Back To The Future fans prepare to get excited… Hendo creates the world’s first hoverboard prototype. 

Able to float one inch off the ground, the Hendo hoverboard creates magnetic fields that keep it in the air. The only issue right now is that the dream of emulating Marty McFly and sailing across open areas is still some way away; to work around the established theories related to magnetic fields and levitation, the board can currently only function in specially-designed skateparks that stabilise the field. Still, the movement is seamless and directional movement is based on nothing other than the user’s own lean as seen in the films. It’s one step closer guys! 

See more of the project or offer support at their Kickstarter page: here. 

Hoverboards are here

‘Yes, but where are the hoverboards?’ That has been a common refrain from frustrated gadget lovers as the technological advances piled up in the years since the release of Back to the Future II in 1989.

As we all know, our protagonist Marty McFly ventured forward in time in the second instalment of the Back to the Future franchise to 21 October, 2015, and got his hands on a hoverboard, which went on to play a rather important role in the film.


It is here: The Hendo hoverboard

Now, in an amazing feat of both engineering and marketing, Californian Company Arx Pax has announced it is about to win the pop culture version of the Space Race by producing hoverboards that will be ready for shipping on 21 October, 2015.

A Kickstarter campaign has been launched for the Hendo board and already $207,485 has been raised towards the $250,000 goal. There were 10 working Hendo boards available for pledges of $10,000 or more and these have already been claimed.


Wow: Marty McFly discovers the hover board in Back to the Future II

When McFly tries to ride the board over water and fails, Data famously calls out, ‘Hey McFly, you bojo, those boards don’t work on water!’ It is a similar case with the Hendo, as it can only hover over non-ferromagnetic metals like copper, silver or aluminium.

Arx Pax is light on the details of the Magnetic Field Architecture technology, but the hoverboard’s four battery-powered disc-shaped magnets on its lower surface suggest it is floated through electrodynamic suspension.

The Kickstarter page mentions the designers developed a keen understanding of both Earnshaw’s Theorem and Lenz’ Law in order to develop the board.

While Earnshaw’s Theorem states you can’t simply float a magnet above another magnet without physical stabilisation, this can be overcome by switching the polarity of an electromagnet through the expenditure of energy.

Once the board is moving, Lenz’s Law explains another method of stabilisation through ‘eddy currents’. It says that these eddy currents create a magnetic field that oppose the magnetic field that created it. The law is effectively an explanation of Newton’s third law of the conservation of energy for magnetism – that for every action there is a reaction.

There are other ways to float things through magnetism, as we have seen a frog suspended through diamagnetic levitation in the past, and superconductors have been floating extremely cold objects for years.

So the hoverboard dream may soon be a reality, but only in specially-built parks and for those that have a lot of money to spare.

Where Arx Pax will most likely make its money is through selling its levitation technology to industry, rather than by mass-producing hoverboards.

James Perkins is News Editor of Materials World

Electromagnetism & Optics

Gauss’ law example
Cont’d from “Electric field example”

This post is best viewed on my blog, click here to be taken to its permalink.

Consider a tube of uniform charge density λ, length l and radius r. The electric field acts perpendicular to the surface of the tube.



We know from Gauss’ law that,

∮ E · da = Qenc/ε0

and we know that

Qenc = λ · l


E  ∫  da 

where “curv” represents the integral over the curvature of the tube and da = r dφ dl in polar co-ordinates. The limits of the integral become

0 < φ < 2π

0 < l < l

due to the spherical geometry. Therefore the integral becomes

     l  2π
 ∫  ∫  r dφ dl
    0  0 

⇒ E · 2πr = λ/ε0

∴ E = λ/ 2πr · ε0

This is a manifestation of the Meissner Effect. When a superconductor reaches a critical temperature (usually very cold, 1 - 70 K) it expels all magnetic field lines. So if you place it on top of a magnet, it will float. It will float on a cushion of magnetic field. Additionally it will experience almost no friction so if you make a circular track of magnets it will levitate around it for quite a long time. And look awesome doing it. That vapour trail isn’t propulsive. It’s just how cold that superconductor is, it’s condensing the air around it.

'Think how you love me,' she whispered. 'I don't ask you to love me always like this, but I ask you to remember.'

'You'll always be like this to me.'

'Oh no; but promise me you'll remember.' Her tears were falling. 'I'll be different, but somewhere lost inside me there'll always be the person I am tonight.'

—  F. Scott Fitzgerald, Magnetism

Magnetism by Ling Meng - "What I am trying to focus on recently, is combining Art and Science somehow."

