Back into tumbling (rocks)

 kw: hobbies, rockhounding, lapidary, rock tumbling, jasper

In March 2008 my brother and I went into the upper Mojave desert, to Lavic, to collect jasper. I wrote about the experience at the time; this post includes several pictures of the jasper. This is a view from the collecting area on Lavic Lake, north toward mountains above the Sidewinder Dunes, a hiking area. The colorful mountains are part of the same series of ranges that includes Calico, which is to the northwest, closer to Barstow.

Looking down near my feet from the same spot, small chunks of the unique jasper known as Lavic Jasper are scattered everywhere. Rock collectors call this "float". More than a dozen pieces of red and brown jasper are seen in this picture.

My wife and I had collected here a few years earlier, but brought back only about ten pounds of rocks. This time my brother and I gathered closer to 30 pounds. 

After I got home I bought a small rock tumbler—on this trip I had visited the Diamond Pacific store in Barstow and obtained grinding grits and polishing compound—and began to tumble in earnest. 

I wore out the cheap tumbler I had bought, so I did more research to get a better quality one. I bought a Thumler's Tumbler, and it has the staying power I need. I finished the last batch of really "clean" stones, those with no serious cracks or pits, in 2012, and reported on the that batch then (with more pictures of the lovely material). I replaced the drive belt once during those four years of on-and-off tumbling.

A couple of months ago I decided to go through the remaining rough material and pick out some that might be worth tumbling. I eventually settled on about six pounds of chunks and pieces, weighing between 10 and 120 grams each. It's best to tumble a range of sizes together. The small rocks get into indentations in the larger ones and help them get abraded more uniformly.

I put just over two pounds (967 grams) into the tumbler along with an appropriate amount of rough grit and water, and set it going. After six days the drive belt broke. I ordered a replacement along with some extra parts I thought I should have as spares, such as the lid, which can wear through. Here is a picture of the larger stones after six days of tumbling. At the start they all had sharp corners.

The third one from the left in the top row features in what comes next. I like it because of its mix of red and green sections. Green is the rarest color for jasper. This picture is one of a series taken November 30, 2023.

I had weighed the stones before I started (967 grams), and I weighed them at this point (925g). The 42 gram difference is 4.3%.

I reloaded the tumbler, including a charge of fresh grit. These clearly need a lot more material removed. I let it go two weeks and then took the stone out, to inspect and weigh (842g, down another 8.6%). I took another series of photos. The yellowish stone at upper left had such a hole in the end that I decided to break part of it off. I added the 2g piece so removed when I reloaded the tumbler and ran everything another two weeks. More photos and more weighing (742g, down a further 10.3%, for a total removal of 23.3%).

I'll quickly show three examples of tumbling progress. Firstly, the green-plus-red one I pointed out above.

I did my best to take all photos at the same scale. Here we see some interesting things happening. Firstly, of course, the stone is getting smaller. The white mineralized crack is still there, and at the right, white mineralization has begun to appear at the tip of the stone. The deep crack at the opposite end shows that this stone may not be suitable for further rough tumbling. I may need to use epoxy filler. Finally, the green material is seen to be rather thin, and much of it has been abraded away. This is a further indication that I should fill the cracks and proceed to finer grinding and polishing with this stone.

Secondly, one of the red stones.

This stone began substantially smaller than the prior one, weighing less than half as much. In the left and middle views, there is a deep gouge, which is almost totally gone in the third view. I'll probably remand this to another round of rough grinding to see if some of the whitish areas can be removed.

Thirdly, a greenish yellow stone with red striping, quite a small one. It started out as about ten grams.

The smallest stones lose the most proportional mass. This one has lost nearly all of the big gouge, so it is almost ready for finer grinding.

This batch of stones is presently set aside while I rough grind another batch. I noticed that the two sessions of two weeks' duration resulted in a slurry containing no trace of the coarse grit I started with. The six-day run still had plenty remaining (which I added back in). For the batch that is running now, I'll start with a ten-day run, and adjust run times to just barely use all the grit.

