Wednesday, September 16, 2015

Sun is NOT the Center of Solar System: A Lesson in Elliptical Orbits



The Sun is NOT the Center of Solar System: A Lesson in Elliptical Orbits




We are going to cover elliptical orbits, ellipses, creating ellipses, sine and cosines, and Johannes Kepler's Second Law of Planetary Motion with an ultra-simple, easy to understand method using a piece of string! 

Kepler was trying to prove that planets sweep out equal areas in equal time periods...except he kept getting errors as he attempted to calculate the orbit of Mars. He tried fitting his calculations to a circle shaped orbit and an egg shaped orbit: no luck. Then he tried an ellipse, succeeded and also proved the sun wasn't at the center of the planets' orbits!

Our sun is not the center of the universe. It is not the center of our solar system. The sun is at one of the two foci of an ellipse, the other focus is an empty area of space. The foci are like two centers of two circles joined together into a blob. BUT THE orbits are so close to circular looking that diagrams of our solar system are basically circles within circles with our Sun at the center (but technically a smidge off). It's called the "barycenter".

In fact you can create a circle by bringing the two foci together-and we'll do that after learning how to easily create ellipses with a piece of string, a compass and two pins. This piece of string will also easily show us Kepler's law of planetary motion: something that is an absolute mathematical truth...but looks totally untrue to human eyes.


Let's start by marking the length and width of the ellipse we want:



Put a pin at each end of the length and connect with a string:



Set the compass to the distance from the center to a length end point:




With the compass set to the distance from the center to an end point of the length, put the sharp part onto a width point and draw marks where the compass-swing hits the line of the length.



Take your pins and string and stick them into the compass marks.




Take pencil and draw while keeping the string pulled tight. There is your awesome new ellipse! You'll notice that the string forms a triangle, kind of like the sine/cosine triangle in the circle from a few posts ago about Lissajous Figures. We'll come back to this triangle in a moment, but first let's Reverse engineer this ellipse into a circle.



As we move the two foci closer and closer together the pencil and string triangle sweeps out a shape that is more and more circular. Put the pins in the same hole (or just use one pin) you'll get a perfect circle.



Back to the triangle sweeping:


Kepler's Second Law of Planetary Motion says that as a planet sweeps along its orbit, in different parts of the ellipse (even the smaller ends) the area it sweeps out is always equal to any other area it sweeps out given the same time to sweep. Two seconds of sweeping in the little end gives the same area as two seconds of sweeping the bloated middle.

That sounds and looks wrong, even in fancy computer animations...but just remember our string triangle: it moves all about and changes angles as it's dragged by the pencil but its overall length never changes. The string doesn't get shorter or longer. The base of the triangle never changes as long as the pins don't fall out. The length of the two other sides of the triangle always add up to the length of the string.

Sameness.

Couple the sweeping in an ellipse with the sine/cosine triangles...


...and add a few more little trigonometry bits like tan and arctan and you get the field of calculating xy ballistics trajectories for non-powered projectiles (bullets, rocks in a catapult, etc.).



Wait, I can use a piece of string to calculate the path of birds?!?



 They'll be non-powered once I gnaw their wings off.

Monday, August 31, 2015

Great Balls of Carbon!

Great Balls of Carbon!






 ...ok, they're actually teeny-tiny charcoal spheres.



These are little black balls I found inside of an old hard drive I just took apart. They are charcoal. Activated charcoal pellets to be exact. Like tiny versions of the charcoal briquettes you might use in your barbeque grill, which were invented by Henry Ford.

You burn something with carbon in it (most things in the universe) while providing lots of oxygen. The result is very porous charcoal. The pores are shallow like the dimples on a golf ball. They increase the surface area and help soak up poisons and other contaminants like gases in the air.

In hard drives they're in a little cup with a vent on one side and gauze on the other. This acts as an air filter for the hard drive. I had the same setup for my aquarium when I raised pufferfish! A gauze pouch with charcoal pellets for cleaning the water.

SiliCON vs SiliCONE  vs Carbon

The carbon pellets are also super bouncy. Like, oddly bouncy. Way more than the polymer ball we made a few posts back. That surprised my, but a quick glance at the Periodic Table shows that carbon lives right above silicon, which you'll remember from the non-Newtonian fluid and polymer post and the fast that it's what makes Silly Putty so bouncy...well, that's silicone with an "e" at the end polymer made from silicon. Carbon forms much more stable bonds than silicon, but it likes other carbons to bind to. Silicon likes oxygen, and although it's less stable than carbon bonds silicon plenty of molecules-great molecular subunits linked together (very bouncy). Silicone rubber (which is a silicon polymer) has a Young's Modulus of 0.001 and carbon is less elastic at 4.1.



