3 ways to get your fidget spinner to spin longer

By Wendy Sadler

You’d have to be living under a rock to have avoided the craze of the fidget spinner. It’s the craze that has taken playgrounds by storm, and if you haven’t tried one, you’ll find they are surprisingly pleasing to play with!

But there’s also loads of science going on in fidget spinners that relates to all sorts of unexpected things. So if you want justification to your teacher that they’re educational, read on…

3 ways to get your fidget spinner to spin longer (and the science behind why they work)

  1. Give it the biggest possible push
  2. Reduce the friction as much as possible
  3. Put weights at the edge of the spin

1. Give it the biggest possible push

A very famous scientist called Isaac Newton told us some important things about forces and motion. His three laws of motion pretty much explain how things move. His first law sounds very obvious but is the first step to making your spinner go. Newton’s first law says that things either stay still forever, or carry on moving at the same speed forever unless acted on by a force. If a ball is sitting on a floor it won’t move on it’s own unless you apply a force (usually by kicking it!). Likewise, your fidget spinner won’t do much whilst you hold it, unless you apply a force. The bigger the force the faster it will go – and the longer it will spin.

If you want a way of finding out how fast your spinner is going, you can use a neat trick from Matt Parker (Stand up Maths) that uses sound to measure the speed.

2. Reduce the friction

what is inside a fidget spinner

A fidget spinner is designed so that the outside section, or arms, move around a central axle. But then another force comes into play.

How do we know?

Because if there were no force, the spinner would go on forever! The force that slows the spinner down is called friction, but the best spinners have very low friction so that they go on….and on…and on…

Inside the middle of the spinner is a channel of ball bearings. These roll around to reduce the friction between the moving parts. Both the balls and the channel can be made of either steel or ceramic. Ceramic balls with a ceramic channel are thought to give the longest spin time because ceramic is the harder material. The harder the material is, the less the balls change shape when they spin, and even though steel is very hard, ceramic can be three times harder! Hardness matters because energy is wasted if the balls change shape at all when spinning. If energy gets used in changing the shape of the balls then it isn’t used in the spinning, so the spinning won’t go on as long. You can see a comparison of steel vs ceramic balls in a spinner here.

3. Put more weight at the edge of the spin

Have you ever wondered why there are extra circles of bearings put at the ends of the fidget spinner arms? Not only do they allow you to do some extra tricks, but more importantly they add mass at a distance away from the centre of the spin. Spinning objects have a thing called ‘rotational inertia‘. Inertia is to do with how easy it is to get something moving, and how hard it is to make something stop. A train has high inertia. It is hard to get it moving – but if it is moving at speed down a hill – it is also very hard to stop. This is related to the mass of the object.

When something is spinning it also matters where the mass of the object is. An object has more rotational inertia if the mass is as far away as possible from the centre of the spin.

So the heavier the mass (or weights) on the arms of your fidget spinner the bigger the inertia, and the longer it will spin. This is also why metal spinners can spin longer because they have more weight in the arms than the plastic versions. You can find more details about this here if you want.

For a super large fidget spinner, check out what might be the largest fidget spinner in the world here.

We trawled all the spinners in our house and tested them for which had the longest spin, so here’s one of our little SMS-ers to challenge you to a fidget spinner endurance test…

sms group shot with props smallWe are science made simple, a social enterprise who perform science, maths and engineering shows to schools, festivals and public audiences.

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Posted in Activity, Exploring Science, Physics