It will be several weeks before I have more to report. My plan is to do rough grinding on all six pounds of stones, then select which ones to continue with for finer grinding and polishing, or mix-and-match them into two batches for finishing.

CW - still useful after all these years

kw: amateur radio, hobbies

In 1978 I began graduate school. My major professor was Dr. Wm. Roggenthen, fresh off the boat, so to speak: he had spent a few months of 1977 on Leg 54 of the Deep Sea Drilling Project, aboard the Glomar Challenger. At a bull session one day, I mentioned that I was a ham radio operator, working on my Morse Code skills so I could upgrade my license. A discussion ensued about the requirement for Code, and whether it was still useful. Bill told this story:

The ship was a few days out of port, and it was time to order supplies to be loaded when they arrived. There was a major solar flare that day, and a magnetic storm had nearly shut down radio communications. Bill happened to be present when the radio operator opened a drawer, took out a "speed key", and proceeded to make contact and transmit the entire shopping list via Code. He said CW (a radioman's nickname for Morse Code) could get through when nothing else could.

The end of 2012 marked 100 years of amateur radio licensing. For 95 of those years, CW skills were required for most licenses. The standard progression when I was licensed in the 1970s was

• Novice Class, requiring 5 word per minute (wpm) CW hearing ("copying") and transmitting, plus a written test mainly about regulations.
• General Class, requiring 13 wpm CW and a written test about both regulations, some math, and radio theory and practice.
• Advanced Class, also 13 wpm (you didn't have to take the CW test again), and a tougher written test.
• Extra Class, requiring 18 wpm CW and a very demanding written test, including special regulations regarding satellite transmissions (Extra operators were, and probably are, allowed to own satellites. They just have to get someone to launch them).

There was also a Technician Class that didn't require any code. There were no Tech privileges for using the bands below 30 MHz. For me, that's where all the fun is. During about two active decades, I used MF (medium frequency, 0.3-3.0 MHz, and for a ham, the 1.8 MHz band, or 160 meters) and HF (3-30 MHz, or all the ham bands from 3.5-28 MHz), exclusively. 160m is a fun band if you have room for a 80m-long dipole (some 270 feet, too long to fit on most suburban lots)...or you are creative with loading shorter antennas. I actually spent most of my time on 15m and 10m, which are best during periods of high solar activity, except during magnetic storms.

Solar Cycle 21 (1979-88) was a great time to be a new ham. It was an intense cycle, noteworthy in a century-long period still called the Modern Maximum. I lived in South Dakota most of those years, and aurorae were frequent. On a couple of occasions, a strong aurora seemed to form a solid sheet in the sky that lasted for hours. That sheet could bounce a radio signal. Those nights, 10m (28-29.7 MHz) was "open" on aurora-hop throughout the continent. Normally, 10m is a day only band.

During the year I was a Novice, of course I used only CW. That was considered part of necessary training. Once I earned General and then Advanced Class licenses, I naturally spent most of my air time on the microphone. But I have a fondness for CW. The club I belonged to for several years liked to work certain on-air contests. We had a few members who could cook along at 25-30 wpm, so they operated during contests. They'd listen to a signal and answer at the speed the remote station was using, usually in the 15-20 wpm range. I found after a half day listening in, that I could follow along and get nearly everything, "copying by ear" (CW station operators write everything down as it comes, called "copying". Few people can write faster than 20 wpm, so faster operators copy using a typewriter or keyboard. Nowadays, they copy right into their laptop. Lots of CW enthusiasts have hardware that sends and receives/recognizes CW for them, but it's considered cheating to do that in a contest).

Most folks don't realize the low signal strength most amateurs use. My transceiver produces 120 watts PEP (peak envelope power) for voice, and about 80 watts CW. Amateurs are allowed to use amplifiers up to a maximum of 1,500w PEP or 1,000w CW. A typical AM radio station uses 5,000-15,000 watts. The big "clear channel" stations use a maximum of 50,000w PEP. FM stations can use much more power, and 250,000w is common. Even in a good year with a quiet sun, only clear channel AM stations can be easily heard over large areas of several states, or even nationwide when there is skip. Radio frequency (RF) noise in the upper atmosphere drowns out faraway stations. FM stations use much higher frequencies that very rarely skip, so even with a lot of power, they are seldom heard more than 100 miles (160 km) away. The reason they use so much power is to overcome solar noise, and they can be heard even during most magnetic storms.