Balls bounce one way, balls bounce the other way. Meow. 



Here is one on the xyz stage of my microscope. The white disk is actually the other side of the black cup/filter assembly it was in with a zillion of its pals. A little ways below I have a better photo of this cup.



Here's some various videos made with 3 different cameras, a very nice microscope and some really terrible out-of-sync lighting. This gives a good sense of their miniscule size.



The very same from my previous video:  little black balls I found inside of a hard drive I just took apart.

They are charcoal. Activated charcoal pellets to be exact. Like tiny versions of the charcoal briquettes you might use in your barbecue grill, which were invented by Henry Ford.



They're in a little cup with a vent on one side and gauze on the other. This acts as an air filter for the hard drive. I had the same setup for my aquarium when I used to  raise Figure-Eight pufferfish!

In this video I put them under a very nice microscope...but with a very cheap ($1.99 used) webcam and terrible side lighting. My microscope has very, very, very good lighting for looking at slides and other things properly prepared for microscopy with the light coming from *underneath* the slide-not from the side.

Also a point of annoyance: I was testing a crappy webcam (an ancient GE model) that I bought used for $1.99. The flicker is from the LED flashlight not syncing with the webcam.

So, a lot of ugliness on this one. Check my other videos for better cameras (a big Canon in HD, but also my cheap Samsung cellphone and Nexus tablet have way, way, way better video than this GE webcam).

This video was: cheap camera, cheap flashlight just as a quick peak. On the blog post I'll put some better looking still photos.

For a $1.99 I finally have a webcam. At some point I might bash the lens off of it and point its CCD array straight into a dark container with a photo-amplifier tube / scintillator in it to create an alpha particle radiation detector. Sort of like the alpha spark detector I made a video of, only digital.

The microscope is actually very nice (stereo eyepiece, xyz stage, abby condensor, LED with electronic dimming switch and various mechanical shutters for dimming and changing the incidence angle of the light, 2000x oil immersion lens: basically all the bells and whistles and the highest reflected normal light magnification physics allows! All coupled (today only) on a webcam that costs less than a can of Red Bull, lol.

I was also holding the webcam with one hand while moving the xyz stage and focusing with the other--I'm being terribly unprofessional today. I actually have a side illuminator for microscopes that I could have used also. It has a nice (non-harsh, non-flickering light) but this was only a test and with the lousy webcam it would't have made much of a difference.


I kept changing video cameras, but kept the lousy lighting.




Speaking of old technology, I also found this cool brochure for coin operated computers for our library. Pineapple Computers!





Neat, but my computer glows in the dark!





I don't care about the black balls, but I need you to make sure none of these old hard drives have any snakes in them! Mee-yow!

Friday, August 28, 2015

Aluminum Screams: A Saltwater Synthesizer



Aluminum Screams: A Saltwater Synthesizer


If you touch copper wires to a drop of saltwater on aluminum you can hear decaying and regenerating synthesizer-like sounds! I stole this idea from Nyle Steiner, who I gained tons of information about thermocouples from for the last post. Mr. Steiner is the inventor of a variety of Electronic Wind Instruments and has played on a ton of TV and movie soundtracks-good movies too, like Apocalypse Now!

So, what do you do to make the aluminum scream like the metal coins did in dry ice a few posts back? I did this:

Run two copper wires to a speaker or guitar amplifier.

Join the wires together with a resistor of at least 100k value.

Touch one wire to the aluminum.

Touch either the insulation of the second wire to the aluminum with a little saltwater on it OR carefully touch the copper part of the second wire to a droplet of saltwater on the aluminum WITHOUT touching the aluminum.





You can just attach the wires to the end of a guitar cord, the other end of the cord is of course plugged into a guitar amplifier.




Soda cans are made of aluminum.



Both wires are bridged together with a resistor. Use one that's 100k or more. I tried a few different values and heard no difference, but I didn't try many put out and I had them parallel, not in series.


It seems that I got more complex sounds when touching the wire, or just the rubber insulation to corroded or damaged parts of the aluminum.




Here's a taste of the weirdness in video/audio:


...do you still hear the aluminum screaming Clarice? 

