See Atomic Particles With Your Own Eyes Part 4: Inferrence via Ion Induced Voltage Fluctuations (Welcome to the Ion Chamber)

So You Wanna See Atomic Particles With Your Own Eyes Part 4: Inferrence via Ion Induced Voltage Fluctuations (Welcome to the Ion Chamber)

There is more to seeing than what meets the eyeball.

-N.R. Hanson, Patterns of Discovery

We've explored actually seeing the paths of particles in a nuclear cloud chamber; watched corruscating alpha particles slam against a phosphor screen in spinthariscope; watched them explode when crossing the high voltage spark detector; found fields of activity with the radio telescope; and just horsed around with regular old Geiger Counters for fun. 

It's time to mix low voltage (8.5v) with soldering, multimeters and aluminum foil to make an Ion Chamber.

Simply put: we charge a cookie tin and have a wire inside that acts as a cathode. As ionized particles enter the chamber they create a current flow that is displayed on a multimeter. The higher the volts, the more ions which means greater radiation. 

Cookie tin. 

Screws that join the circuit board physically and electricity to the tin.

The cover of the tin becomes a circuit board cover.

I soldered a wire to the middle post of a Darlington transistor.  This is the cathode that passes through the bottom of the circuit board and into the tin. The Darlington transistor is actually two transistors in one package. The first part amplifies the incoming current, the second amplifies it even more!

A guy named Sid Darlington actually patented the idea of putting "two or three" components into a single unit back in the early 1950s. Not sure how momentous this was. Um, "let's moosh together two pizzas and make a mediocre double-pizza with a soggy crust center." Yeah, no! I think he actually figured out how to do it though, so it wasn't just the dopey idea of smashing them together that was his claim to fame.

Anyway, it acts like a single transistor but it amps up (high gain) the input. However the first of the Darlington ‘pair’ sucks up the voltage and responds in the circuit, leaving the second built in transistor a little ‘hungry’ for more. 

Think of it like two cats in a single cage: first one gets enough food, the second doesn’t so it makes for a really jittery pair of cats. That’s generally bad, but how can we use this to our advantage? 

Darlington Pairs are very jittery = very sensitive! They make create components in touch sensors. What are we doing? Well, we’re building a sensor that detects when it is touched by tiny little ions right? Great! How can we increase the jittery sensitivity of this? By adding that long wire to the middle leg of the Darlington transistor and extending it into your ion chamber. Neato!

Here's a photo of the wire coming off the Darlington straight at the camera.

By the way, I ordered the circuit board and transistor from Madscientisthut.com. They're neat people, ship fast and have cool stuff. You can order an ion chamber kit from them in various ways. In one of the kits they'll even through in a multimeter!! Or you can buy the board and source the parts separately from Radio Shack or wherever. I've found that usually on Amazon you have to buy 100 of the same components-it's cheap, but do I need 100 Darlington Transistors for $5 and free shipping? No, that's where kit designers like Madscientisthut.com come in and make everything easier.

I do order capacitors in bulk, because I get weird and blow lots of capacitors. A just received a bag of 100 capacitors from Amazon, which was a good deal and convenient...as you'll see in my next post about linear laboratory bench power supply making (there will be a loud bang and a little smoke!). 




Ok, here is the circuit board mounted on the cookie tin.

The inside of the cookie tin with the cathode wire in place.

The open end of the tin is covered with aluminum foil. I roughly zeroed out the meter.

Here is that meter during testing with a uranium test source (upper left above the foil).

Back view of the unit with the circuit board guard off and meter reading 15.1 mV. Notice the vial with uranium placed behind the ion chamber.

I moved the uranium to the front (sensing) side of the chamber. Notice the meter has started climbing.

Here's a nifty video I made of it in action. All of this was done before I properly mounted the circuit board deflector guard.

With the circuit board guard professionally mounted (with two different kinds of tape) I can now turn the unit on and use a plastic screw driver to zero in the unit by adjusting a 10k and  a 100k potentiometer through the holes.

Not something I'd have in my carry on luggage, but it works and only took me two nights to build.

The first night I was soldering and half my house went dark. Apparently the 240v electricity from the pole gets split into 120v when it gets to the fuse box. Sometimes with a blown utility pole transformer half the box can go out: either the left side (odd numbered fuses) or right (even numberr fuses) loses power. My basement, garage and half my kitchen worked fine.  All the other rooms had dim lightbulbs that slowly went dark.

