Sergey Pavlov

Although this is a bio class, I was really interested in observing something nonliving (that had once been alive) under the microscope: paper. Looking directly at a piece of paper with out Foldscopes would be difficult – even at a thickness of only 1/10 of a mm it simply blocks out too much light – but I thought it might be possible to observe the edge of a piece of paper.


 Indeed, after placing two pieces of paper (normal and carbon copy) on a slide and covering them with a glass coverslip, and a bit of panning and fiddling with the focus ramp, an otherworldly scene came into view.

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 <img alt="IMG_2444" class="wp-image-125408 gcloudimg" data-attachment-id="125408" data-comments-opened="1" data-image-meta='{"aperture":"2.2","credit":"","camera":"iPhone 6","caption":"","created_timestamp":"1549805647","copyright":"","focal_length":"4.15","iso":"32","shutter_speed":"0.0035460992907801","title":"","orientation":"6"}' data-image-title="IMG_2444" height="452" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_125407/IMG_2444.jpg" width="339"/>
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 The paper fibers, weaving and twisting around each other, looked remarkably like matted human hairs! It was pretty surreal to pan along the edge of the paper, looking at the different patterns that appeared. I was interested as to the composition of these fibers, and it turns out that in the process of pulping during papermaking, the cellulose in wood is separated from lignin, which generally doesn’t go into paper, since it deteriorates over time. Most trees are slightly less than 50% cellulose, so the goal of pulping is to isolate it from other impurities in the tree. It’s this cellulose that forms the long polysaccharide fibers in paper pictured above, through covalent bonding between the monosaccharides and hydrogen bonding between adjacent chains. This was the edge of the normal paper that had been ripped by hand, so next I decided to take a look at the artificially cut edge to see how different it might appear.

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 <img alt="IMG_2449" class="wp-image-125409 gcloudimg" data-attachment-id="125409" data-comments-opened="1" data-image-meta='{"aperture":"2.2","credit":"","camera":"iPhone 6","caption":"","created_timestamp":"1549806047","copyright":"","focal_length":"4.15","iso":"32","shutter_speed":"0.00187265917603","title":"","orientation":"6"}' data-image-title="IMG_2449" height="408" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_125407/IMG_2449.jpg" width="306"/>
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 Very different! Although there were plenty of imperfections on this side of the paper, it was much, much smoother than the ripped side. It’s surprising to think that this flimsy-looking edge can cut through human skin! Next, I took a look at the ripped edge and cut edge of carbon-copy paper.

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 <img alt="IMG_2461" class="wp-image-125411 gcloudimg" data-attachment-id="125411" data-comments-opened="1" data-image-meta='{"aperture":"2.2","credit":"","camera":"iPhone 6","caption":"","created_timestamp":"1549806576","copyright":"","focal_length":"4.15","iso":"32","shutter_speed":"0.0083333333333333","title":"","orientation":"6"}' data-image-title="IMG_2461" height="421" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_125407/IMG_2461.jpg" width="421"/>
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 This is the corner of the paper, so it shows both edges next to each other for a sense of scale. It’s clear that ripping allows for the fibers to become separated from each other and actually observable, while cutting during papermaking keeps the fibers relatively compact. There didn’t seem to be much of a difference between the two types of paper, although the fibers in the normal paper did seem to be a bit longer and messier than the ones in the carbon-copy. Although, paper might not be alive, it’s a world on its own that’s fascinating to observe!

Paper: Bio 60_2019

I was searching for an idea for my second Foldscope post, and one fell right into my cup of tea: a small insect that had evidently drowned in the little pool of water left overnight in the cup. I wasn’t sure what it was, but I planned to examine its body parts to see if it was possible to arrive at an identification.


 After fishing the insect out of my cup, I placed it on a glass slide using tweezers and detached a couple body parts – two antennae and a few legs – and plated two of them by pipeting a couple drops of water onto the slide and placing a glass coverslip on top. Due to the small size of the insect, I wasn’t actually sure if the second body part I had plated was a leg or an antenna! The only way to find out was to take a look with the Foldscope.


 Looking at the first body part (antenna), I saw clear segmentation, with each brown segment coated with many small bristles. Also, there was a strange, dark casing surrounding the entire antenna, which I couldn’t seem to find on any photos I saw online. Could this possibly be the edge of the droplet of water being repelled from the surface of the antenna?

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 <img alt="IMG_2511" class="wp-image-130534 gcloudimg" data-attachment-id="130534" data-comments-opened="1" data-image-meta='{"aperture":"2.2","credit":"","camera":"iPhone 6","caption":"","created_timestamp":"1551013863","copyright":"","focal_length":"4.15","iso":"32","shutter_speed":"0.00063211125158028","title":"","orientation":"6"}' data-image-title="IMG_2511" height="439" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_130522/IMG_2511.jpg" width="329"/>
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 The segments didn’t seem to get much smaller towards either end of the antenna, but did get a bit lengthier and ended with a different-colored segment, possibly what the insect uses for sensing. In my opinion, this antenna looks most like the moniliform antenna found in some beetles and termites, but I could very well be wrong: https://thedragonflywoman.com/2011/04/15/insect-antennae-part-1/. Are there any entomologists who could perhaps weigh in?

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 <img alt="IMG_2507" class="wp-image-130535 gcloudimg" data-attachment-id="130535" data-comments-opened="1" data-image-meta='{"aperture":"2.2","credit":"","camera":"iPhone 6","caption":"","created_timestamp":"1551013731","copyright":"","focal_length":"4.15","iso":"32","shutter_speed":"0.00045495905368517","title":"","orientation":"6"}' data-image-title="IMG_2507" height="491" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_130522/IMG_2507.jpg" width="368"/>
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 Looking at the other body part, I saw that it looked nearly identical to the first antennae, so I guessed that it was one also. Again, there was the mysterious casing, which I thought to be a result of the repulsion between the water and the antenna.

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 <img alt="IMG_2510" class="wp-image-130541 gcloudimg" data-attachment-id="130541" data-comments-opened="1" data-image-meta='{"aperture":"2.2","credit":"","camera":"iPhone 6","caption":"","created_timestamp":"1551013821","copyright":"","focal_length":"4.15","iso":"32","shutter_speed":"0.00058105752469494","title":"","orientation":"6"}' data-image-title="IMG_2510" height="396" src="https://storage.googleapis.com/microcosmosdelta.appspot.com/images/transfer_130522/IMG_2510.jpg" width="297"/>
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 In the end, I dropped the bug on the floor (oops) and couldn’t find it again, so I didn’t get a chance to look at its head, its legs, or its wings to give more hints towards its identity. What I learned from this observation was the astounding variety of insect antennae types, each corresponding to a different lineage of insects, and that insect ID is much more difficult than I had expected.

Sergey Pavlov

Earth

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Paper: Bio 60_2019

Bug’s Body Parts: Bio60_2019

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