Invisibility Cloaks

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Until recently, the ability to make something disappear from view has only existed in magical stories. In the Harry Potter series of novels by J.K. Rowling, Harry Potter uses a Cloak of Invisibility to sneak into forbidden areas of his school and remain unseen, and in Star Trek whole starships can seem to disappear by using a cloaking device. Scientists, however, may be getting closer to inventing a real-life invisibility cloak!

How we see

In order for humans to see, there must be light. Light hits an object and bounces off (reflects).

This light enters our eye through the pupil, the black hole in the center. Then, in the retina, the light is converted into electrical impulses which are sent along the optic nerve to the brain which then interprets what we see. Learn more about how the eye works through this interactive site.

By thinking about the important part light plays in being able to see, scientists have worked out how to hide objects by bending light around them.

 

How to make things invisible!

Up until now, this technology has only allowed tiny objects to be hidden, but scientists from the German Karlsruhe Institute of Technology (KIT) claim to have built an invisibility cloak big enough to hide objects like phones, keys or a wheel of cheese.

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To use the cloak, objects are put inside the small, long box that is coated with a special paint. The box bends light around it, meaning that the objects placed in it disappear from sight. The KIT scientists found a problem in that this meant that some of the light had further to travel around the object. Covering the whole box in a special light-scattering material helped them to overcome this and, because of the way that it is built, the cloak can be easily transported.

It may be a while before we are able to buy actual invisibility cloaks in the shops but who knows – objects could soon be ‘disappearing’ in a classroom near you!

 

Inquiry – Digging Deeper

Light refraction offers some amazing possibilities for creating light without the need for electricity. Watch the following video to learn how plastic bottles are used to create light in buildings in the Philippines.

If you are interested in refraction, you will love this activity for children: Create your own sunlight box!