The Microscopist's Mate, part 4 of many

Just for the record, all of what you find here, and in the other blogs in this series, is now available in fuller detail in my e-book Looking at Small Things.  Go to this link to find out more about how to get the free low-resolution copy, or the cheap high-resolution version: I'm a professional writer, so I like selling books, but I'm also a professional educator, so I like sharing ideas.

There's a similar free or cheap deal on offer for my Playwiths ebook as well, and to see what else I have been doing (LOTS!), go to this link.

Here are the links to Part 1, Part 2 and Part 3.

This time, we are looking at coins and notes. Under magnification, most coins show scratches, most notes show fine engraving. Take a close look at this coin, which any Australian will recognise.

A reader who looks at any of my science-related books will be familiar with the coin as well, because I use the Australian 50-cent coin as a standard scale. The coin is 32 mm from side to side, and my reasoning is that in my lifetime, this coin is likely to remain in circulation.

That is why the 50-cent coin appears all over the place here, with redback spiders crawling over it, or lying beside a fossil or a rock. (See here, for redbacks and coins.)

Puzzle your friends

Now take a look at this image on the left: do you recognise it? I came across it, and even though it was a shot I had taken with the Go Micro device, I had to check where it came from.


Find this part on a 50-cent coin and take your own photo: see if your friends know what it is. Or of you prefer, choose some other coin and try it out.

Coin details

Then try some of the other Australian coins, and here, you need a couple of new words: the side of the coin that we call “heads” is actually the obverse to coin collectors, while the “tails” side is the reverse. You also need to know that the details are easier to see on a shiny new coin.

Can you find the initials of Stuart Devlin who designed the reverse of the 5, 10, 20 and 50 cent coins? Can you find two (or more?) different sets of initials for the different designers of the head of Queen Elizabeth II on our coins? Can you work out when the design changed?

No, I don’t know who those people are: see if you can find out. I only know of two, but look at some older coins, once you know where to look.

Over time, coins get scratched, and obviously older coins are more scratched, on average. But out of our “gold” coins and our “silver” coins, which ones seem to be more scratched?
 

Looking at notes

Here are three images taken with the Go Micro from the new Australian $5 note: would you recognise any of them? The third one might be a give-away, but the others aren’t that easy.

   
Now here are five Go Micro shots of parts of the new Australian $10 note: once again, the last one is the give-away.

   
If you can find an old Australian penny, KG was George Kruger Grey (not “kangaroo”, as I used to think).

HP who designed King George VI (pre-1953) was Herbert Paget.

Guess who was quite a keen numismatist, back in those days?

Ah, yes, I said it would be green slime, didn't I?
Well, the cultures are still maturing... i will get there, one of these days.

The Microscopist's Mate, part 3 of many

Just for the record, all of what you find here, and in the other blogs in this series, is now available in fuller detail in my e-book Looking at Small Things.  Go to this link to find out more about how to get the free low-resolution copy, or the cheap high-resolution version: I'm a professional writer, so I like selling books, but I'm also a professional educator, so I like sharing ideas.

There's a similar free or cheap deal on offer for my Playwiths ebook as well, and to see what else I have been doing (LOTS!), go to this link.

Here are the links to Part 1 and Part 2.

Today, I will be talking about a neat little trick for lighting, not the green slime I said I would be on about. What I actually write about here depends on what I am working on, and yesterday, I had an idea.

There are going to be times when you want to shine a light through a specimen, especially when they are looking at slide mounts. I have messed with a few rigs, and I will be building a more sturdy one, one of these days, but here’s a quick and dirty version.

The good thing about quick and dirty versions is that you get the wrong steps thrown in as well, because that detail will help you make a better model for yourself. here's how I started this adventure, by gathering the items below:

What you need: a jar, a headlamp with LEDs, scissors, and some translucent plastic cut from a milk bottle.

 After I took this shot, I added sticky tape to the list. I used a 400 gram jar, because you can sit a microscope slide on top. These next four pictures tell the story.

