Making Harry Potter’s Invisibility Cloak

Making Harry Potter’s Invisibility Cloak

Well maybe not quite the cloak itself but we can certainly make things disappear with optics! Have you ever wondered how a lens actually works?

Optics is one of the most fascinating fields in science as it allows exploring minds to engage and immediately see the results of their experiments. Over the years we have constructed kits for students to present as science projects such as telescopes and magnifying systems. We’ve even helped to make a room sized camera obscura for a HSC student with fantastic results!

A little while ago an interesting experiment came across our desk regarding the Rochester cloaking device that uses lenses to render objects inside the system invisible (Click here for the research). Now, it just so happens that we have access to a ready supply of lenses and Grant was more than willing to spend some time working with the experiment to replicate the results and needless to say it left him inspired.

Depending on interest, we are looking at holding classes where we will be conducting a series of experiments in our front window and everyone is welcome to come and join in. The first will be a basic imaging exercise, followed by dispersion experiments and finally our Rochester Invisibility Cloak. There will be explanations of the relevant phenomena by UNSW adjunct senior lecturer Grant Hannaford and everyone is encouraged to get involved with setting up and running the experiments. Our results will stay in place so that the people of Bowral can marvel at your scientific prowess!

We are also available to come to your children’s school to deliver classes on all aspects of optics and photonics from primary school to HSC level content.

Please register your interest by making contact with us today.

Here at Hannaford Eyewear we love our optics and give expert advice every time.

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*Featured image from

Eye Care In Sports

Sports, Safety & Your Eyes

While all sporting activities carry a degree of risk there are some that are more prone to eye injury than others. It is important to consider this when taking up a sport as eye protection, just like any other piece of sporting equipment is vital to not only safety, but success in your chosen pastime.

In this post we will take a look at a two of the sports that have shown up in our practice.

Racquet & Stick Sports

One of the more obvious risks for racquet sports is the racquet itself, after all it represents what is effectively a club of some description that is used to hit a projectile or ball. Risks from being struck by the racquet centre around impact to the face which can cause damage to the soft tissues and bones of the skull. At the most basic we look to impact resistance lens materials to provide a first layer of safety but there are a number of frame options available to us now that are often tailored to specific sports.

While many people would look at the above picture and say that the cricket ball is the most dangerous, in real terms it falls behind the hockey ball, which is much harder, and the innocent looking squash ball. The reason why the squash ball is so dangerous is not just the high speed at which it travels, it is the size of the ball that does the most damage. Compared to the human eye they are almost exactly the same dimensions which means that an impact upon an unprotected eye can cause devastating damage as it fit’s easily into the eye socket. This is similar to golf although the placement of the participants on the course makes injury much less likely than in squash.

Karate/Contact Sports

This one may seem obvious but a quick look at any dojo will show that it is often overlooked. Spectacles are not the ideal solution when performing hand to hand combat sports but when weapons are introduced it is well worth considering some sort of protections, particularly if bunkai or paired work is being undertaken. If we look closely at the shape of most martial arts weapons they are, by design, dangerous. Even most wooden staffs have a diameter that fits the eye socket and of course swords and sai are designed to cause penetrating wounds.

All this considered it is worth examining safety equipment for use when performing martial arts. There are a number of options from the simple safety sports frames to more comprehensive solutions such as those below.

The benefit to full head gear is the overall protection it affords, however, if wearing contact lenses there may be issues with sweat and discomfort as it is not possible to access the face without removing the head gear. Much like the lenses mentioned before the face shields here are made from impact resistant materials to avoid fragmentation of the plastic on impact.

Vision Correction In Sports

Contact lenses can be an ideal solution for sports. It has many advantages over spectacles including:

  • better peripheral vision
  • unobstructed field of view
  • less likelihood of fogging up and getting splattered compared to spectacles
  • less chance of injury (a hit to the face with spectacles may cut the skin)
  • more stable vision
  • better compatibility with safety equipment


You haven’t spoken about my sport……..

We will endeavour to discuss as many sports as possible in future posts. However if you have a specific question, don’t wait and see, just contact us today and we’ll find the solution that’s just right for you.