Tag Archives: science

The Chinese invent the compass

A thin piece of magnetized iron in the shape of a fish (or a shallow boat) floats in water and points north.

The magnetic compass was invented in China sometime between the 2nd century bc and ad 1st century. They used it to make sure streets and houses aligned with the Earth in a harmonious way—what is called feng shui. The Chinese later figured out they could use a compass for finding their way on the ocean (ad 1040-44).

This carefully-balanced magnetized iron spoon points north with its handle.

How you can harness the awesome and terrible forces of the Earth’s core

We learned last post that the Earth’s core is surrounded by molten metal, which exerts a magnetic field around the planet. Some metals can be magnetized. They can be made into a magnet, so they exert a force on other metals without touching them. Iron and steel can be magnetized.

The thing about Earth’s giant magnetic field is that magnetized metals—if they can—try to line up with it. If you were to take a small piece of iron or steel (like a needle) and rub it a few times with a magnet, it will try to align itself with Earth’s North and South. You could make it easier for the needle if you float it on a piece of styrofoam or cork in a bowl of water. After the needle settles down it will point North-South. Congratulations! You built a compass.

Here’s what you’ll need: a bowl, water, a needle, a piece of cork or styrofoam, and a magnet. I got my magnet off of the refrigerator door. If you cut a slice off the cork, get someone to do it with a craft knife. Use a cutting board! Don’t cut it on your mom’s good dining room table. I don’t want angry messages in the comments section.

Rub the needle with the magnet a bunch of times.

Stick the needle halfway through the cork. It may be a good idea to put the butt-end of the needle on a cutting board and press the cork down onto it.

Fill the bowl with water and float the needle and cork in the water. After a little while the needle will point north-south.

https://www.wikihow.com/Make-a-Compass

https://www.siyavula.com/read/science/grade-10/classification-of-matter/02-classification-of-matter-08

Back to the beginning of The Western Civ User’s Guide to Time & Space

Magnetic fields

Well, everybody who reads this blog called me this morning in a panic because of that last post. The post where I explained how we’re all doomed. I went to bed before going on to explain that we’re not doomed. Sorry, gang.

Probably I should have mentioned: the molten metal inside the Earth is magnetic. It behaves like a giant magnet. Magnets have 2 poles and so does Earth, thanks to its sizzlin’ hot molten metal core. If you’ve ever put a magnet on a sheet of paper and sprinkled metal filings onto it, you’ve seen the filings arrange themselves into circular patterns around both poles. These are magnetic fields.

There are gigantic magnetic fields around Earth’s north and south poles that extend way out into space. You can’t see them. You know what they do? They act like a shield against whatever dust the Sun keeps shooting at us. That’s why we’re not gasping for oxygen and wiping sun-dust off our computer screens.

Pretty neat, eh?

What is Earth’s Magnetic Field?


https://www.khanacademy.org/science/physics/magnetic-forces-and-magnetic-fields/magnetic-field-current-carrying-wire/a/what-are-magnetic-fields

I add this link in the interests of science:
https://www.amazon.com/PlayMonster-Magnetic-Personalities-Original-Wooly/dp/B00BT92SB0

We’re doomed!

Here’s something you ought to know about living on planet Earth. We’re standing on a giant globe that rotates on its own axis, and also rotates around the Sun. Right where you’re standing, deep below the surface you’re standing on, it is hot enough inside the Earth to melt metal! In fact, there’s molten metal sloshing around in there RIGHT NOW! Molten metal!

While that’s going on, our pal the Sun is shooting dust at us. Yes, that’s right—solar winds are blowing enough dust to scrape the atmosphere right off Earth’s surface like sandpaper taking the skin off an apple—RIGHT NOW! No air!

I haven’t been able to sleep a wink since I found out about all this. We’re doomed!

Egyptian sundials

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An Egyptian lady catching some rays from Ra.