So, what's going on? Well, if you hook up a multimeter you'll find aluminum plus saltwater produces voltage. The voltage is variable. So this may be like a keyboard synthesizer Voltage Control Oscillator (VCO). Saltwater on aluminum foil can be used to create an ultra simple electrolytic battery that can power an LED. Changing voltages makes noises, whether it's steel guitar strings affecting the magnetic field of the guitar's pickup, a microphone diaphragm moving because of human voice sound waves or this crazy setup.

To juice up the electrolytic aluminum and Saltwater battery you can add lye. What would that do to the sound output of our saltwater synthesizer?

Would solid core copper wire sound different? How about different concentrations of saltwater? Burned aluminum? Aluminum that's being heated or even red hot? How about lemon juice instead of saltwater?

This is a great thing to have on the shelf for future experimentation when nothing else is going on. It's simple and easy to change variables in this little circuit.

By playing around you can obtain incredibly complex noises that evolve and sound like Electronic Music. It's really, really weird.




"Build stuff-you'll have fun!" -Michael Logusz


Abstract music, abstract kitty! Meow.

Friday, August 21, 2015

The Power of Cold (and Hot) II: Thermoelectric Generator


The Power of Cold (and Hot) II: Thermoelectric Generator


A few posts ago (The Power of Cold and Hot) we looked at a Stirling Engine, which converted temperature differences into pressure and fast movement.

Now we are going to make a thermoelectric generator (and a thermosistor).


A thermoelectric generator converts temperature differences into electric voltage.

Two copper wires heated until they are crusted with cuprous and cupric oxide.

When touching, the wires are pressure sensitive and heat sensitive where they meet (pressure and heat at the junction cause Ohm resistance to drop). This is a thermosistor: resistance varies with temperature.

Heating only one wire causes Voltage to be produced. This is a thermoelectric generator / thermocouple. With only a butane barbeque lighter I can produce a consistent -5.2 mV (millivolt) when I apply ice to the other wire.

The weird thing is that the eV (electron Volt) work function is 5.2-5.6eV for cupric oxide and 4.8-4.9eV for cuprous oxide. Coincidence? Yeah, probaby...


Store bought thermocouples for home appliances produce 25-30 mV with 30mV being the norm.

I've looked at the work of Nyle Steiner who is a real whiz in many areas of electronics. Here's how I built my version:


Copper wire of equal lengths.




Wood disk and mounting screws.



Heating with a propane torch. It's hard to see here but the blue flame of the torch turns green after passing the copper wires.



Below you can see the scale left after heating. Red is Cu2O which is cuprous oxide (Copper I). Black is CuO which is the cupric oxide (Copper II). These oxides are used in semiconductors.


With two copper wires the hot wire output is negative voltage and the cooler wire is positive.  Nyle Steiner hooked 16 of these wires together and heated them. The result was enough voltage to light up and LED! 

Simple thermocouples like this are used to measure temperature in appliances: different voltages equal different temperatures. This is because temperature gradients produce an electromotive force (emf).

Here's a picture of my new Pyrometer (like a thermometer but for surface temperature). It can read up to 800° F and takes no batteries since the operating voltage comes from the physics we're discussing in this post.



Thermometers measure temperature. Pyrometers measure surface temperature. My pyrometer has a blunt tip for placing near the exterior surfaces of things that are very, very hot. Most thermometers are pointy for jabbing into things for interior readings: into a roasting Thanksgiving turkey, into container of boiling liquid, into your mouth, etc.

Newer pyrometers use infrared, lasery thingies that can tell you if the outside of your turkey is too hot from the other side of the kitchen! Here's a photo of mine:



Of course that's pretty useless since you want to measure the inside of the turkey. The problem is that thermometers need to touch what they're measuring, which is fine for normal things but not great touching something that is 800° F or way hotter like smelting metal! Because they don't have to make physical contact you can use a pyrometer to measure the temperature of a moving object, like a stream turbine.

Nowadays pyrometers also have probes for jabbing into things, so the lines are blurring even more. Thermometers generally are more delicate, require contact and can't handle high temperatures.

These sunny-side-up-eggs are starting to burn!



My pyrometer above is made by West Instruments, another company that makes this sort of thing is Borg. Yes, the same Borg from Star Track, or was is Star War? Anyway, BorgWarnet makes stuff for kitchen ovens, which is where I got the circuit board below, although the sensing portions and timer were probably made by Diehl. I think they're the same Borg that makes turbochargers for Detroit Diesel up the street.


...anyway, back to metal thermocouples:

With wires of two different materials, copper and steel for example, you create a closed loop thermocouple that is very similar to our Sterling Engine...but with electromagnetic waves!

