Tag Archives: science

It’s time for Einstein’s General Theory of Relativity!

It seems Time and Space aren’t two separate things after all. They’re 2 parts of one thing: TimeSpace. They’re what’s called a continuum.
(kon-TIN-you-uhm)
1 : a coherent whole characterized as a collection, sequence, or progression of values or elements varying by minute degrees
https://www.merriam-webster.com/dictionary/continuum

The Sweet-Salty continuum

I suppose a piano keyboard could be considered a continuum: lowest note on one end and highest note on the other, with the keys in between playing both low and high. You could draw up a continuum of food—from, say, the sweetest food you ever ate to the saltiest food you ever ate. Where is barbecue—both sweet and salty—on your continuum?

The continuum of TimeSpace has extreme ends, too—one end nothing but time and the other end nothing but space. This is really hard to think about. Time passes on one end but nothing physical is there. There’s physical stuff on the other end but nothing moves because it’s outside the medium of time. We live in the middle. We’re physical beings in a physical world who walk around and grow older and have kids and live our lives while plants sprout, bloom and die and the planets and stars whirl around in space.

(Does any of this remind you of Sunday-school? I mean how the Bible starts: “In the beginning…” and then God creates the universe, the Earth and the heavens, separates day from night. It’s how the Bible explains time and space. Which means God exists outside the TimeSpace continuum, which is too much for my brain to handle.)

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Feedback loop

A cesium atom oscillates 9,192,631,770 times every second. That never changes.

What does change is the atoms’ energy state. The excited cesium atoms bounce off the detector every time the microwaves hit the same frequency as the atoms’ oscillations. The detector sends a signal to the microwave resonator, so that the microwave frequency is adjusted to sync better with the atoms. This is called a feedback loop. The detector sends a signal, the signal adjusts the microwave frequency, the microwaves excite the atoms, the atoms bounce off the detector, the detector sends a signal, the signal adjusts the microwave frequency, the microwaves excite the atoms…over and over and over. The time between each signal is exactly one second. No gears, no moving parts to oil, nothing mechanical.

That’s it! That’s how the atomic clock works. Thanks for sticking with me for an entire week on this. Finally, we can get on with our lives!

As with my explanation of the liquid crystal display, this is a simplification. I left out a lot of stuff. It’s the idea, the principle, that I was interested in explaining. Luckily for you, here are links to click on if you’d like more exact, in-depth info about atomic clocks.

https://www.livescience.com/32660-how-does-an-atomic-clock-work.html
https://www.timeanddate.com/time/how-do-atomic-clocks-work.html
https://www.gps.gov/applications/timing/


https://science.howstuffworks.com/question40.htm
https://www.fda.gov/radiation-emitting-products/resources-you-radiation-emitting-products/microwave-oven-radiation
https://science.howstuffworks.com/atomic-clock3.htm
https://www.britannica.com/technology/atomic-clock

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Please continue to hold while I sort this thing out

Remember how mechanical clocks are prone to lose time? It’s because they’re made out of physical machinery—pendulums or mainsprings and gears. We replaced those mechanical parts with a quartz crystal, zapped it with electricity to make it vibrate and got digital clocks. Digital clocks are more reliable, but they still lose 15 seconds every month.

To make the even-more-reliable atomic clock, we replaced the quartz crystal with atoms. Atoms vibrate on their own. We’re building a clock that’s as free of physical, mechanical parts as we can manage in this bad old fallen world.

Here’s what I’m getting from my exhaustive research so far: somehow cesium atoms are funneled down a tube. How do they get the atoms out of the cesium? I don’t know. The atoms are exposed to radiation—radio microwaves like the kind you use to heat up your old cold French fries—which makes them switch back and forth between energy states. The idea is to tune the radio waves to sync up with the atom’s own vibrations at 9,192,631,770 times every second. It’s not easy to get this exactly right—like tuning in a jazz station from 2 counties over on an old radio with dials. There’s a detector at the end of the tube. When the radio waves are at the exact right frequency (the same frequency as the atoms’ vibrations), the atoms change energy states and bounce off the detector—which means one second has passed. Then what? I dunno. How does the detector know when the atoms change from State B back to State A ? I dunno.

Back to my research. Thanks for your patience. Please continue to hold.

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Hail, Cæsium

Here’s something else about atoms: they vibrate, just like a quartz crystal, but you don’t need to zap them with electricity. An atom vibrates on its own at a steady, predictable rate. Incredibly steady, even.

 

cesium

No-see-ums are annoying bugs. Cesium is an element.