     
I realised as soon as I tried this out that the camera microscope was focusing on roughness in the plastic, so I replaced the plastic with a piece of tracing paper and stuck that to the jar.

In my final version, I plan to have the diffusion layer (the plastic) 2 cm below the slide, but for now, I am using this arrangement to steady the camera.

Remember that one of my major concerns will always be camera shake. The Go Micro clip-on is resting on a microscope slide that is across the jar. It’s primitive, but it works!

The first rule of gadgeteering, though, is never to give up while you are ahead. The next morning, I spied one of those clear plastic throw-away containers that, typically in our house, had not been thrown away, but been used to store something important, like pieces of string too short to be of any use. Anyhow, it was pressed into operation, but an image of the base showed through:

I could work around that, but  I went straight to Mark III, seen in the second and third shots. This one uses a square flexible plastic box that is just sturdy enough.

 And here is how it looks when i light the head lamp:

The thing is, though, that the morning I did this, I had some sand samples that were dry enough to look at, and for most purposes, you don’t want back-lighting on sand (yes, I have some plans to work with crossed polarisers later, but this is now). So needing a light from above, I reached for the original Mark I and a bit of black cardboard, and took these next two shots.

I could have done without the slide here, just laying the sand on the cardboard, but I had something else in mind. Using the paint brush, I spread the sand out and got the shot below, a 9 mm diameter field of shoreline sand taken from St Heliers Bay in New Zealand.

I am conservative about the biosecurity of specimens like this, so even though marine sand is not an import that must be declared, all my samples were both microwaved and baked in an oven before they came anywhere near Australia. Sand from freshwater lakes, on the other hand, must be declared, but my interests are fully taken up with marine sand.

Anyhow, that has solved most of my present lighting problems, and I hope it has helped with yours!

Maybe next time, it will be green slime time, but then again, it might be sand or pill bugs, which used to be sold as a cure for all sorts of ills.

The Microscopist's Mate, part 2 of many

Just for the record, all of what you find here, and in the other blogs in this series, is now available in fuller detail in my e-book Looking at Small Things.  Go to this link to find out more about how to get the free low-resolution copy, or the cheap high-resolution version: I'm a professional writer, so I like selling books, but I'm also a professional educator, so I like sharing ideas.

There's a similar free or cheap deal on offer for my Playwiths ebook as well, and to see what else I have been doing (LOTS!), go to this link.

This follows on from Part 1, obviously. If you don't read that first, you will be lost.

Today, the topic is sand, and microscopy using a cheap clip-on lens with a Samsung tablet.
The first sample is wind-blown sand from St Helier's Bay, Auckland, New Zealand.

No digital zoom, with the Go Micro

Full digital zoom applied to the Go Micro. This is part of the same field.

I got curious about the make-up of sand some years ago, when I tried to work out why some beach sand squeaks, when you walk on it.

That was when I discovered that there’s quite a lot of shell grit in some sands, little broken-up fragments of shell, as you can see in this shot of sand from Coller’s Beach near Mollymook in NSW. The shot on the right was taken with a fairly high-end microscope.

Fast-forward, and I was on a beach in New Zealand, two weeks ago, sampling up and down the beach. I had a thought: why not sieve the shoreline sediment and see what bits are there? For that, you need a sieve, and I remembered one of my favourite gadgets, a sieve jar: here’s how to make one.

A sieve is just a screen that only lets through something smaller than a certain size. A cat flap is a sieve that lets cats through, while stopping Dobermanns. Gardeners use a garden sieve to take out rocks and pebbles from garden soil, and so on.

I think I got the inspiration for the sieve jar from a gadget another scientist was using to investigate tardigrades. I use a 400-gram Vegemite or a 400 gram plastic peanut butter jar for this because these jars have a wide mouth, they are a good size and their lids are made of soft plastic.

To make my sieve, I take a soft plastic top from a jar, set it upside down on a piece of scrap wood and used a hammer and a small (1 to 1.5 cm) chisel to make a set of cuts that let me remove the flat top, leaving just an open ring. 