Created by Ling Meng a Shanghai based artist these atmospheric photos visualise the invisible force of magnetism. What we are observing acting on these iron filings in these photos is specifically known as ferromagnetism.

The iron filings have domains scattered through them, which can be thought of as smaller magnets in themselves. When a magnetic field is applied these domains they turn their poles in the same direction, referred to as a dipole dipole alignment, resulting in a net magnetization. A really nice video explaining this and its function in transformers is here. There are lots more artistic ways of applying these fields have a look at this ferrofluid sculptre video for example

You can view the rest of Ling Meng’s magnetism photos and his other work on Flickr. Logikblok FB.

Past posts on magnetic levitation.


Ferrofluid travelling around soap bubbles towards a magnet

Ferrofluid is a fluid made of colloidal nano-sized magnetic particles suspended in a hydrophobic solution. Some home-made ferrofluid can be made from an oil base (like vegetable oil) mixed with tiny particles of ferrite (pure iron) which can be found in printer toners/developers. The ferrofluid moves around the bubbles first due to capillary action- but is then drawn through by a magnet.

The original source really needs to be viewed as it’s fantastic!

See it here.

'Think how you love me,' she whispered. 'I don't ask you to love me always like this, but I ask you to remember.'

'You'll always be like this to me.'

'Oh no; but promise me you'll remember.' Her tears were falling. 'I'll be different, but somewhere lost inside me there'll always be the person I am tonight.'

—  F. Scott Fitzgerald, Magnetism

Magnetic Levitation - Making Frogs (and other things) Fly

There are a few ways of making things fly but none more awesome than levitation.The first two gifs show a magnet levitating on a super conductor, which has been immersed in liquid nitrogen this repels the magnetic force. This repelling is stronger than the force of gravity and as long as temperature is retained it will carry on levitating (but not rotating as air friction eventually slows it)

The frog on the other hand is levitating by being surrounded inside a huge magnet about 100 to 1000 times larger than normal magnets. By being exposed to this huge magnetic field the atoms within the frog behave like small magnets creating their own poles and as a consequence floating. Pretty much anything can do this including water watch videos on making things levitate here.

Sources: YBCO & High Field Magnet Laboratory


ZeroN - Levitated Interaction Element of Awesomeness

When I was younger, I used to push two magnets together until I found that point where a bubble of repulsion formed between them. With the weak magnets I had access to, I could always overpower the repulsive force and push them together, but I was amazed that there was some unseen magic acting upon two physical objects.

Like all of us, I later learned it was the forces of magnetism at work. The ZeroN project from Jinha Lee at MIT takes that to a whole new level.

By using computer-controlled magnetic field manipulations, a metal sphere is suspended in mid-air. Even more, it can be made to follow complex paths, “remembering” and repeating actions. If that somehow isn’t enough, just wait until he lights it up like an orbiting planet, and demonstrates Kepler’s Laws! Dude blew my mind!

It’s an experiment in challenging how we perceive natural patterns of motion, and whether computers, when combined with materials, can alter the way we interact with the world around us. Most of all, it’s AWESOME.

( MIT Media Lab)



Company which specializes in levitating displays, which obviously has many creative possibilities. A video put together by brusspup embedded below:

Here is a collaboration with artist Mehreen Murtaza which employs the levitation tech for an artwork:

mehreenmurtaza has a Tumblr blog here

You can find out more about the Crealev company and their projects at their website here

Researchers have cleverly devised a way to make paper that is waterproof, bacterial resistant, and magnetic. By wrapping certain nanoparticles around the fibers of the paper, it’s properties can be changed. The researchers point to using iron oxide nanoparticles to make the paper magnetic, and using silver nanoparticles to repel bacteria. The implications this technology has on the future of food packaging and medical applications are astounding. 

Full story here.


This beautiful video showcasing the behaviour of magnetic putty is strangely soothing, which isn’t a bad thing right about now. Via Colossal.

Are the Earth’s Magnetic Poles About to Flip?

by Megan Thompson

Three European satellites launched Friday on a mission to study why the magnetic field surrounding Earth appears to be weakening.

The four-year study will collect data and map the field, which protects the planet (and us) from solar radiation.

Scientists say the field’s strength has weakened by about 15 percent in the last 200 years.

The weakening could be a sign of “polarity reversal" - when the field flips end-to-end, turning north into south. The phenomenon occurs every 200,000 to 300,000 years. But the last time the field flipped was almost 800,000 years ago.

The magnetic field is believed to be generated by the Earth’s molten iron core. The field reaches thousands of miles into space and creates a bubble around the earth. It’s what makes compasses work, and aids everything from navigation systems to animal migrations…

(read more: PBS - The Rundown)

image: ESA/ATG MediaLab