Let’s travel west from Sumer, away from the MidEast, along the northern coast of Africa to Egypt. About 1,000 years after civilization was up and running in the Tigris-Euphrates valley, the Egyptians got started on their civilization which thrived from 3100 bc to 332 bc. Like the Sumerians, Egyptians depended on a river—the Nile—and a system of irrigation to water their crops to keep the economy going. Their writing system was hieroglyphics—symbols that represented sounds, or ideas, or things. Their government was monarchical—they had a single ruler, called a Pharaoh. The Egyptians worshiped a pantheon—which means a bunch of gods and demi-gods. The Pharaoh was worshiped as a god, too.

The Sumerian culture must have influenced the Egyptians somewhat. The Egyptians divided the day into two halves, each having 12 hours—twelve is an easy Base Sixty number. The Egyptians are thought to have invented the sundial. The earliest example of a sundial has 12 hours marked using lines on a semi-circle, 15° apart.

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A fragment of a limestone sundial. The gnomon goes into the hole at top.

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This sundial is a half-bowl cut out of a block of stone.

A sundial is a simple way to measure the passage of the Sun. There’s a post (called a gnomon, pronouced NOM-ON) sticking up from a flat, horizontal surface. Lines are drawn on the flat surface, radiating out from the gnomon. When the Sun is shining, the gnomon casts a shadow on the lines. Each line represents the passage of an hour.

The Egyptians built huge obelisks—big stone monuments. These were sundials, too. The obelisk cast a shadow on the ground, which was marked for every hour. As the Sun moved across the sky, the shadow would move along the dial, showing the time. Of course, sundials only work when there’s daylight. How did they tell time at night?

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What is a ‘civilization?’

Okay, gang—before we get started talking about Western Civilization, we should agree on what a ‘civilization’ is. I’m going to keep this kind of loose. Generally, a civilization is a big group of people—in cities, a country, or countries—who share government (a system of keeping law & order and protecting its people);

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a religion (belief in a god or gods with a set of rituals and priests to perform them);

religion

 

 

 

 

 

 

 

an economy (enough food for everyone plus some left over for trading);

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a written language (symbols to communicate without speaking);

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and art, science and technology (inventions that make life easier and more enjoyable).

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Every civilization has a ‘culture’—its own way of living and doing things.

That’s it. A rough definition to understand what separates a civilization from simply a big group of people. Now we can start thinking about what Western Civilization is.

Time to get serious

I’ve sorta-kinda joked on this blog about saving Western Civilization. Even my motto reads: “Saving Western Civilization through kid’s book illustration.” And I’ve honestly meant to get started on that. I have, in a modest way, been promoting Western Civ by teaching Sunday School and posting some historical stuff here once in a while. I haven’t been very serious about that motto, though. But it’s a new year; a good time to get serious.

Why does Western Civ need saving, anyway? We have Shakespeare and quantum physics and cell phones. We have crop rotation and the alphabet and Broadway. That’s good, right? Why can’t I just be happy?

The problem is: I meet very few people who understand how we got Western Civ. There are too many people who think Western Civilization is not such a good thing, and is maybe an embarrassment, or should be apologized for. That way of thinking saddens me, if only because it’s so easy to point to how much human beings have benefited from Western Civilization.

I think it’s important to understand how we’ve achieved all the things that we have. It’s important to recognize our incredible inheritance—gifts we’ve been given by amazing people who are long gone. Why were moveable type or symphonies or Greenwich Mean Time invented in the West? It’s vital for young people to understand how Western Civilization works, so that they may prosper in it.

This is my mission. If I can’t save Western Civ, at least I can document her glories. I like history, so I’m going to be writing a history of Western Civ—particularly a history of ideas. I’ll post the stuff I’m writing here on this blog, as a way of test-marketing. My goal is to write and illustrate a book that presents the history of Western Civ in a fun format. You must know by now that I’m a smart-alec, so of course it will be funny. Lots of gags. Lots of pictures. I expect to learn and discover new info as I do the research.

I invite you all to come with me.

John