They taught you wrong: there's way more than solid, liquid, gas
Is it solid, liquid or gas?
An interesting question to ask when looking at your hair is what kind of material it is made of. You were probably taught at school that all matter is solid, liquid or gas. As a hair clearly isn't liquid or gas it must be a solid, but something so flexible and pliant does not really fit with our immediate concept of solid. We tend to think of a solid as rigid, not pliable. Sand is another good example of a substance that doesn't fit comfortably with simplistic classifications. Think of a fistful of sand - indubitably sand is made of solid particles, yet it runs through your fingers like a liquid.
Theoretical view at states of matter
We can feel better these states of matter from one of the few substances that we experience as solid liquid and gad - water. From it we learn that the distinction between the three states of matter is twofold. The atoms are typically further away from each other and they are typically moving faster as we go from solid to liquid to gas. All atoms and molecules move, but in a solid they jiggle about in a well - established framework of bonds - electromagnetic links between molecules. In a liquid, there are still bonds, but they are less substantial and have no stable structure. In a gas the molecules act pretty well independently.
This makes it sound as if there is a continuum between states, but they are clearly defined. It's true that as a liquid, for example, molecules of water will constantly be escaping into gaseous form (evaporating), but if you want to turn a body of water into gas you have to heat it to the right temperature, the boiling point, and then give it extra heat (the 'latent heat of boiling') to remove the final bonds and let those molecules free.
The fourth state of matter
The science you were taught at school probably stopped with the Victorian idea of there being three states of matter, but in fact there are five states altogether. The fourth is one that you have experienced many times - it is a much more obvious state than gas - but because our school science is so strongly locked into the nineteenth century worldview, even many adults do not know it exists, except as a label in relation to large screen TVs. It's plasma.
How many states of matter you were aware of before reading this article?
Meet the plasma
Plasma in the physics sense is the fourth state of matter, the one that comes beyond gas. A plasma is something more like a gas than a liquid, just like a gas is more like a liquid than a solid, but it is still something else; a different state of matter.
I wrote that plasmas are more obvious that gases because they are usually highly visible. The Sun is a huge ball of plasma. Every flame contains some plasma, although the flames we usually encounter are fairly cool in plasma terms, so usually consist of a mix of plasma and gas. Just as a gas is what happens to a liquid if you continue to heat it past a certain point, so a plasma is what happens to a gas if you continue to heat it far enough.
Experiment - The state of custard
We usually think of materials changing state as a result of variations in temperature. But pressure can also have a dramatic effect on some materials. Funny experiment to test this:
- Mix custard powder with water until you get a yellow liquid and pour it into a bowl.
- Put your fingers into the liquid few centimeters apart and squeeze them - the liquid becomes a dry powder under the pressure of your fingers.
- Keep the pressure up and try lifting it out of the bowl.
- Relax the pressure and mixture will return to liquid and drip from your fingers.
Make enough of this substance to fill a pull, and you will be able to walk on the surface of it.
Plasma at quantum level
Imagine we take a room of gas and start heating it. As the gas gets hotter and hotter, the electrons around the atoms in the gas get more and more energy. Eventually some have enough energy to fly off and leave the atom behind. Most atoms have a natural tendency either to lose or gain electrons. Atoms that easily lose electrons do so, and end up as positively charged ions. Atoms that easily gain electrons hoover up the spare ones from the positive ions and end up as negatively charged ions. Ions are just charged atoms with either electrons missing or electrons added. A substance that had been heated so far that its atoms become ions is plasma.
The fifth state - enter the condensate
The fifth state of matter is a Bose-Einstein condensate. This is a state down the other end of the temperature scale from plasma. In fact, before we visit the condensate, it's worth just briefly thinking about temperature.
What is temperature?
It's how hot something is - fair enough. To heat things up we have to put energy into them. But what is happening as we do? The atoms or molecules in the material speed up. Even in solid, atoms jiggle with energy. In a liquid they move about, while in a gas they positively rocket around the place.
Bose-Einstein condensate is when particles in a matter stand perfectly still. They don't move at all. Practically this is impossible because atoms can never stand their ground absolutely still. But in theory, we know the exact temperature needed for such a phenomenon to happen. This temperature is called absolute zero; it is around -273.16 in Celsius.
Bose-Einstein condensate properties
Although we can't make matter to reach this temperature, when we are getting closer to it, materials begin to behave very strangely. Some substances become condensates. A condensate is a state of matter where the particles that make it up lose their individuality. This results in a strange behavior like super fluidity, where the substance has absolutely no resistance to movement. Super fluids climb out of containers of their own accord, because there is no resistance to the random movement of the molecules. If you start a superfluid rotating in a ring it will go on forever... Then there are superconductors, which have no electrical resistance.
Condensate is halfway between normal matter and light itself, it can interact with light in a strange way, slowing it to a crawl or even bringing it to an effective standstill. This weird mix of light and matter is called a 'dark state'.
Mystery of black holes
- A closer look at Black Holes
How black holes form? What is a black hole? Common mistakes about black holes. Why black holes are important? What is event horizon and singularity?
Meet one of the strongest drugs - LSD
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Psychological effects of LSD. LSD history. Physical and sensory effects of LSD. How LSD works? Tips, advices for LSD trips.