11 Perpetual Motion Toys for Science Lovers

Are you a lover of perpetual motion toys?

Well, thanks to Google's mysterious search algorithms, you're in the right place. You might have seen the swinging sticks in the movie Iron Man 2, and been intrigued since then. This article will feature 11 of our favorite perpetual motion toys, in that familiar clickbaity format that people have surprisingly come to know and love.

But before we start, what is perpetual motion exactly? Well, according to the source of all things true and un-editable, Wikipedia states perpetual motion is "motion of bodies that continues indefinitely. A perpetual motion machine is a hypothetical machine that can do work indefinitely without an energy source."

So does anything on this list come close to being a perpetual motion machine? Absolutely not. But some of these toys have a secret ingredient, batteries!

Of course a real perpetual motion machine does not exist, yet that hasn't stopped scientists from trying. Having helium in a superfluid state can certainly seem as if it could be used for perpetual motion, as it can rotate without friction. The superfluidity of the helium is however lost once the helium heats up. Don't worry though, nothing on this list requires superfluids for them to work. 




revolving office toy - desk mess

Number 1 on this list requires the secret ingredient of batteries. The batteries power the electromagnet in the base, which either attracts or repels the permanent magnet at the bottom of the pendulum. 

But hang on, what's an electromagnet

An electromagnet is similar to a permanent magnet, however it has an electric current going through it that can change the strength of the magnetic force. As the pendulum is moving closer to the base, the electromagnet sends out an attractive force. Once the pendulum starts moving away from the base the electromagnet sends out a repelling force. This constant attraction and repulsion allow the pendulum to overcome the friction and drag forces it experiences, allowing the perpetual motion toy to seemingly go on forever. 

But how does the electromagnet know when to attract and repel?

The electromagnet has a transistor that acts as an oscillator, whose period is set by the pendulum. What that means is basically the electromagnet is linked up to the position of the permanent magnet in the pendulum, so they will always be in sync. 




newton's cradle - desk mess

No batteries required for this perpetual motion toy! The downside for this is that it can't overcome the friction forces from hitting the other balls, and the drag forces when going through the air. 

That isn't to say that hours of fun can't be had with this newton's cradle though. Every single combination and arrangement of balls will produce a different outcome. 

Release 1 ball and you'll get 1 ball swing up from the other side, while the 3 in the middle stay still. 

Release 3 balls and you'll get 3 balls swing up from the other side, leaving no balls in the middle to stay still. In fact, because of the number of balls swung, this will mean that the ball in the middle will be swinging constantly

Release 1 ball from each end at once, and you'll get a bouncing motion rather than swinging. 

There are so many more combinations to try out for yourself. 




sand pendulum - desk mess

The sand pendulum is one of my favorites on this list. It doesn't require any batteries, and leaves you with beautiful designs carved through the sand, like the one in the picture above. 

The tip of the pendulum only just touches the sand, so only a little bit of energy is lost due to friction. This means that the pendulum can be swinging for a few minutes. The gravitational forces and the forces from the Earth's rotation play a vital role in creating these beautiful and mesmerizing patterns. 




drinking water bird toy - desk mess

You might have seen this toy from The Simpson's episode where Homer tries to get it to do his work. What you typically should do to get it to work is to put the beak of the bird in water for a few seconds, starting the chain of reactions. Another thing you can try is to breath on the bulb containing the liquid. This will have the same effect. When the bird's beak becomes wet, the following happens: 

  1. Water will evaporate from the birds head, causing it to cool down
  2. This decrease in temperature creates a decrease in pressure (do you remember the gas laws from school?)
  3. This decrease in pressure causes the fluid to rise up the tube
  4. As the fluid rises up the tube, this causes the head to tip, as it is not properly balanced
  5. As the head tips, vapor bubbles travel to the head, forcing the liquid back down into the bottom chamber
  6. The process repeats




perpetual motion spinning top - desk mess

If you've seen the move Inception then you'll know what this toy is about. This one also keeps on spinning, but that's because of the batteries (or is it?)




desktop metal spinner - desk mess

A simple desktop metal spinner. It has been finely machined so the spinning motion generates very little friction, meaning the hypnotic spinning motion lasts for a long time. 




ferris wheel perpetual motion toy  - desk mess

This Ferris wheel perpetual motion toy is quite similar to number 1 on this list. It is also powered via electromagnets, causing the Ferris wheel to appear to spin forever. 




Another favorite of mine on this list is the Stirling engine. Place this onto your hot cup of tea, coffee or water, give the flywheel a gentle turn and watch it start turning faster and faster. 

But how exactly does it work? 

A Stirling engine uses heat (in this case, from a hot cup of liquid) and turns it into mechanical energy (spinning the flywheel). A Stirling engine contains a chamber of gas (air in this Stirling engine) that is sealed off (the drum looking cylinder at the bottom, with the moving piston).

The bottom plate that you can place on a cup of liquid slowly increases in temperature, which then heats the gas in the chamber, causing the piston to rise due to an increased pressure from the temperature increase. The piston in this Stirling engine is an insulated foam disk, so it helps in keeping the difference in temperatures of the two plates (one hot from the liquid, one room temperature from the air around it). 

Heat is lost through the heat sink (the top plate), which decreases the pressure, causing the piston to fall. This rising and falling of the piston turns the flywheel, as they are connected via a crankshaft. The turning of the flywheel builds up momentum, and stores energy as rotational energy. This rotational energy allows the Stirling engine to keep turning for a long time, which also helps keep the piston turning. 




metal gyroscope - desk mess

This metal gyroscope can be spun up and placed on its stand, while at an angle like in the picture. 

But doesn't gravity cause it to fall?

Yes, eventually it will. However, the angular momentum and gyroscopic effects will defy the forces of gravity until the drag and friction forces slow the gyroscope enough for gravity to become the dominant force. 




newton's balance figure - desk mess

Due to an imbalance in weight, these Newton's balance figures will wobble around in all different kinds of chaotic patterns. 

Each one of the eight different designs behaves in a slightly different way, due to them all having a different distribution in weight.  




revolving cosmos perpetual motion toy - desk mess

Similar to number 1 and 7 on the list, this revolving cosmos perpetual motion toy is powered via batteries, which in turn power the electromagnet. 

Rather than having just a pendulum like movement however, this rotates on three separate axes of rotation

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