engineering, physical experiment, physics, short, silly

Crappy Plastic Bags

Plastic grocery bags suck, and for many reasons. They’re light enough to be carried away by a particularly motivated fruit fly, which means they turn into litter very easily. And since they shred easily into tiny, tiny pieces, they’re probably an excellent source of plastic pollution, which is looking more and more like a major problem every day.

Luckily, the flimsy grocery bags I’m talking about are made of LDPE: low-density polyethylene. And while LDPE isn’t exactly the kind of thing you wanna put on a sandwich, as far as plastics go, it’s relatively mild. Chemically, it’s very similar to wax. Unlike, say PVC and polystyrene, LDPE is a lot less prone to breaking down into scary aromatic and chlorinated hydrocarbons. Plus, it’s not full of the slightly scary plasticizers found in many other plastics.

But my real issue with grocery bags is that they suck. They’re pretty shitty at the one thing they’re made for, which is holding groceries. This morning, on my way to work, I stopped to get some milk. The jug couldn’t’ve weighed more than three or four pounds, but that didn’t stop it from bursting right through the bottom and falling on the floor. I realize I’m making myself sound like a cranky old man when I say this, but I don’t remember plastic bags being quite that fragile when I was younger. And I would’ve noticed if they were, on account of the number of times I tied a grocery bag to a string and tried to fly it like a kite. They didn’t last a long time doing that, but I’d be willing to wager the modern ones would rip before you could get the kite string tied on.

But I’m going to do what crotchety old men never seem to: I’m going to back up my whining with evidence. Here is my evidence.

Crappy Plastic Bag

I’m sorry for the godawful picture, but it gets the point across. What you’re looking at is a pair of lower-mid-range digital calipers, which are pretty handy for measuring things to decent accuracy and precision. The calipers are clamped down around a flat strip of grocery-bag material which has been folded three times, giving eight layers. In the name of fairness, let’s assume that the actual thickness is 0.095 millimeters: just barely thin enough that the calipers didn’t round it up to 0.1. Divide 0.095 by eight, and you get 0.011875 millimeters, or 11.875 microns. For comparison, a human hair is usually quoted in the neighborhood of between 80 and 120 microns. The one I just pulled out of my own scalp (you’re welcome) measured 50 microns. Measuring ten sheets of printer paper and dividing by ten gave me 102 microns. A dust mite turd is apparently between 5 and 20 microns. (Wikipedia says that this book says so, and while I’ll do a lot of things for my readers, I’m not reading a thousand pages to find a passage on dust mite poop.) Human cells usually range between 10 microns and 50 microns (though some get a lot larger).

To get some more perspective, an American football field is 150 yards long and 55 1/3 yards wide. If we were to cover an entire football field with a single layer of grocery bag material, the whole damn thing would only weigh 162.9 pounds (73.9 kilograms). That’s less than me. Less than the average American football player. Hell, that’s less than my dad, and he’s built like a lean twig. Imagining the horrendous suffocation hazard that sheet will pose when it inevitably blows into the stands is making me nervous.

Now, this is only one data point, admittedly. I didn’t measure the thickness of plastic bags when I was a kid (I was too busy making kites out of them, or walking around the house with a mirror pretending I was walking on the ceiling). But that seems excruciatingly thin to me. In order for a soap bubble to be iridescent, it must undergo thin-film interference. This means that, in order to reflect violet light (the shortest wavelength visible to the eye: around 380 nanometers), the bubble can be no thicker than 71 nanometers. My grocery bag is only 167 times thicker than a damned soap bubble. No wonder my groceries fell out this morning, and no wonder every time I go to the hardware store, something pokes a hole in the bag and makes my tools fall out.

biology, physical experiment, science, short, Weird Food

Real Mad Science 2: Mead

Mad Science Mead.png

I used to be pretty fond of booze. My favorite libations were Johnnie Walker Black Label, cheap supermarket Moscato, this horrible fluorescent-blue fruity cognac stuff called Hpnotiq (yes, really), and White Russians. But, towards the end of my college career, I made a nasty error: I got careless with Jägermeister. Jäger, exactly like plutonium or nitroglycerin, is very unforgiving of carelessness. The next day was among the ugliest in my life, and I’ve hardly touched hard liquor since then.

That’s actually a good thing, since it nudged me towards drinking less stomach-scorching things like proper decent wine and beer (and alcoholic ginger beer). And, since I’ve been in a mad science mood lately, I decided I’d take advantage of Amazon’s “Black Friday is happening some time during this month money money money” sale and pick up a little proper brewing equipment.

Several words of warning. 1) Home brewing comes with risks. You could get nasty unwanted yeasts or bacteria or mold that turn your brew toxic. To that end, I sterilized my equipment with a cheap and easy (and slightly nostril-stinging) potassium metabisulfite-citric acid wash. 2) Booze can get you into trouble if you don’t treat it with respect, and it’ll get you into a lot of trouble if you’re under drinking age. 3) Home brewing is illegal some places.