When conditions are good, or even moderate, a 120w transmitter can send a signal anywhere on Earth. When they are very good, you don't even need that. I've talked to hams in Europe and Japan using 5w. But when a magnetic storm hits after a solar flare, most of the bands shut down for a day or so.

We are presently in Solar Cycle 24 (2008-2019, estimated). Cycle 23 was only about half as active as Cycles 21 or 22, in terms of solar flares and magnetic storms. We have become used to radio that is more reliable than it was in the peak years in prior Cycles. The peak years of this Cycle will probably be 2013-2015. I wonder what will ensue? You can't always rely on cell phone or satellite phone communications when an X-class solar flare hits. Amateurs don't need to know CW any more. I hope commercial operators do. I hope ships at sea still carry radio operators who can send a shopping list—or a Mayday!—by CW if needed.

Visual sorting

kw: observations, visual skills, hobbies

I managed to collect all the 50 US State quarters that were produced since 1999, plus the US territory quarters that came out afterwards. When I got a duplicate, I gave it to my wife, and she also kept most of the State quarters she encountered. She has them all in a box, at least until this morning.

She decided to put them in Whitman folders, and asked for my collection to use as a model. Now, there are two ways I can think of to accomplish this task. One is to use preprinted folders that have each state and year, plus P and D mint marks, so there are two each. Then you just go through, coin after coin, and find its spot in the array.

She only wanted the backs shown, and doesn't care about mint marks, so she got blank folders. The second way is then to sort them into years, because there were five quarters minted each year. Then my collection could be used as a model to get each year into the right order. She did it a third way, a way I could not have used.

She spread them all out on the table, face down, and just looked at them for a while. Then she looked at my coins, muttered "Delaware", unerringly picked out the Delaware coin from the array and put it in the first spot in her folder. She continued with New Jersey, and so on. When I asked why she didn't sort them by years first, she told me she was just using the picture on the back of each coin. She could see it better than the year.

Somehow, probably subconsciously, she had spent no more than a couple of minutes looking at the spread of nearly 100 quarters on the tabletop, and sorted the pictures on their backs. Her visual memory really amazed me. No wonder she always wins at MasterMind!

Planting time - for the bees

kw: citizen science, honey bees, bees, hobbies

It is time to get those Lemon Queen seeds and start a new batch of sunflowers! I had a fun time last year gathering and reporting bee sightings as part of the Great Sunflower Project. But it'll be late May or early June before I have new sunflowers blooming. (This image is from The Dailygreen, an article on citizen science.)

I am hoping in the future the Great Sunflower people introduce a project that begins earlier in the spring. My apple tree has already bloomed and dropped its blooms, as have the crab apple and flowering pear trees. They engendered quite a bit of bee activity for just a short time. The dogwoods are in bloom, but don't seem to attract bees. By their smell, I suspect they are pollinated by flies. I am sure there is some reliable pollen-producing flower suitable for extending the bee counting activities into mid or late April and through May.

Until then, this year I'll plant the sunflower seeds indoors to give them a head start in my sun porch, and put them out when they get flower buds.

Time to switch the screen saver

kw: hobbies, photographs, astronomy, galaxies

You really ought to click on this image to see the larger version (~1,000 px across); this 400 px version is just a bit puny.

I really appreciate the many observatories, including the space ones, that post large, high-resolution images on their web pages. A number of "wallpaper" web sites also post lovely images in their Nature sections. I downloaded these images and others for a specific purpose (my enjoyment), and cropped or resized them to the same dimensions in a 1.6:1 format.

I recently decided it was time to go for a new look with my screen saver. I like the "My Pictures Slideshow" supplied by Microsoft, and I have several folders that I switch among from time to time. For several months I've been showing pictures of various mineral specimens, some that I took of my own minerals, and some downloaded from museum and rock store web sites. Now that I've been classifying galaxies for several weeks in Galaxy Zoo, I decided to show some galaxies that are close enough to home (all less than half a billion light years) to make good subjects for "astro cheesecake".

