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Until now, droplets were considered simple spheres of inanimate fluid, not capable of moving of their accord.

But researchers in Denmark have discovered that when alcohol droplets are in the right environment, they not only move on their own, but also navigate complex mazes.

By adding salt and alcohol droplets to a tray of water, the salt changed the gradient of the liquid, which in turn caused the droplets to move towards it  - similar to how a ball runs downhill.

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The droplets (pink) were manipulated by researchers at the University of Southern Denmark. Each droplet was guided through a complex maze of water towards salt (yellow). The droplets moved because the salt changed the gradient of the water, which caused the droplets to move it, similar to how a ball runs downhill 

'Salt is the stimulus that makes [the droplets] move,' explained Professor Martin Hanczyc from the University of Southern Denmark.

'They move because the salt gradient provides a different energy landscape.'

He continued that when a ball, for example, is laying on a flat surface that suddenly becomes hilly, the ball rolls to the lowest point possible.

The droplets behave in a similar way.

'Without a salt gradient, every direction in which a droplet might move looks the same – flat,' Professor Hanczyc continued.

'But with a salt gradient coming from one direction, the droplet can move energetically downhill into the salt gradient.

'And stronger salt concentrations will attract the droplet more.'

During tests, Professor Hanczyc discovered the alcohol moved as if it is attracted to the salt because of this change in gradient.

He filled a tray with water before constructing a complex maze and placing salt solution in one corner.

In the corner, furthest away from the salt, Professor Hanczyc added a droplet of decanol.

Without touching the tray, the decanol began to move on its own around the maze, taking the shortest route possible to reach the salt.

'The system itself is very simple yet it displays sophisticated behaviour', explained Professor Hanczyc.

Science experiment shows alcohol droplet navigate a maze

Using more salt increased the gradient, which increased the droplet's speed. In addition, the droplet was able to distinguish between salt sources of different concentrations and temperatures, and when the droplet arrived at the source it physically fused with the salt and reacted with it (graphic of droplet movement pictured)

The research is useful because it reveals that droplets can be led to certain targets.

This could be used to physically move the liquid to a place where it's needed, to deliver medicine inside the human body, for example.

It could also act as a lubricant in a machine, and target an area that needs lubrication.

Elsewhere, it could be used to move flavour through food.

The same droplet can also be made to migrate towards salts at different positions added sequentially.

In addition, the droplet is able to distinguish between salt sources of different concentrations and temperatures, and when the droplet arrives at the source it can physically fuse with the salt and react with it.