Depending on their solubility, solids can completely dissolve in liquids to form clear solutions, or form suspensions that still contain undissolved solid. Solutions of polymers often have a lower critical solution temperature; only below this temperature is the polymer completely soluble at all concentrations.
However, it is rare for non-polymeric mixtures to have a lower critical solution temperature because small molecules usually become more soluble as they are heated.
Osaka University researchers have now created a mixture of small organic and inorganic molecules that has a lower critical solution temperature. Their luminescent mixture is easily switched from a solution to a suspension and back again, simply by changing the temperature. The system, which has a different emission color depending on whether it is in the solution or suspension state, will be useful for the development of new thermo-responsive materials that change color when heated. The study was recently published in the journal Advanced Materials.
Read more.
The Worlds of our Solar System
If you put that ball on that machine while it wasn’t spinning, it would just roll straight down the lower sides.
The raised edges would keep it in the middle line, but it’s only controlled in one direction. By spinning it, you constantly alternate the position of the tall sides, meaning that the ball is held in the middle, never able to fall off.
Particle accelerators control particles in the same way. Magnetic or electric fields can only direct particles in one plane at a time, so to keep a beam of particles rushing down a particle accelerator in one focused stream, the current gradient must constantly oscillate. This means the particles are constantly held in place, never able to shoot off in one direction.
Here’s the same principle in action: these are tiny pollen grains being held in place by an oscillating field. Rods in the four corners of the beam establish a field that oscillates many times a second to keep the pollen trapped. If it didn’t constantly switch, the pollen would all fly off in one direction.
Watch the full film with Dr Suzie Sheehy for more.
light speed is, well, a lot: about 670,616,629 mph. If you could travel at the speed of light, you could go around the Earth 7.5 times in one second
Happy national periodic table day!
When an electron meets its antimatter twin, a positron, the two are annihilated in a tiny flash of energy. Two photons fly away from the blast.
Subatomic particles like photons and quarks have a quality known as “spin”. It’s not that they’re really spinning – it’s not clear that would even mean anything at that level – but they behave as if they do. When two are created simultaneously the direction of their spin has to cancel each other out: one doing the opposite of the other.
Due to the unpredictability of quantum behaviour, it is impossible to say in advance which will go “anticlockwise” and the other “clockwise”. More than that, until the spin of one is observed, they are both doing both.
It gets weirder, however. When you do observe one, it will suddenly be going clockwise or anticlockwise. And whichever way it is going, its twin will start spinning the other way, instantly, even if it is on the other side of the universe. This has actually been shown to happen in experiment (albeit on the other side of a laboratory, not a universe).
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