(Left) Cutting out the top of a jar lid to make a screw-ring. 

Then I used a square of flywire and attached it to the bottle, as shown in the picture below. Then, all I have to do is half fill the jar with leaf litter, and shake it gently over a white dish, watching to see what drops out, pootering my finds up so I can examine them. 

(And what’s a pooter? Try this link.)

Trim the corners, and you are ready to go. There is just one warning: small hands and jars made slippery in water, near rocks: can you see the problem? Plastic peanut butter jars make safer sieves for young users!

Most beach sand has just a few interesting shells, along with a lot of small sand grains, but I will come back to that when I get to looking at sand. This new use of the sieve jar occurred to me in February 2018: I expect that my readers will find new uses in their turn, just as I still do.

Once you have a sieve jar, the rest is easy, but choosing the right sort of beach is hard. Ideally, the sand grains will be fine enough to pass through the sieve, leaving you with a collection of broken bits to work through. I seem to get the best yields in sand 10 cm down in the wave zone.

This is the kit I take out with me, along with a notebook so I can
record where each of the jars was filled.

The trick is to fill the jar ¾ full of sand, rinse off the sand around the rim, screw the lid down, and then shake the sieve vigorously in the water. I put my other hand under the jar, so I can tell when sand stops falling out, then I tip or wash my catch into a second jar. I have a toolbox that carries six labelled jars and the sieve jar.

In the next shot below, I can see a quartz pebble, top right, a brown glass fragment, 1/3 of the way down, 1/3 of the way in from the left, and a small brown and white conical snail, 2/3 of the way down in the middle, fragments of dark blue or purplish shell, probably from cunjevoi.

I can also see several sea urchin spines (you may not see them, but you will see them below, shortly), bits of limpet shells, and somewhere in there, there was a tiny fish vertebra, or backbone segment. 

If you know the rocky shore shellfish, you will also see Bembicium, Melanerita and limpets, but who knows what else is hidden under the surface?

The trick to finding all the treasures is to spread the grit out as a thin layer in a white dish, and let it dry in the sun before you push the pieces around.

You can use a small paint brush for that, but I prefer to use tweezers, so that when something good comes up, you can pick it up and drop it into a Petri dish. There are sea urchin spines in the dish.

 In the pictures above, there was actually a bit much material, but it was still wet, so I just dumped it in there to take the shot. Notice the white dish, the tweezers and the Petri dish. The jar on the left is what I carried my catch home in.

   

My standard white dish is also good for sorting. The interesting bits go into the Petri dish, and now, you can see the sea urchin needles quite easily, but they will be clearer in the next two shots.

Now all we need is a microscope!

Shells are well within the reach of the Go Micro clip-on, or even a hand lens, so sand-sieving is one of those activities that can be adapted in many ways.

All of the pictures after and including the picture on the right were taken with a Go Micro clip-on — and these shots are just the beginning! Move in on your local shells, and see where it leads.

   

The shell is about 5 cm across (left, above), and on the right, it is as revealed by the Go Micro.

 

Looking at shell fragments

Now follows is a picture essay. First, here are the original subjects for the first batch:

Now here are some of them as seen with the Go Micro: the pictures represent an area of about 1 cm x 1 cm. From that, the reader can work out the magnification as they see it.

(Left and centre) sea urchin spines, (right) an unknown shell, possibly a limpet.

     

From the left, an unknown snail, a limpet and a piece of bottle glass. The identification as glass is confirmed by the stripy fracture pattern, called a conchoidal fracture.

A small limpet: specimens like this can be a bit disappointing.

When you find a shell with a small hole like this one, the animal that lived there was killed by something like an oyster-borer, also called a mulberry shell or Morula. The specimen on the left may have been killed by one of its own species, but we have no idea of how the specimen on the right died.

And by the time you are you are finished with examining sand (and maybe looking at some soil), your pond water should be ready to look at.  Next time, I will probably be looking at green slime, as I have had a set of culture bottles going: notice how they all get a free flow of gases, but are mosquito-proofed.