Now that I’ve made it painfully obvious that I’m trying not to get sued, it’s time to make mead! Mead is a fermented honey beverage favorited by Norsemen, English Majors, Beowulf, and pretty much everybody in Skyrim. Here’s how I made it:

I added two cups of honey (about 475 mL) to a saucepan. Because it was a really cold day, I added some water to make the honey less viscous. (Filtered well water, mind you.) To make sure the yeast had vitamins and minerals that pure honey might not provide, I added a generous handful (roughly 1 cup, or 100 – 150 grams) of cranberries, along with a modest handful of raisins. They were just what I had lying around. For flavor, I added about a teaspoon of cinnamon. I brought the whole mixture to a boil. I checked the temperature with an instant-read meat thermometer (never use the proper tool for the job, I always say). Once it reached 212° Fahrenheit (100° Celsiusigrade), I started a ten-minute timer. There are probably nasty unwanted things like weird bacteria, wild yeasts, mold, and microscopic politicians in the fruit and maybe the water and honey, so I figured ten minutes at a boil would heat everything enough to kill them.

Before I started boiling the mixture, I had prepared my brewing gear according to reasonable sanitary standards. Into a 1 gallon (3,750 mL) glass carboy (moonshine jug, as I’m sure many people call them), I added half a gallon (roughly 2,000 mL) of clean filtered well water. To that, I added two teaspoons of powdered potassium metabisulfite and one tablespoon of granulated food-grade citric acid. The reaction produces sulfur dioxide, which kills germs. (Don’t smell the jug while the chemicals are sitting in there: sulfur dioxide really burns the nose…) Just before it was time to pour the fruit-honey-water mixture into the carboy, I gave the carboy and the airlock (which keeps dust and other potential germ-carrying stuff from falling into the carboy during fermenting) a rinse with clean water. I let the boiled mixture cool and then added it slowly to the carboy, which I’d warmed in the oven. I didn’t want to risk temperature differentials shattering the glass. Luckily, there were no problems. I bloomed 2 grams of distiller’s active dry yeast in a cup of warm water with two tablespoons of sugar dissolved in it, then added the bloomed yeast to the carboy. I topped it up almost to the top with clean water, then added the airlock, filled the airlock with water, and gave the jug a gentle shake to get things going.

That was yesterday. Today, when I took the picture, the mead was bubbling merrily away. It’s eating sugar and making things like carbon dioxide and ethanol. The airlock produces a bubble once every five or ten seconds, which tells me the fermentation’s going well. I’m not sure how long you’re supposed to leave mead, but I guess I’ll wait until the bubbling stops, which will tell me I’ve got a bunch of dead yeast drowned in ethanol. I suppose I’ll make the tasting of the mead part of my weird food series…

electronics, physical experiment, real mad science, science, silly

Real Mad Science #1

I like the idea of those little USB power banks. If your phone dies, you can plug it into one, and boom! It’s like you’ve got a whole other battery to run your device off of. Because that is, literally, what you’ve got.

I didn’t have a power bank. I usually don’t need one, since I rarely travel too far from home, on account of the world scares me. But I decided I did want to have a powerbank for emergencies. And since I’ve been doing a bit of soldering lately anyway, I decided why not make my own.

A sensible person would have, say, bought the cheapest possible cordless drill battery and used the cells from that. I am not a sensible person. Here’s my improvised power bank (which I must add, actually works, although I forgot to turn the phone’s screen on for proof):

Ghetto Power Bank.png

That’s what normal DIY techie people do, right? They wire two lantern batteries in parallel, solder the leads to a car cigarette lighter USB charger and plug their phone into that. Right?

These are ridiculously cheap lantern batteries. Probably zinc chloride “heavy duty” cells, which means they’ll probably leak horrible corrosive stuff as they age. But, wonder of wonders, the bastards work. A few dollars, some solder, and some throwing away of common sense, and I have a perfectly functional powerbank. It’s not rechargeable, of course, but I don’t need it to be. This is for, for instance, those times when the power goes out and I can’t charge my phone, but I really wanna keep watching Big Clive videos on YouTube, and I need a charge.

There you have it: the first (and definitely not the last) act of Sublime Curiosity Real Mad Science. I should probably punch up the name.

EDIT: Here’s the powerbank after I neatened it up with a little extra solder, too much hot glue, and a switch, so that the car adapter wouldn’t run all the time and slowly drain the batteries.

Better Ghetto Powerbank.png

EDIT 2: I did a little poking around on the Internet, and found that, in all likelihood, each of these lantern batteries holds 11,000 millamp-hours. Since they’re in series, I’ve just gone and made myself a 11 amp-hour powerbank! From watching too much Big Clive, I know that an iPhone like mine will take 500 millamps if it can, but with these batteries, that’s something like 22 hours of continuous charging. Not bad, for $8 worth of batteries!