This is why I have a nerd rant in my back pocket all the time about those gigantic whiskey ice cubes. They're sold as cooling your whiskey without diluting it, and that's kind of true in that it dilutes it more slowly, but by diluting it more slowly it also cools it more slowly, meaning the whiskey is warmer while you're drinking it. On top of that many whiskey experts suggest a splash of water in your whiskey to begin with.

The important thing here is that the heat of enthalpy of water/ice is huge compared to the heat capacity of either liquid water or ice. Ice cools by melting!

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Spacetime is the trampoline. The universe is the trampoline. All you do is move through it like you would move over a trampoline.

After the extinction period is over, a lot of unfilled niche means an possible explosion of new species, but not during the extinction period.

I think that the translation from 2 to 3 dimensions is what gets me. The trampoline example makes sense. But when I try to go 3D, I can only imagine it like a pool, where I'm displacing something else. But another response said that matter doesn't displace spacetime. And you said that a dot on the grid isn't separate from the grid.

I spacetime more like a magnetic field? Defining contours and routes, as well as permeating things that are in its influence?

The usual example is like standing on a trampoline or something. You put a dent right under your feet. The further away from you on the trampoline, the flatter the surface becomes. It's pretty much the same but in 3 dimensions instead of 2. You do warp spacetime but you're _very_ small and not very dense so you don't cause any amount of warping that matters.

>If you had an x/y plane and put a point on it. That point is not separate from the grid.

This is part of what I'm struggling with. I'm a mass. If it's just me and spacetime, I'm warping spacetime... around me?

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Forgetting the naturally slower and longer time to cool with a cube in which room temperature would assist in its attempt to cool it down resulting in different temps.

At least I believe a cube sitting in the same temp room as the shaved ice would not be the same temp as the room temperature would take it’s time on heat loss too whilst it sits the prolonged period whereas after the shaved ice melts you take a bite compared to a ice cube and taking a bite after it melts. I dunno.

As many people noted, we either outcompeted, killed off, or interbred with other members of the homo genus. Even if we hadn’t, Homo sapiens travel all I’ve the world every day. We have permanent settlements in all but the harshest environments. If other members of the homo genus had survived, we would have encountered them, and either fought or bred with them. Every other multi-species genus can’t travel the world at the merest whim. Fish, marine mammals, birds, and even butterflies are capable of making tremendous journeys all over the world, but they largely have to follow food sources and/or migratory patterns, which could prevent them from encountering closely-related animals. There is very little choice in where they go.

>Ions are able to pass the membrane freely because of their size and chemical properties your teacher discussed.

Oh no. Apart from a small amount of leakage, ions definitely do not freely cross the membrane. Having control over when and how ions cross membranes is critical to life, not just by enabling neuronal signaling in animals but in being harnessed for ATP synthesis across all domains of life.

Thank you all for your answers.

I have found this in a textbook, "fundamentals of biochemistry", Voet et al., 2016 :

"When a solution is separated from pure water by a semipermeable membrane that permits the passage of water molecules but not solutes, water moves into the solution due to its tendency to equalize its concentration on both sides of the membrane. Osmosis is the net movement of solvent across the membrane from a region of high concentration (here, pure water) to a region of relatively low concentration (water containing dissolved solute). The osmotic pressure of a solution is the pressure that must be applied to the solution to equalize the flow of water across the membrane in both directions."

So, I do not want to split hairs, but I gather (yet I might off course be totally wrong) that the "circulation" of ions following their concentration gradient is simply the net movement which tends to equilibrate the concentration gradients on both sides of the membrane, not because "a force" is acting on the particles, but simply because more particles go from A to B than from B to A.

What do you think about it ?

Others have mentioned that the teacher is correct, and that "chemical force" is an actual term to describe physical properties of things. I just wanted to touch on the subject of membranes in cells. Substances can enter our cells either through active or passive means. Ions diffusing by osmosis is a form of passive transport, which means no energy in the form of ATP is required for transport. Ions are able to pass the membrane freely because of their size and chemical properties your teacher discussed. Larger molecules, such as lipids or proteins, require active transport methods that use special proteins in the membrane that use up ATP.

This is why our nerves work so quickly, the cascading signal of ions happens almost instantly! It is a chain of differing electrical potentials caused by ion gradients.

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Thanks for that very thorough answer. I got thirsty just reading it.

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Assuming that everything else is the same (ice is same temperature in both cases, not considering the effects of the surrounding area, the thermal properties of the bowl, etc.), they would cool it the same amount, though the shaved pieces would melt faster, cooling it faster. However, the soup would likely be cooler after the ice cube melted, than the soup after the shaved pieces melted, because more time would pass by then, so the soup would lose more heat to the surrounding area, to the air and through the bowl over that greater period of time. But that is including the effects of heat radiating into and out of the bowl and directly into the air over that greater period of time, and is not just a change in temperature from the ice cube.

This is slightly ambiguously worded, so I will address the wording in answering the question.

There are two ways to read what you're asking depending on how you interpret "cooling more". Normally, people would use cooling "more" to describe a lower equilibrium temperature (more change in temperature units regardless of time), and cooling "faster" to denote a greater rate of cooling (more change in temp per unit of time)

1. "What are the relationship between *rates of cooling* of shaved and block ice with an identical mass and temperature?"
2. "What are the equilibrium temperatures of the soup + shaved ice system and the soup + block ice system?"

The answer to question 1 is that the rate of cooling of the shaved ice will be greater than that of the block ice. This is due to the greater surface area of the shaved ice leading to more interactions per time. These interactions dictate the cooling effect on the soup, so more -> faster cooling rate.

To answer question 2, if the two samples of ice are identical mass and temperature (and composition), they will both have the same "heat capacity" and the total amount of cooling they both provide will be the same. Even though the block ice will take longer, when it finally finishes the soup will be the same temperature as that with the shaved ice added.

That simulated image is quite cool, but can you imagine what a night sky like that would have done to world religions?

Just to add a bit of detail to the correct answers already posted:

1. Yes, chemical force is a valid concept. See chemical potential in Wikipedia.

2. Osmotic pressure does not have to involve circulation of solvent, any more than air pressure has to involve flow of air.

3. The explanations are correct. They are not even a simplification.

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