In other words, to be continued...

And Part 3 is now available.

The Microscopist's Mate, part 1 of many

Just for the record, all of what you find here, and in the other blogs in this series, is now available in fuller detail in my e-book Looking at Small Things.  Go to this link to find out more about how to get the free low-resolution copy, or the cheap high-resolution version: I'm a professional writer, so I like selling books, but I'm also a professional educator, so I like sharing ideas.

There's a similar free or cheap deal on offer for my Playwiths ebook as well, and to see what else I have been doing (LOTS!), go to this link.

Add caption

Add caption

I wish to announce a new book to go with an amazing new gadget that I have been playing with. I will be writing mainly about the one on the right, which can be had for a remarkably low price from the Go Micro people. 

In the interest of keeping everything above-board, I got mine for free, because I work in that field, but I have no commercial interest other than in the book I am planning to write.  I just love the gadget and what it can do, so I am writing activities that only an old and seasoned microscope fiddler would know.

People are likely to find this from odd places, so here’s a bit of background that my friends all know. I am a biologist by training, a naturalist by inclination, a fiddler by nature, and a writer by avocation. I am a grandfather by virtue of age and biology, with 500 proxy grandkids at Manly Vale Public School in Sydney, where I am a "visiting scientist".

I was recently in New Zealand, where I took delivery of two ‘Go Micro’ models seen above.These are neat little gadgets that clip over the camera lens on a smart phone or a tablet. I found that I preferred to work with my tablet, but my first day was a bit of a disaster. To be blunt, even my best friends concede that I am fast approaching Advanced Middle Age, others say the silly old b's hands shake.

That's as may be: my grandson's hands also shook when he tried it, and I know my Manly Vale kids' hands will shake when they try the rig out. We all need steadying.  I decided I needed a better rig, but until I got back to Sydney, I chose to breadboard it, as shown here, where I used books.

My first test piece was a seagull's feather, but the auto-focus had drilled down to the wooden table, but there's a fix for that: black cardboard.

You can see the result of using black cardboard here:

The next one shows what I later took for a flying ant which had the misfortune to be mistaken for a mossie (it was, I realised later still, a wasp).

Notice that some parts of the insect are out of the focal plane, but there's a fix for that, set out below.

More news from the trenches later, but my aim will be an immobilised tablet with a moveable stage, with interchangeable opaque black, sky-blue and white bases, plus a translucent and back-lit base for photographing things like sand grains (which I will deal with in the next blog on this theme).

I will need everything controlled, because, coming back to the focal plane problem I have you-beaut free software that can paste together identical shots taken with different focuses. This software comes fromthe National Institutes of Health, and it's called ImageJ. The last shot shows a composite shot of a house-fly, done with a pricier rig.

My next post in this series will be about looking at sand, because I started getting out all of the old wrinkles I know about microscopy, mostly stuff I wrote for Australian Backyard Naturalist, and I am planning to share some of it here.

It currently has the working title The Microscopist’s Vade-Mecum, but will probably end up as The Microscopist’s Mate. I also expect to be sharing my ideas with the Go Micro community.

Next time: sand, starting with this wind-blow sand from St Heliers Bay, Auckland, New Zealand.

No digital zoom, using the Go Micro

Full digital zoom, using the Go Micro.

Footnote: here are four shots, showing the coverage I got from my Samsung tablet from as close as I could get, with and without digital zoom, then with the Go Micro lens, again with and without zoom.

The tablet is 21.5 cm across, so I have magnifications of  about x3.8,  x16.5,  x24 and  x65.

Now you can also see Part 2 from this link.

Yandackworroby Pub

You can get to Yandackworroby (the name has been thinly disguised to preserve a rural haven) the easy way or the hard way.  The hard way is down the coast, then grinding along gravel and dust, all arranged in furrows, holes, and corduroy.  The easy way is an hour of suburban street crawl to Sydney's south-west corner where the freeway starts.  After that, we drive in comfort for another hour.

