Obedient fish. Effective trick and its solution

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EFFECTIVE FOCUSES AND THEIR CLUES
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Obedient fish. Focus Secret

Spectacular tricks and their clues

Directory / Spectacular tricks and their clues

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Focus Description:

Show a glass jar with a rubber lid and three-quarters full of water. A plastic fish swims in the water.

Hold the jar still, and the fish will suddenly begin to rise and fall, as if following your inaudible orders.

Focus secret:

Focus Obedient fish

To make this trick unmistakable and effective, the stretched elastic band that closes the top of the jar must be thin. Press your fingers on top of this gum, then the pressure inside the jar will increase and the fish will go down. As soon as the pressure is loosened, the pressure from above will weaken and the fish will go up. The fluctuations of the fish up and down depend on the neck of the jar - the wider it is, the greater the amplitude of the oscillations.

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Economical Solar Powered Water Purifier 09.02.2017

The lack of drinking water is one of the most important problems in the world, even if in Europe it does not yet feel so acute. Qiaoqiang Gan, an engineer at the State University of New York, and colleagues have developed a solar-powered watermaker that costs as little as $2 per square meter of consumables.

"This will allow people to get their own clean water, just like they get electricity from rooftop solar panels," Liu said. The speed of desalination is of great importance - current devices must have an area of at least 6 m2 in order to supply one person with a sufficient volume of drinking water during the day. The problem is the huge energy losses for heating water.

Therefore, in recent years, two approaches have been used to increase efficiency - either heat only the top layer of water, or use nanomaterials to collect solar energy more efficiently. The second is technically preferable, but orders of magnitude more expensive - nanomaterials cost hundreds of dollars per gram, and there is no one in developing countries to spend that kind of money on desalination for everyone.

The new device has three main components: first, fiber-rich paper (like the one used to make money) coated with a black layer of carbon (this is a cheap powder left after the incomplete combustion of oil or tar).

Secondly, a bar of Styrofoam (disposable coffee cups are made from this material), cut into 25 lightly joined pieces. they all float on the surface of dirty water to prevent the water from overheating in the sun. These sections are covered with the aforementioned paper, the edges of which are lowered into the water. Accordingly, water, due to the capillary effect, rises up the paper and evaporates there.

Thirdly, and finally, it is an acrylic coating that collects evaporating water. From here, the water enters the clean water tank.

Gunn and his colleagues claim that the installation is 88% more efficient in collecting and transferring solar energy into water. As a result, a device with an area of 1 m2 produces 1 liter of water per hour. Now common commercial devices need 4 hours for the same result.

Most importantly, the device is very cheap. Gan estimates that it costs about $1 per square meter - compared to $2 for devices that use lenses to focus the sun's rays. It is enough for a family of four to spend about $1,6 dollars to have the minimum required amount of clean water.

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