designed to make it go the wrong way.

    the argument basically is this. If water swirls one way in the N.H. and another way in the S.H., there must be some point in between where it switches direction. Either it would have to be a step change (move across the equator and it suddenly changes) or a smooth change (water doesn’t swirl near the equator, and swirls faster closer to the poles). since neither of these are true, the swirl (or in this case the direction of slink) can’t change based on which hemisphere it is located in.

    • Wes Nixon


  • Adam E

    Coriolis forces act over long distances and are not strong on the small scale. Slinkies and whirlpools will go whatever direction suits them. It’s easy to change the direction of a whirlpool with your hand. Toilets often go one way because of the way the holes under the rim are manufactured. A different direction in the southern hemisphere would simply be a different manufacturing process dominates down there.

  • Robot Mike

    Jim made me my very own Slink-O-Matic. I have no stairs in my house so it is indeed a very welcome machine. While I’m sure it can solve differential equations with ease, I just use it as a hypnotic brain dissolver. Thanks Jim!