That takes us to our turn-off at a small ghost hamlet beside the highway.  It died when the highway came through, carrying everybody past at an air-conditioned 110 km/hr.  Now we are on back-roads, and even though each time we go there another small section has been sealed with tar, there is still enough dusty bumpy road in the next hour and a half to make us glad when we reach Yandackworroby.

The ‘towns’ of this area are minimalist.  Kelly's Ford is just a camping area, often deserted, Windyworroby is no more than a community hall, and Sassafras is merely an abandoned barn where two dirt roads cross.  In that league, Yandackworroby is a thriving metropolis, with almost a dozen occupied buildings along a 500-metre strip of road, including a small school, a shop, and a pub.  There is also a small museum that I will tell you about some other time.

An Australian ‘pub’ is cousin to the British pub.  It is a public house, a hotel, a place that serves alcoholic drinks to the public.  Most people drink beer, but spirits and soft drinks are to be had, and wine is often possible.  Some pubs are giant booze emporia, but country pubs in places like Yandackworroby are important social centres, and resting places for the passing traveller and bushwalkers like us, heading into, or out of, the nearby wilderness areas.

Opposite the pub, several large pine trees provide welcome shade, and there are rough timber tables and benches on a verandah which is shaded for most of the day.  You enter the bar through dangling squeaking screen doors that slam sullenly behind you, for this is sheep country, and something has to be done to keep the flies out.  You order your drinks, say a few words, pin your business card to the wall if you have one, and then push back out onto the wide verandah.  Time passes slowly enough for people to be able to talk to each other.

Aside from bushwalkers and travellers, there will always be a few locals who know what the rainfall has been in the last week.  This is vital information, for we will rely on pst rain to keep us in drinking water over the next few days.

Even if the creeks aren't running, one decent rain shower in the night will feed the drips in the camping caves.  With luck, we can gather a litre of water each hour at each drip.  But without recent rain, we must carry all our water with us, so we value the information we get from the farmers at the Yandackworroby pub.  Even now, in the midst of a drought, there is reasonably good water in the area, wrung out of the clouds as they blow over the surrounding mountains.

Sometimes, though, the farmers are working.  On our last visit, I slowed the car down as we approached Yandackworroby from the Kelly's Ford end, because a hand-painted sign on the trampled grass of the verge said ‘sheep on road’.  Rounding a corner, we found a mob of sheep muddling along the road, followed by a utility truck.  (A utility, or ute, is what Americans call a ‘pickup’.  Australia invented this vehicle, so I will stick with our name for it.)

One sheepdog rode on the ute, sitting on the roof for a clearer view.  Three more dogs were working the herd along the road, directed by a man who stood to one side, clear of the dust clouds the sheep were raising.  I stopped the car: we were only a few hundred metres from the pub, and my son and daughter are keen photographers.  I thought I would just wait for the mob to pass by the pub, and then drive peacefully up, but I had not reckoned on country courtesy.

The walking man looked back to us as the two teenagers got out.  He waved, and with three loud whistles and two hand signals, the road was clear, the sheep cowering on one side of the road under the baleful glares of the crouching dogs.

I drove past slowly to park in the shade at the pub, leaving my son and daughter to walk up with the sheep, taking photos as they came.  There was just enough time for me to set a round of drinks on a verandah table before they and the sheep arrived, they to drink, the sheep to mill in the road outside the pub.  For some reason, the screen door of the bar had been propped open, and several of the sheep managed to lurch aimlessly inside.  A quick word from the ute's driver, and the three hard-working dogs put the sheep back outside.  All the while, the dog on the back of the truck kept its position.  We speculated briefly that it was having a birthday.

Right next to the pub, a paddock gate stood open, and without any visible or audible instruction, the dogs drove the sheep through.  As the sheep dispersed voraciously into the fresh green grass of their new home, the dogs jumped onto the back of the ute, and the man closed the gate.  The woman in the ute parked it in the shade, and they both dropped into the pub to settle the dust.

