DIY Invisibility Projects

Seeing the invisible spectrum: 
(above: inferred light as seen from a webcam)
The human eye is only sensitive to the part of the spectrum that we call colored light. Similar to how some sounds are above or below the range of human hearing, many forms of light are also above or below the range of human vision.

The human eye is unable to detect wavelengths of energy known as inferred light. Specialized equipment can be used to view wavelengths beyond the human eye's capabilities. Some web cams are sensitive to inferred light and can be easily used to view something that would normally be undetectable to the human eye. You could light a completely dark room with inferred light and a person standing in that room wouldn't be able to see anything while an inferred sensitive camera in the same room would be able to see everything.

What we recognize as color is only our brains response to various wavelengths of light detected by the optic nerve. Different organisms detect light in different ways. For instance you may see a yellow flower but a bee will see blue. What color is the flower really? The flower is only reflecting wavelengths of light. You can interpret the color in any way but the light waves stay the same.

Color as humans see it is the result of white light, which is all the colored light combined, hitting a surface and that surface absorbs all the light energy which is then convert into heat energy accept for the color that the surface is. That one wavelength of light is reflected off and can be interpreted by the optic nerve of the human eye.

Invisibility, to human standards, could be achieved by manipulating a surface to absorb all wavelengths of light. That surface however would still be detectable by other methods such as radar and sonar, or if it accumulated any amount of non-light absorbing substances. Another method could be stopping light from even reaching the surface, perhaps by bending the light through or around the object.

The truth is, invisibility is a common part our every day lives. One example is air, air is composed of many invisible gases. you can feel wind but you cant see it because of the way the light waves travel through it rather than reflect.

Experiments you can do with Invisibility:

EXPERIMENT 1: Start by finding a location that is dark and large enough for you to enter such as a closet. Make sure that you can leave this location easily in case of emergency and proceed to light-proof the room. Enter the space with all interior lights off and check along the cracks of the door to make sure that no light is entering. If it is, use brown painters tape to block the spots that light is entering through. Repeat this process until the space is completely dark. The environment you have created is now light proof. Notice that you can't see anything. This is because there is no light to reflect off of anything and therefor there is nothing that you can see because no light is being reflected into your eyes. At this point, notice that you cannot see your hand even directly in front of your face. You are invisible! There is no light reflecting off of you and as long as you remain under these conditions, you will remain invisible.

EXPERIMENT 2: You can make air visible in a simple experiment. If you take a glass of water and blow bubbles into it with a straw you will be able to see the air as it rises to the surface, the air will appear shimmery and silver. The water changes the way the light waves hit the air and makes it visible. What this experiment proves is that by changing how a surface is affected by light you can control the visibility of that surface.

EXPERIMENT 3: Commercially available Hydrophilic water gel Growing Spheres are little polymer orbs that grow in water. They do come in colors so make suer that you get colorless ones for this experiment. They can be ordered from this site: Once you have your spheres, place two or three in a cup of water. Wait several hours until the spheres have grown to their peak size and you will notice that they are completely invisible when you put them in the water but when you take them out, they are clear and can easily be seen. As in experiment one, the reason for invisibility is that the water alters the way light affects the object. You may notice that if you put many fully grown spheres into one container you will be able to see some of the spheres. This affect occurs because the spheres on the outside manipulate light internally like a lens and changes the way it hits the spheres behind it.

EXPERIMENT 4: Extreme heat provides another way to change the way light reflects off surfaces. To conduct this experiment you will need a large metal container (an old garbage can works great), fuel to burn such as wood, a lighter or some way to start a fire, a ruler, a sheet of white paper and a black marker. Be sure to use proper safety methods during this experiment because you will be around very hot surfaces. Start on a day with plenty of sunlight. Sunlight is key for this experiment because it provides a strong source of light to bend. Start a fire in the metal container in a safe spot well away from houses and flammable material. Continue to build the fire up until you can see heat ripples rising off the top. These ripples have light bending properties slightly different to the water used in the previous experiments. Take your ruler and draw ten to twenty parallel lines (parallel means like this: ||||||||||||||||||||||||||||| ) on the white piece of paper. Have someone stand on one side of the fire while holding the paper in front of them. The other person must observe by looking through the distortions in the air at the lines. It will be observed that the lines do not remain in straight lines and appear to bend. Be careful during this experiment and regard all surfaces near or that have been in contact with the heat ripples as hot!

EXPERIMENT 5: This one is a bit more theoretical as it requires a bit more setup that is available to most people. The concept behind this is to delay the lighting off of a surface by making it travel a longer distance. Light can be bent and stopped but the speed of light remains constant. This can be proven because we know that many of the stars that we see in the sky now are only the light that was produced by stars that once existed. We see those stars now because it took the light so long to travel to earth that the star that made it is likely already exploded or collapsed. In simpler terms; it is as if someone fired a bullet at a target that was hundreds of miles away. Assuming that this gun could fire that far and that the person firing it was accurate enough to hit the target once the shot was fired it would be possible for the person holding the gun to put the gun back in its holster before the bullet reached the target. In order for someone to use this to create invisibility, they would need to use either coils of super long, super efficient fiber-optic wire or some sort of set of super-polished mirrors that would reflect the light back and forth billions of times. What this would allow someone to do is to capture light and move it somewhere else before it was reflected back out of the system. This method is of course theoretical because there are other factors to take into consideration such as making mirrors that are 100% reflective or micro-fiber-optic coils that would be efficient enough because any impurities would make them visible. The basic concepts behind this method are to stall the reflection of light so that an object can move faster than it is reflected because the reflection of light is what allows us to see it.