All you have to do is solder the two ends of the copper and steel wire together. Then apply heat to one of the solder joints. The greater the temperature differential-the more mV it will produce. Since it's a closed loop of (two) wire there are no "ends" for positive or negative multimeter attachment so it's easiest to use a compass needle to observe electric (and thus magnetic) production. 

This is how Seebeck Effect devices such as this, Peltier Cooling Modules and Stirling engines can be used to produce electricity-some improvised units can make enough to charge a cellphone!

Like most things electromagnetic, you can use the output (voltage) and get the input (heat) just by reversing things. Running electricity through a shorted wire produces heat. This is called ohmic heating / Joule heating. It's why short circuits get hot, but it's also how a toaster works, and hot wire saws for sculpting sheets of foam for car seats. 


EMF: electromotive feline. The moving clouds and warm sun make me move back and forth. Meow!

Monday, August 10, 2015

Ohm the Capacity!




Ohm the Capacity!


...actually, capacitance is measured in farads. Ohms are a unit of resistance.

Here is my Heathkit decade resistance box. Each knob varies the amount of resistance by units of one, ten, hundred, thousands or ten thousand of Ohms, thus the "decade" part of the name. Heath was a Michigan-based company that provided kits to make clocks, tube amplifiers, test and radio equipment, etc. This decade box is huge, at over a foot long and had a nice wood enclosure.



I bought this box at the Disabled American Vets (DAV) resale shop by my house for two dollars! It was already assembled. I knew it dealt with ohms, but I thought it might be for stereo speaker setup or something. Speakers commonly refer to ohms in their specifications. It just looked cool.

I like the idea of having a zillion resistors of different values in a convenient box. Did they have things like this for other circuit board components? Yep, I found a nice kit to solder of a bunch of capacitors. Instead of resistance in ohms, this deals with capacitance in farads.

Here are some brief photos of the assembly, which consisted of plunking in a small pile of capacitors:




I left the leads of each capacitor really long...they don't look like much, but capacitors store energy, so if you touch this board you'll get a nice sizzling feeling. A bunch of posts ago (So You Wanna See Atomic Particles With Your Own Eyes Huh, Part 3) we dealt with larger capacitors and their deadly potential.





So nice and small. If can toggle between picofarads and microfarads.




As I stated in my previous post, only one of my new multimeters can measure capacitance.


Now instead of swapping circuits in and out by soldering I can just dial up different values of resistance or capacitance for testing.

Insulation

There is no such thing as a perfect insulator. If you hit any insulator with a high enough electrical charge, it will absolutely conduct electricity. Insulators have less ability to let their internal electrical charges move, thus limiting their ability to conduct electricity. Again, there is no such thing as a perfect insulator. Glass comes pretty close.

Way less resistive of an insulator is plastic, but it's good enough to insulate most electrical wiring. Think back to when we talked about transformers: the first coil never physically touches the second, electromechanical waves transfer electricity from one to the other. If you put high voltage through regular wires you can sometimes see glowing auras on the outsides of the wires. Not good!

But what are we gonna do, use glass as an insulator? Yes! Here is some of my utility (telephone) pole insulator collection. They're made of glass and the brown ones are ceramic.











Most of the glass insulators in my collection were made by HemingRay between 1848 to 1972. HemingRay was the world's biggest insulator manufacturer. The brown porcelain ceramic are by SBT and a couple are marked "Slater" which may refer to a couple different companies. The SBT are by Ohio Brass, and their logo is usually a letter B inside an O. They added an S and T to make SBT when it was a Silent Type insulator made to reject AM radio interference!

Here is a photo of a utility pole three blocks from my house. They don't use glass anymore, but they seem to have ceramic and fiberglass/plastic ones nowadays.


The above photo is weird because I was testing a telescope eyepiece that I was making out of old film projector lens parts.

People used to collect glass insulators a lot when they were still in use. Look around your neighborhood and imaging every boring brown modern plastic insulator was a blue or green or clear glass one! Back in the day you could go root around the base of any telephone pole and have a good chance of finding a discarded glass insulator.

I figured I'd never get a chance to find one in the wild, but then this happened fifteen feet from my front door:


I rooted around and found the tiniest brown insulator in my collection and some cool hunks of metal used as brackets at the base of this pole. The utility company came and put a second pole next to this one and just bolted them together! It's still leaning like this, but I got to find cool parts under it.

Here is the "fixed" pole now:



Next time you're outside, poke around in the bushes near a utility pole: you never know what you'll find hiding in there.



No one will find me! Meow.