When they came out onto the verandah, I asked about rain, and gathered some local gossip, carefully saying nothing about what we had just seen.  Then as the couple were leaving, my son wondered aloud what the dog on the back of the truck was doing.  ‘Ah,’ the man said, nodding slowly, ‘That's me spare, just in case one of me other dogs gets a puncture.’

I elected to leave it there.  There are some things you just don't ask about in Yandackworroby.

Ant lions

Ants are a necessity we fail to appreciate.  They clean up our gardens, disposing of dead things keeping the garden sweet-smelling.  Ants are generally hard to see, so people often ignore their usefulness.  When they show up around picnics, we resent them, if they get into the house, we hate them, and when they sting us, we loathe them.  Small wonder, then, that most Australian children love the ant lion.

The ant lions are not a tall tale.  They are small predatory insects, the larval stages of lacewings, which prey on ants.  In their adult stages, some lacewings are said to eat aphids, so they are highly regarded by even the most ant-loving adults, or at least those few who know them.

There are ant lions all around the world, but we seem to have more of them in Australia.  The larval ant-lion digs a pit of great cunning, and lurks at the bottom, waiting for an ant to tumble down to its lair.  Once there, the ant will be seized in the ant lion's terrible pincer jaws, and sucked dry.  To do this effectively, the ant lion uses a rather handy little principle of engineering.

Pile some dry sand upon a table, and it will form a cone of a very predictable shape.  Dry sand has a typical ‘angle of rest’, about 30.5 degrees from the horizontal, if the grains are perfectly spherical.  If you shovel dry sand back over your head, you will dig a hole that will slowly get deeper.  If the slope of the sides becomes steeper than the angle of rest, some sand will roll down, making your hole broader and shallower, until the angle of rest is achieved, all around the edges.

If the slope is less than the angle of rest, you can go on deepening your hole until the angle of rest is exceeded.  In the end, either way, you get a beautifully symmetrical conical depression with dry sandy sides, all poised to fall away at the lightest tread.  The ant lion uses its large head like a flicking shovel.

It burrows backwards into the sand, and then flicks the dry grains up and away.  Some fall back into the hole, but soon there is a conical depression which grows until the trap is some 2 cm across.  Then the ant lion digs in at the bottom, with only its pincers in view, waiting for dinner to slide into reach.

An ant, blundering over the edge, starts to slip down the side, dislodging a small avalanche of sand grains as it goes.  This is no problem for the ant, this sort of thing happens all the time in sandy soil.  It starts to scramble laboriously up the slope.  As it goes, it casts more sand down, but slowly it creeps up towards the rim and safety.

But at the bottom of the pit, the ant lion feels the patter of the falling grains, and begins furiously casting sand out of the hole in all directions.  This deepens the hole and undermines the struggling ant from below, and some of the falling grains help to tumble it back down from above.  Occasionally, an ant escapes, but mostly, they fall to the bottom where they are seized and reduced to a husk.  This dried shell is later cast out of the pit with a single toss of the ant lion's powerful head.

Children who have been bitten by ants delight in dropping their tormentors' relatives into the pits of wild or captive ant lions.  In the past, I have collected a wide range of other small insects, and found that ant lions are eclectic diners.  They only eat ants because ants are so much more freely available.  A small weevil, a small sand hopper, even a spider will be dragged down and consumed if it strays within reach.

Ant lions are found wherever there is sandy soil, especially where it is protected from direct rain: under rock ledges, in hollow trees, beside fallen logs, close to buildings, and under any buildings which are on raised piers, a common Australian architectural form.  In really sandy soil, they may even cover open ground with neatly spaced traps.  

All you need to keep ant lions.

The ant populations around our house are increasing now to the highs of high summer, and the ant lion numbers are building up as well.  In a few weeks, I shall catch half a dozen, and take them to school in an ice cream container of sandy soil.  I can think of few better animals to use when introducing students to the hidden world of small insects.  After all, a system is a system, wherever you find it . . .