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5 Delightful Science Experiments From 100 Years Ago

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In 1892, the dubiously named Mr. Tom Tit published a book of at-home activities for children called Magical Experiments: or, Science in Play. He made sure each scientific exploration could double as a parlor trick; something exciting and strange to impress as well as instruct.

Some of his experiments are all but impossible to do today (even if you can find spermaceti candles, you really shouldn't use them), and some of his once common ingredients haven't been available at drug stores for decades. But that doesn't mean you can't do them. If the product still exists, you can find it online. This accessibility re-opens a whole forgotten world of fantastic science fun, one that leaves the tired vinegar and baking soda volcanoes looking hollow.

1. Bottle cannon

You'll need: Empty champagne or wine bottle with cork, baking soda, tartaric acid, a notecard rolled into a tube, thread, wadded paper, two pencils, and thumbtack.

The trick: The original text phrases it better than I ever could:

Would you like to imitate at table the explosion of cannon, listen to the thunder that frightens nervous people, and even observe the actual recoil of your artillery? You may safely answer, "Yes;" for the experiment I now propose is a quite harmless one, as you shall see.

Fill the bottle a third full of water and dissolve "a certain quantity" of baking soda into it. (My guess is, the more soda the bigger the bang, so you may want to start small). Pour the tartaric acid into the rolled up note card (again, amounts aren't specified, so best start small) and plug it with pellets of wadded paper. Tie the roll with a thread that you then pin to the underside of the cork with the thumbtack. Replace the cork. The roll shouldn't touch the water until you've laid the bottle on its side, on top of the pencils. Then, the paper will dissolve, the tartaric acid will meet the baking soda, and BOOM, your bottle blasts forth its cork missile and rolls back upon its gun-carriage (pencils), just like a real cannon.

The science: Baking soda is a base, tartaric acid is, of course, an acid. When the two combine, carbon dioxide gas is quickly created. This gas is much less dense than the powders it came from, and needs more room. Blasting the cork out of the bottle is one of the ways it makes that room.

2. Wet coin, dry hand

You'll need: Bucket or pot of water, small object that will sink, and lycopodium powder.

The trick: First, stomp out anything flammable within a 10-foot radius. Then, submerge any little object, like a ring or coin, in your pot of water. Next, apply a liberal puff of your "magic powder" to the surface of the water. Finally, reach your hand into the water and retrieve the object. When you pull your hand out, the object will be wet, but your hand, even though your audience saw you soak it in a bucket of water, will be completely dry. Huzzah!

The science: It's the miracle of a fat little clubmoss called Lycopodium. I say fat because the spores of this plant, when dried, have an amazingly high fat content. The resulting powder is highly flammable but quickly burns out, which is why it is popular as a flash powder for magicians (and often sold under the name "Dragon's Breath"). But more importantly, all that fat hates water. When you reach slowly through the powder, it forms a waterproof glove around your hand, repelling water molecules and allowing you to stay dry in the process.

3. The punishment of tantalus

You'll need: A strong chair and a small treat, someone strong to "spot" Tantalus.

The trick: Thirsty Tantalus was cursed forever to reach for a pool of water that dried up as soon as his hands came near. Here Tantalus just has to pick a taffy up only using his mouth, while not falling off a dining room chair that's been placed on its front legs. Unless Tantalus figures out how to maintain his center of balance, the chair will begin to tip (hopefully into the arms or sofa cushions waiting to catch such an unbalanced snacker).

The science: There is no more fun way to learn about physics than through candy and improper use of mother's good chairs. In this experiment, we use those tactics to explore center of mass. You and the chair each have your own, but you're also sharing one. When you put weight toward the candy, you defy your joint center of balance and the chair responds to the insult by throwing you off. However, if you crouch low (the lower the center of mass, the easier it is to balance) and give as much weight as possible to the heavier end of the chair, you can maintain your center of gravity and retrieve the candy.

4. Magic salad dressing

You'll need: Oil and vinegar, a sealable clear container, and a dinner party

The trick: This experiment is described in the form of a story about a "jolly company" on a picnic together. This company is distraught to see that the man responsible for bringing the oil and vinegar salad dressing saved himself the trouble of carrying two bottles by mixing them together. Not everyone likes the same proportions of oil and vinegar on their salads, after all. So they are astonished when the young men walks around the picnic, distributing both the oil and vinegar, from the same bottle, in the exact proportions requested by each diner. How does he manage it?

The science: We know that a lot of liquids mixed with oil immediately separate. This is because the lipids in oil don't like water molecules, but they love their fellow fat molecules. Vinegar is mostly water, so the two liquids naturally separate when allowed to settle. The oil floats to the top of a bottle and is easily poured out. When the vessel is slowly turned upside down, both components stay put, so the vinegar is now right near the mouth. So, for oil, just tilt the bottle and pour very slowly. For the vinegar, turn the bottle upside down and open the mouth just a little.

5. Automatic drinking fountain for pets

You'll need: A bottle (plastic is fine) that you can affix upside down to or against a wall (it must be removable). A shallow pan and water.

The trick: Technically this device was meant to water barnyard fowl, but it should work just as well for any small animal. The device isn't so much a trick as it is a clever solution to what must have been a common problem: disgusting water-troughs for outdoor animals. The bottle is set up so that the mouth does not quite touch the bottom of the pan, but goes halfway below the brim. The pan will fill with water, but only to the level of the water inside the up-turned bottle mouth. Every time a significant amount of water is drunk, or even evaporated, fresh water comes forth to replace it.

The science: Atmospheric pressure! Water is only able to flow out of the bottle because the bottle is simultaneously sucking in air, trying to match the air pressure of the air outside. But once the water level of the pan rises to the same level as the water in the upturned bottle, the mouth of the bottle is sealed. No more air can enter the bottle to displace the water. At least not until enough water is drunk.

All images courtesy Google Books: Magical Experiments: Or, Science in Play**

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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Here's How to Change Your Name on Facebook
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Whether you want to change your legal name, adopt a new nickname, or simply reinvent your online persona, it's helpful to know the process of resetting your name on Facebook. The social media site isn't a fan of fake accounts, and as a result changing your name is a little more complicated than updating your profile picture or relationship status. Luckily, Daily Dot laid out the steps.

Start by going to the blue bar at the top of the page in desktop view and clicking the down arrow to the far right. From here, go to Settings. This should take you to the General Account Settings page. Find your name as it appears on your profile and click the Edit link to the right of it. Now, you can input your preferred first and last name, and if you’d like, your middle name.

The steps are similar in Facebook mobile. To find Settings, tap the More option in the bottom right corner. Go to Account Settings, then General, then hit your name to change it.

Whatever you type should adhere to Facebook's guidelines, which prohibit symbols, numbers, unusual capitalization, and honorifics like Mr., Ms., and Dr. Before landing on a name, make sure you’re ready to commit to it: Facebook won’t let you update it again for 60 days. If you aren’t happy with these restrictions, adding a secondary name or a name pronunciation might better suit your needs. You can do this by going to the Details About You heading under the About page of your profile.

[h/t Daily Dot]

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