The music world is a richer instrument: scientists from Darmstadt have developed a method to make water droplets sound and to convert their frequency into a measurable and controllable sound by flowing through a narrow tube.
Instead of on the stages of this world, however, the new instrument will presumably remain in the laboratory: the method can also be used in medicine.
Water droplets can be controlled with the help of alternating current so that they can produce music!
This is what researchers at the Max Planck Institute for Dynamics and Self-Organization in Göttingen have now found out.
In order to convert the frequency at which the drops flow through narrow tubes into measurable tones, the scientists use a microfluidic chip of about three by three centimeters edge length.
Such chips carry almost a whole laboratory on a few square meters, and have been increasingly used in analytics for a few years.
Accurate control by alternating current
Through the thin tubes of the chip they let a water-oil mixture flow and put it under current. Since the water and the oil do not mix, the water floats in the form of drops in the oil.
The size and quantity of these drops can be controlled very precisely, the scientists discovered: using alternating current.
Depending on the level of the voltage, different water droplets are produced which flow through the tubes per second.
For example, 100 volts produces less and larger drops than at 1,000 volts.
This is so far that the droplets are only a few micrometers in size and can only be seen under the microscope.
These different drop frequencies convert the researchers into sounds.
They use the detour via the light, as they explained in the online scientific journal Scientific Reports.
Frequency is visible by laser bombardment This, in turn, works by placing the fluorescent liquid in the tubes with a fluorescent substance and illuminating them with lasers.
The drops reflect the light, which also makes their frequency visible.
The reflected light impinges on a photomultiplier, which is so sensitive that it can convert even the weakest light signals up to individual photons into electrical signals.
These are forwarded to a sound card and made audible.Valuable insights for medical diagnostic research It is more likely to be used in medical laboratories as a stage career for the new procedure.
Diagnostic methods are currently being tested using microfluidic chips.
Samples from patients are examined by including cells or even DNA in minute water droplets in the water-oil mixture.
The movement of the droplets must be controlled very precisely in order to sort their contents according to various criteria, for example.
The researchers at the Max Planck Institute have impressively demonstrated that this is an electrical issue, and thus made an important step in the further development of the medical chip labor.
An important detail in their findings is that, with the help of electricity, very many droplets can be controlled at once.
This is particularly useful in cancer screening, in which, among other things, it is relevant how many cells of the patient have already mutated.Redirected and thus made audible.