Although spiral galaxies are the most interesting from a visual perspective, most galaxies are elliptical, such as the first thumbnail in the second row above. Galaxy clusters are typically dominated by one giant elliptical galaxy that is busy consuming its neighboring galaxies, and heavily populated by medium-sized to small elliptical galaxies. About 40% are spirals. The Local Group that includes The Galaxy, the Milky Way where we are, does not have a giant elliptical within it, but contains a number of smaller ones, and only three large spirals, the Milky Way, the Andromeda galaxy M31 and the Triangulum galaxy M33. The Local Group is part of the Virgo Supercluster, which is centered around a pair of giant elliptical galaxies. The fifth and sixth thumbnails in the second row above show central portions of the Virgo Cluster and the Coma Cluster.

When I was a child, I was fascinated by galaxies, and learned to "draw" rather realistic ones on a chalk board by rubbing colored chalk on an eraser and then blowing the dust onto the board. It is quite time consuming. None of these ephemeral artworks was photographed, more's the pity.

C60 in paper - partial success

kw: hobbies, photographs, mobiles

More than two years ago I posted instructions for making an origami module for a "spiky edge polyhedron". This followup has been a long time coming.

I decided to make a shape based on the geometry of a buckyball, or buckminsterfullerene, or C60 (formally, C₆₀, but I'll forgo the subscript codes, as most writers do). The 60 carbon atoms in C60 are held together by 90 bonds, and the origami modules I am using correspond to chemical bonds, so I needed 90 of them. I decided to make it colorful by making the 60 bonds that surround pentagons to be of five colors, and using a sixth color (gray) for the rest of the bonds. I spent months doing one or two of these per weekday, because it is really tedious making more than a couple at a time.

The dihedral bond angle needed for C60 is about 20°, while the smallest dihedral that is practicable with these modules is 36°. Thus I know there will be some steric strain; the ball will "want" to be a lot smaller than I am making it, and will strive to close early. Fortunately, paper ought to be flexible enough for this to work.

I began by putting together the twelve pentagons. Here are two of them. That used up all the colored modules. By inserting a tab from each into a pocket of the next in round-robin fashion, I have a tab left at each corner for connecting to the gray modules that will hold the pentagons together while outlining the hexagons.

This shows the twelve pentagons laid out in a planning pattern, ready for me to connect them with gray modules. There are several ways to color a buckyball, and I can see that this is not really the most symmetrical, but it will serve.

To make the twelve pentagons, I just had to insert one tab into one pocket at each step. From this point, I have to insert two tabs into two pockets simultaneously, and do it properly sixty times (once for each end of the linking module). Sorry, but I neglected to photograph one of these double-tab insertions.

Here is a top view once the first five linking modules and five pentagons have been assembled around the one chosen to be central to the building process.

This is an oblique view at the same stage. Just below center you can see where a linking module will be put onto a pink and a purple tab to complete the facing hexagon. The hexagon is trying to be a pentagon-and-a-half, showing the steric strain I mentioned. The dihedral bond angle these modules are built for is actually better suited to attaching the twelve pentagons together without linking modules at all.

Look closely at where the pink tab bends away from the pink module it is part of. There is a blue tab going into the pink module's pocket. The blue pocket is open. When I attach one end of a linking gray module, its tab will go in the blue pocket, and the pink tab will go in the gray pocket. I insert them halfway, apply Elmer's Glue-all, then push all the way in and press tight for a bond.

Shapes without steric strain can be assembled without glue, though they slide apart at a rather light touch. I glue all shapes since I want them to last for years.

Here is the completed ball. It was a bit of a tussle getting the last five linking modules and the final pentagon in place. The hexagons and pentagons are showing a bit of distortion, another symptom of the steric strain, but the piece is quite pretty nonetheless. Over the coming months (years?), I'll produce some less elaborate shapes to go together with this one, the centerpiece for a new mobile.