"How can a soldering iron cause this?!?"

I finally looked outside and saw the street lamps going dark and realized it was a power line/pole problem. For a few minutes as I sat in complete darkness holding a blazingly hot soldering iron I thought I fried my house wiring.

I got to bed at 3am with a power company using a gas-powered generator backfeeding the pole by my bedroom window. Backfed with a regular old orange extension cord up the pole.  It's very important to wire in emergency generators for your home properly: if you backfeed your house with a male plug to your wall you can kill a utility worker.

Wait, so it wasn't the catnip, er, I mean soldering iron that made the lights in the house look like lava lamps? Still seems dark in here, I can't tell if I'm standing in a pile of loose Darlington transistors or those 10uf decoupling capacitors for the laboratory power source being built for the next post...meow.

Non-Newtonian Fluid is the Best Kind of Fluid

Non-Newtonian Fluid is the Best Kind of Fluid

In my continuing assault on Isaac Newton I will demonstrate how boring old Newtonian fluids (like water) are less fun than non-Newtonian ones. First, we need to get our hands on a non-Newtonian fluid.

To make a non-Newtonian fluid we can just mix laundry spray starch and white glue. This will make a shear-thickening non-Newtonian fluid. Under stress it thickens and hardens (increases viscosity), once the stress passes it turns into a runny liquid. Put it in a cup and its like white glue you can stir with your finger. Poke your finger into the cup forcefully and it will harden into a single blob and you can pull it out of the cup!

Here's how quickly it is to make, it's actually easier without the gloves-they're too slippery to get a good gauge on the mix:

Here's my non-Newtonian fluid in action. Slap it and it hardens enough to let me peel it up off the plate. Wait a second and it'll drizzle down as a liquid:

There are many variations of non-Newtonian fluids besides shear-thickening ones.

Ketchup is a shear-thinning non-Newtonian fluid, which is why people smack (shear) the ketchup bottle to get it to thin and flow out faster. Xanthum gum is added to ketchup for just this effect.

If you put this spray starch and white glue mixture in a ketchup bottle the only way to keep it from pouring out would be to keep smacking the bottle! If you wanted it to thin and flow faster your just leave it alone for a few seconds. If you slap it hard enough it will instantly harden and break into two pieces, only to flow back together of left alone for a few seconds.

It seems pretty weird, but I've dealt with having a non-Newtonian fluid and the problems that it can cause:

I play a variety of bowed instruments. Rosin is used on the bow to let it grab the strings of the violin, cello or as in the photo above a double bass viol. The rosin looks and feels like a cube of yellowish glass:

This is the harder rosin I've used for years, but recently I started playing the huge upright double-bass which required me buying newer, softer rosin. It's in the red canister next to the violin. The softer rosin seemed like regular rosin: hard, produces a white powder when rubbed with the bow and will shatter into a zillion pieces if hit with a hammer; however you leave the canister on its side after a few days the seemingly glass-like rosin will ooze out. Leave it as a blob on a shelf and it will slowly pancake out: spreading and flattening, and eventually oozing off the edge.

Now, some people will tell you that regular old glass is a fluid that oozes over time, but they're wrong. Glass is a solid, although it isn't a crystallized solid so it's an amorphous solid. Crystals are rigid lattices of ordered molecules. Fluids and gases are unlatticed unordered molecules. Glass is unlatticed, unordered yet rigidly bound. Glass is a solid.

Most rosin for instruments is a solid, so solid on fact that it sometimes crystalizes. However bass rosin is much softer relative to regular rosin-although if you found a piece on the sidewalk you'd probably assume it was a chunk of old, broken glass.

Common myths: old glass windows are thicker at the bottom because the glass oozed down. Wrong: the spun old glass and cut it, the outside edge was always thicker and it was installed thick edge lower. A glass shelf will bend in the center over time so it's an oozing liquid. Wrong: it bends for the same reason wood shelves bend, it was too thin and/or too overloaded or gravity just got the best of it.

Polymers are repeating molecular units. They tend to create semi-crystalline structures and glasses. It tends to make things "plasticy" and in fact it gives the name for polystyrene is polymer of styrene (styrene being obtained from benzine).

