- 3065 - TEMPERATURE - absolute zero degrees. Physicists at the National Institute of Standards and Technology in Boulder, Colorado, chill an aluminum membrane to 0.00036 Kelvin, lower than theory predicted possible for the material. The experiment suggests a way to see quantum effects, like a single object coexisting in two places at once
--------------- 3065 - TEMPERATURE - absolute zero degrees
- What we call temperature, or heat, is just an easy way to measure “thermal energy“. Everything in the universe has thermal energy, which exists in the form of vibrations in atoms and molecules.
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- If you add thermal energy to an object, its atoms and molecules vibrate more, and it warms up. If you remove thermal energy, its atoms and molecules vibrate less, and it gets colder.
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- How cold can it get? Start at a nice warm temperature, say 75 degrees Fahrenheit (24 degrees Celsius). You only need to wear a shirt and shorts, and you might even want a cold drink.
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- Except that now, you're starting to feel a little chill in the air. The temperature is dropping to 45 degrees F (7 degrees C). You'd better grab a coat and long pants.
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- A few more minutes, and we're at 32 degrees F (0 degrees C). You need a hat and gloves, and you can see your breath in the air as the water vapor from your lungs condenses in the cold, fogging up your windshield.
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- We reach 0 degrees F (-18 degrees C). Your body is shivering, using muscular energy to generate heat to keep you warm. And your cold drink has frozen solid.
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- We have reached -44 degrees F (-42 degrees C). Time to switch to the Kelvin scale, where it's 231 Kelvin. Regular thermometers don't work anymore because their mercury has frozen solid.
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- You've probably never felt cold like this. You're numb, and your extremities are frostbitten. As the temperature drops further, substances that were once pliable become brittle. Your leather seat begins to crack and crumble under your weight, and a rubber tire wouldn't bounce on the floor, it would shatter.
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- Our next stop is 184 K (-129 degrees F or -89 degrees C), the lowest temperature ever recorded on Earth. Now things really get strange. The air itself starts to condense. First, carbon dioxide condenses, forming tiny frost-like crystals.
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- Then, at around 90 K (-298 degrees F or -183 degrees C), oxygen condenses. Pretty soon, the air that once filled your car is a pool of liquid on the floor. But don't worry about that. You're no longer breathing anyway. Even the warmest parka in the world couldn't save you at this temperature.
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- There is some good news, though. Your car's electric system just improved. Usually, even really conductive materials like copper wire lose energy because of electrical resistance.
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- But at about 133 K (-220 degrees F or -140 degrees C), as vibrating molecules slow down, certain metal-oxide ceramics lose their resistance, becoming superconductive. At even lower temperatures, metals like lead and tin become superconductive, too.
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- Eventually, the inside of your car reaches the temperature of the darkest parts of space, about 3 K (-454 degrees F or -270 degrees C). This is as cold as the universe gets.
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- There is just enough ambient thermal energy bouncing around to keep us from ever shedding those last three degrees. Naturally, at least. In the lab, scientists have managed to drop the temperature below 3 Kelvin down to just a few billionths of a degree above absolute zero (0 K or -460 degrees F).
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----------------- Here is how low temperatures have been in a race to the bottom:
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- Year 1926: Chemists first describe a method, called “adiabatic demagnetization“, that uses magnetic fields to cool materials below 1 kelvin.
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- Year 1933, scientists employ it to chill a salt to 0.25 Kelvin. That’s low, but not as low as laser cooling can go.
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- Year 1978: First demonstration of laser cooling takes materials to 40 Kelvins; 10 years later, physicists use laser cooling to achieve 43 millionths of a Kelvin.
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- Year 1997: Three physicists share the Nobel Prize for inventing laser cooling.
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- Year 2015: Stanford University researchers chill a gas made of rubidium, a soft metal used to make solar cells, to 50 trillionths of a degree above absolute zero, setting a new record.
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- Year 2017: Physicists at the National Institute of Standards and Technology in Boulder, Colorado, chill an aluminum membrane to 0.00036 kelvin, lower than theory predicted possible for the material. The experiment suggests a way to see quantum effects, like a single object coexisting in two places at once.
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--------------------------------- Other Reviews available:
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- 2946 - TEMPERATURE - a race to the bottom? - Scientists are probing the extreme ends of the spectrum of what’s called “absolute temperature“. At the upper limit, absolute hot is a theoretical furnace where the laws of physics melt away. On the flip side, absolute zero is cold, so cold there’s nowhere to go but up. This absolute zero is almost within scientists’ grasp.
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- 2564 - TEMPERATURE - calculating global Warming? How to measure the temperature of stars? Knowing the temperature of the Earth how to calculate the total energy being radiated? We live on the surface of a 2,000,000,000,000,000 one hundred light bulbs. And, the Sun that is warming us has a surface temperature of 6,000 degrees Kelvin. How do we know these things?
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- 2563 TEMPERATURE - Getting Temperature from Light? If we measure the frequency emitted we know the energy gap between orbits for that particular atom. And , if we know the energy gaps for each element we can measure the frequency of radiation and identify the element that created. it. That is how astronomers know the makeup of stars and gas nebulae that are billions of light years away.
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- Review 505 How small is the Atom”
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- Review 983 - “How an Atom Works”
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- Review 985 - “Measuring How an Atom Works“.
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- Review 986 - “How a Molecule Works“.
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- Review 924 - “Rutherford’s Atom”
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- Review 1740 - “Temperature of the Earth”
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- Review 2377 - “Defining the Atom”
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- Review 2333 - “Rainbows can Tell Us What the Universe is Made Of.”
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- Review 2555 - History of the Atom to 1925
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- Review 2555 - History of the atom after 1925
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February 27, 2021 TEMPERATURE - absolute zero degrees 727 3065
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--------------------- --- Saturday, February 27, 2021 ---------------------------
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