Some of the best atoms for vibrating steadily are the ones that make up the element cesium (SEE zee uhm)—that’s Cs on your periodic table. Cesium is kind of rare and its melting point is room temperature. The cesium atom has only one electron circling its nucleus. The cesium atom vibrates 9,192,631,770 times every second.

https://www.livescience.com/37578-cesium.html
Yeah, yeah, we pronounce it SEE zee uhm even though it’s properly spelled caesium or cæsium which means it ought to be pronounced KY zee uhm because the a makes it a hard c but we pronounce cæsar SEE zur instead of KY zar so what are you gonna do. Option-apostrophe for you typography nerds https://www.dictionary.com/browse/caesium

I’m still processing all this info, gang. The atomic clock is still a mystery to me. Thanks for holding.

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Atoms. They’re small.

Here’s something: before I can even begin to figure out how atomic clocks work, it may be helpful to understand what an atom is. An atom is the smallest thing that exists. Anything you can touch is made out of atoms. Lots of ‘em. There is literally nothing physical that’s smaller than an atom.

An atom is made out of subatomic particles, but these can’t be separated so they don’t count as being smaller than a whole atom.* These particles have Greek names (like Aristotle hahajustkidding). In the middle of the atom are neutrons and protons stuck together in a clump, called a nucleus. Around the nucleus are electrons, circling like the moon circles Earth.** The electrons don’t fly away from the nucleus because the neutrons and protons exert a magnetism kind of like gravity.

So, no, I still haven’t figured out how the atomic clock works. This is taking longer than I thought. I’ll be back as soon as have more info. Please continue to hold.

 

https://www.britannica.com/science/atom

*Ms Physics chimes in: “Atomos (Greek) ‘indivisible’ later proved incorrect!” Well, yes, that’s true. I don’t want you kids getting any ideas. Please, if you manage to isolate an atom—DON’T SPLIT IT!

 

 

** Another Western Civ Irregular Jeffrey K takes exception to me comparing an atom’s nucleus to a planet and electrons to orbiting moons. He says “Electrons don’t really orbit like planets– more like moths around a flame (without the usual fatalities). Also electrons are magnetic but the rest is held together by nuclear forces.” I said “So far as I know, nobody’s seen an atom because they’re so teensy.” So he sent me this:

 

https://www.school-for-champions.com/science/atoms_solar_systems.htm#.Xyk9hB17nzI

 

 

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Atomic Clocks

We’re now at the point where we can talk about…atomic clocks, which lose only one second every 100. Million. Years. Yay!

What is an atomic clock and how does it work? That’s an excellent question. Honestly, I have no idea. You would think, as an adult grown-up-type guy, I’d know something like that. I don’t. I avoided science classes in school so I could hang out in the art room.

I don’t know how you get atoms to float around in a tube so you can zap ‘em with radio waves until they change into a different energy state and bounce off a detector that counts the atoms in their new changed state and funnels the whole mess into a feedback loop…

I need to go away for a few days and marinade myself in sciency research until I figure this one out. I’ll be back. In the meantime, please enjoy this hold music—

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32,768 oscillations per second

When you hit a tuning fork against something it vibrates, giving a specific musical note.

We learned that a digital clock is regulated by measuring how many times a quartz crystal oscillates per second—32,768 times. How does it count all those vibrations so quickly? Here’s how: the crystal is purposely cut with a laser to exactly the size and shape (the shape of a tuning fork) that will produce 32,768 oscillations in a second, then stop.* The electric circuit zaps the crystal with electricity, which makes the crystal vibrate until it returns to its original shape. When the vibrating stops, exactly one second has passed. The stopped vibrations trigger the circuit to move the second hand and give the crystal another zap.

The same principle applies in animated entertainment for children. The mouse hits the cat, who oscillates for a second, then resumes his former shape.

Here’s how a tuning fork works: https://www.youtube.com/watch?v=hW-igtIn3A8

Basics of LC oscillators and their measurement


https://en.wikipedia.org/wiki/Crystal_oscillator

* “Because 32768Hz can be so conveniently divided to give a 1 second pulse, it is a very popular size for it to be cut to. Manufacturers can bang them out and be sure they will sell.” https://www.quora.com/Why-does-Quartz-vibrate-exactly-32768-2-15-times-per-second

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The liquid crystal display explained!

Three inventions moved clocks and watches away from being mechanical/analogue so they could become digital: The quartz crystal, the circuit board and the liquid crystal display.

Okay, I sort of explained how a battery works. I kind of explained how a quartz crystal works. The circuit board was easy—even a shmo like me can explain printed metallic ink on a plastic card. But—liquid crystal display? I started this post about 17 times and kept getting lost in the weeds with carrot juice and double melting points and twisted nematics and polarization…

Let’s start here: analogue clocks and watches were inaccurate because they have physical, mechanical moving parts. So we replaced the wound-up mainspring with a battery. We replaced the balance wheel with a vibrating quartz crystal. Now we need to replace the moving mechanical gears, hour-hand and minute-hand with a digital (just the numbers) display of the correct time. How do we do that?