What else has a crystalline structure? The starch spray in our non-Newtonian fluid. It has a semi-crystalline structure, that helps bind the glue into big molecules that are a polymer. Starch itself is considered a polymer. Adding a little borax powder* to the mix would make it a stronger polymer--strong enough that it would stop being a thinning/thickening liquid and become a rubber-like blob that you could throw and bounce off the walls. If you add an enzyme it will break the polymer up into smaller units (monomers) which changes its properties. Stringing together units of silicon yields a semi-liquid silicon polymer, which we call Silly Putty!

*Borax powder is sodium borate a natural compound of the element boron, which is what you want to get in the laundry aisle.

Boric acid is hydrogen borate is an acidic form of borax that is either a natural compound or manmade using the element boron with sulfuric or hydrochloric acid; as such it is acidic. Borax crystals are usually crystallized boric acid. They are sort of not the same. Kind of like ice is frozen water and good for putting in soda, ice dipped in acid is not quite the same.

Boron is B
Boric Acid is H3BO3

Borax is (NA2B4O7)(10H2O)

When dry boric acid crystals are added to water it grabs electrons and becomes weakly acidic. This weak acid is used in eye washes and hygiene products to combat yeast.

You'll also remember boron in its elemental form has awesome properties when used to lace blocks of paraffin wax during out experiments with slowing down radioactive neutron particles in my previous post "My Radioactive Dime".

Where else is boron/borax used? Taxidermy!

This is part of my Game fowl Collection: photo-books by Hiro; my bird Alouicious (named after the teddybear from Brideshead Revisited); and copies of Feathered Warrior (a catalogue where you can buy fighting spikes and the live-fertilized eggs of *past* fighting champions). 

Alouicious is actually from an organic market in Rochester Hills - not a fighting bird (so if you were upset when you thought he died in a cockfight, but relieved he was just normal food-then you're a hypocrite, unless you're vegan). LOL.

Here's a pic of my room-mate Boris the Book Boar visiting Melvindale Public Library during a charity event.  He came all the way from the Black Forest in Germany!

As you can see, boron is very useful! But enough of boron for now, it's time to get back to starchy polymers...

Boron has an incomplete set of electrons (in a compound) and seeks them out to bond with. This gives boron (not boric acid) many uses in the adhesives industry, including mixtures involving our good old friend starch! I see this all the time (I'm a librarian) in bookbinding pastes. One great glue for paper (used to make cardboard poster tubes) made from a water soluble synthetic polymer is polyvinyl alcohol (PVA) with boric acid added to it. 

Usually polyvinyl alcohol (PVA) has a formula of (CH2CHOH)n), but this particular chunk of PVA is actually:

 (-(CH2CHOH)n-(CH2CHOOCCH3)m-)

PVA is sorta weird in that it's not made up of chained monomers, it's polyvinyl acetate that is polymerized, and then the acetate is converted to alcohol! It's very bouncy:

PVA is  (CH2CHOH)n or it is -(CH2CHOH)n-(CH2CHOOCCH3)m-

Glucose is C6H12O6

Starch is C6H10O5

As a side note: the specific gravity of this PVA ball is 1.24 according to the MSDS (Material Safety Data Sheet) provided by the manufacturer, Chang Chun Petrochemical. It sinks in water, but if you tip the bowl it's in it only slowly rolls to the lower side.


Here's a weird enzyme vs polymer test: chew a saltine cracker. Your saliva will break up the polymers and the crackers will get sweeter and sweeter as you keep chewing (and not swallowing) and adding more crackers. The monomer of starch is glucose. Glucose is a simple sugar. Simple sugar is sweet. It's the enzymes in your saliva (not the acids) that do this.

As a polymer, starch tastes like bread or potatoes. Break it up into its glucose sugar monomers and it's sweet! Glucose attracts water around it. Starch just attracts other starch around it. Glucose grabbing water can cause swelling and other problems-especially in the bloodstream of humans. It also causes plants (which store sugar/energy in the form of glucose) to need more water to make the glucose happy. The result is thirsty plants.

Many plants have wised up and stored their glucose in the form of longer chains of starch: the plants aren't so thirsty and the starch isn't bothered by whatever water is in the plant (too much water can mess with the glucose storage). Glucose in plants and animals calls for a balancing act with the amount of water, starch doesn't really care so much.

So...I guess have to find someone besides Newton to blame for the constant barrage of cantaloupes "oozing" off the glass table? Cantaloupe polymerization via face rubbing? I don't want to be taxidermied. Meow.

Oink!