States of Matter 6/8/20

Science with Richard Bleil

Today’s blog should probably be about politics, but with the news of the day I really find it difficult to write anything without using words that frankly are not appropriate for the tone I’ve set for this blog. With the repeal of college loan forgiveness for scam universities (one in particular I won’t mention because it was started by the president) and continuing protests and more in the military speaking out against the president and oh my GAWD let’s talk about the states of matter.

No doubt nearly everybody knows the three major states of matter, although few people may be aware that there are actually several other states of matter as well. The definitions of the three major states are, in my humble opinion, quite eloquent in their simplicity. Solids have fixed volume and fixed shape. This is important for solids, and why most of our furniture is made out of solids. When we leave the chair in the house to go to grab some lunch, when we return it will still be shaped like a chair. This is a good thing because if it were shaped, say, like a puddle or suddenly ninety percent smaller it probably wouldn’t be terribly useful as a chair any longer.

Liquids have fixed volume but variable shape. If we pour this delicious nutritious not really diet cola I’m drinking from the bottle into a glass, it will assume the shape of the glass as opposed to now when it is bottle shaped. I mean, no hollow, but shaped like the bottle. And the glass had better be large enough to hold the liquid because the volume when I transfer it into the glass will be the same volume (less liquid left coating the surface of the bottle) as in the bottle itself.

Gases have variable volume and variable shape. If I have a gas in a compressed bottle, its shape is bottle shaped. When I use it to fill up my car tire, it expands to fill the volume of the tire, and will assume the shape of the tire as well. Between volume and shape, we can define all three of these states. But, you know, there are others.

Plasma is a fascinating state. Yes, I know, it’s the fluid in which blood cells exist, but it’s also a state. Same name, very different thing. I mean, I’ve donated plasma, but I really can’t donate plasma because I need plasma to live but plasma would kill me. Plasma is a form of gaseous state but at such an extreme temperature that atoms and molecules themselves fall apart and lose electrons. It’s basically a gas of ions and free radicals that are excessively reactive and dangerous. You’ve actually seen plasma, believe it or not, and probably have even created plasma, but you would call it “flame”. It glows because it’s so believably reactive that it’s reacting with oxygen to form light and heat in a self-sustaining cycle.

The glassy state is a semi-stable and fascinating state. It’s kind of hard to explain, but you’re familiar with it. Glasses are caused by “quenching”. Have you noticed that most liquids are clear (but not necessarily colorless which is not the same thing), and most solids are opaque? Glass is made primarily from silicon dioxide, which is sand. The way glass is made starts with melting the sand, making it a clear liquid. The molecules go from an orderly crystalline structure to a liquid. In solids, the molecules are in a regular fixed arrangement; if you know where three of them are, you can find every other molecule in the crystal. In a fluid, the molecules are free to slip and slide over each other randomly, never getting too far but also not held strongly enough for the rigid structure. “Quenching” is the process of rapidly cooling the liquid below the temperature where it should be solid, but without giving it time to rearrange the molecules into the crystalline structure. The viscosity (resistance to flow) of the molecules increase to the point where they basically can no longer move, but they are stuck in the random fluid arrangement. So, it’s a solid, but with a fluid molecular structure.

I can think of a few more states of matter, but let’s talk about just one more; the Bose-Einstein condensate. I’ve written before about how nothing can ever be proven in science, but only disproved. Quantum theory is no different, and so alien to us that many people still don’t believe it. But interestingly, everything that can be predicted with quantum theory has been tested, and has always been proven true, so the evidence is stacking up to support it. Predicted by Albert Einstein and expanded upon by Satyendra Nath Bose, the Bose-Einstein condensate is a quantum state of matter. Two things must be understood to see how this occurs. First, you have to understand that temperature is related to molecular motion. The higher the temperature, the faster molecules move. Secondly, Heisenberg’s Uncertainty Principle tells us that we cannot know momentum and position simultaneously. We can measure one of the two as accurately as we like, but the error in the other increases to compensate for this accuracy. As temperature approaches absolute zero, momentum approaches zero as well (momentum is mass times velocity, so as velocity approaches zero, momentum approaches zero). If the momentum is zero, our knowledge of the momentum increases dramatically, but Heisenberg tells us that because our knowledge of momentum is highly accurate, the position of the atoms cannot be known. As the atoms momentum approach zero, their position expands and overlaps creating a supermolecular state called the “Bose Einstein Condensate”. This occurs at temperatures so close to zero that, experimentally, it could not be created until 1995.

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