A digital wristwatch made by the Japanese company Casio.

Instead of mechanical gears and hands, we’re going to use electricity and light.

We want a watch-face that will light up and show us what time it is. We want most of the face to light up except the numbers, which should be black so we can read ‘em easily. We’ll block the light in the shape of each number so it shows up black. The numbers will change every minute, so we need a way to change the blocked areas every minute.

In order to block the light, we need a filter. The filter lets us control which rays of light pass through and which rays get blocked. A filter could be a wall of liquid filled with crystals that all face the same direction. The lined-up crystals let the light pass through. We’ll sandwich this wall between 2 plates of glass. The crystals still let light pass through—until we zap them with a little electricity. The electricity upsets the crystals so they don’t line up anymore and light can’t pass through.

We’re only going to zap in certain areas. We want those certain areas to be shaped like numbers. For instance, when we zap the glass in the shape of a ‘3,’ those crystals in the 3-shape get upset and don’t line up with the rest of the crystals in the wall. Light can’t pass through the 3-shape, so we see a black ‘3’ on a lighted watch-face.

Just like on a circuit board, we’ll print the numbers onto the glass in ink. This ink is transparent—and it conducts electricity. Each number is designed as a 7-segment figure, so we can zap only the segments that form a ‘3,’ or whichever number we want. Each segment is wired to the battery.

This is the principle behind LCDs. It’s a simplification. I left out a lot of stuff. But you get the idea, right?


https://electronics.howstuffworks.com/lcd.htm
https://electronics.howstuffworks.com/gadgets/clocks-watches/difference-between-quartz-and-liquid-crystal2.htm
http://www.madehow.com/Volume-1/Liquid-Crystal-Display-LCD.html

Many thanks to a couple of the Western Civ Irregulars, Diana (Ms Physics) and engineering-wiz Don M—both pals of mine since childhood. They pointed me in the right direction when I couldn’t find a way to explain this one.

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Quartz crystal

Three inventions moved clocks and watches away from being mechanical/analogue so they could become digital: The quartz crystal, the circuit board and the liquid crystal display.

Quartz is a common mineral that does this weird thing: it generates a tiny bit of electricity if it’s squeezed, and vibrates when you send an electric charge through it. Watchmakers cut quartz into a shape that looks like a tuning fork, so it vibrates like a tuning fork.

So if we just squeeze the quartz—I’m not sure if this is really the way it happens…

…wow! It works! (photo credit: KTUL.com)

Amazing!! (photo credit: Google Earth)

Okay, okay, that was just a gag. You knew that, right? Just a teeny tiny electrical charge passes through the quartz crystal to regulate the watch.

“Inside a quartz clock or watch, the battery sends electricity to the quartz crystal through an electronic circuit. The quartz crystal oscillates (vibrates back and forth) at a precise frequency: exactly 32,768 times each second. The circuit counts the number of vibrations and uses them to generate regular electric pulses, one per second. These pulses can either power an LCD display (showing the time numerically) or they can drive a small electric motor (a tiny stepping motor, in fact), turning gear wheels that spin the clock’s second, minute, and hour hands.” https://www.explainthatstuff.com/quartzclockwatch.html

https://electronics.howstuffworks.com/gadgets/clocks-watches/digital-clock2.html

A Short History of Digital Clocks and Watches

https://h2g2.com/edited_entry/A1006534

A Brief History of the Wristwatch – Part 1

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The Tropics

Here’s something interesting: the Tropic of Cancer and the Tropic of Capricorn don’t stay put. They move around a little bit. The Tropic of Cancer marks where the Sun will shine the longest in the northern hemisphere for this year—that is, the summer solstice. It’s at around 23-24 degrees north. On the summer solstice, June 21st-ish, the Sun will shine directly over the Tropic of Cancer.

The Tropic of Capricorn marks where the Sun will shine the longest in the southern hemisphere—that is, the winter solstice. It’s at around 23-24 degrees south. On the winter solstice, December 21st-ish, the Sun will shine directly over the Tropic of Capricorn.

tropicsflat

Here’s kind of what they look like on a flat map.

The reason the Sun shines directly on the Tropic of Cancer in summer and the Tropic of Capricorn in winter is that our Earth is tilted as she revolves around the Sun. We learned that way back when we read about Eratosthanes.

It takes one year for Earth to orbit the Sun. When the Northern Hemisphere is tilted toward the Sun it’s Summer there. When the Southern Hemisphere is tilted toward the Sun it’s Summer there.

Latitude and Longitude

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