Weizmann Institute scientists apply the principles of white color and white noise to create a white smell
You can see the color white; you can hear white noise. Now, Weizmann Institute researchers show that you can also smell a white odor. Their research findings  appear online this week in the Proceedings of the National Academy of Sciences (PNAS).
The white we see is actually a mixture of light waves of different wavelengths. In a similar manner, the hum we call white noise is made of a combination of assorted sound frequencies. In either case, to be perceived as white, a stimulus must meet two conditions: The mix that produces them must span the range of our perception; and each component must be present at the exact same intensity. Could both of these conditions be met with odors, so as to produce a white smell? That question has remained unanswered, until now, in part due to such technical difficulties as getting the intensities of all the scents to be identical.
A research team in the Neurobiology Department, led by research student Tali Weiss and Dr. Kobi Snitz, both in the group of Prof. Noam Sobel,  decided to take up the challenge. They began with 86 different pure scents (each made of a single type of odor molecule) spanning the entire “smell map,” diluted them to obtain similar intensities and then created blends. Each blend contained a different mixture of odors from various parts of the smell map. These blends were then presented in pairs to volunteers, who were asked to compare the two scent-blends.
The team discovered that the more odors that were blended together in the paired mixtures, the more the subjects tended to rate them as similar – even though the two shared no common components. Blends that each contained 30 different odors or more were thought to be almost identical.
The researchers then created a number of such odor blends, giving them a nonsense name: Laurax. Once the subjects were exposed to one of the Laurax mixes and became accustomed to the smell, they were exposed to new blends – mixtures they had not previously smelled. They also called some of these new blends &