science – Page 2 – dangermouse.net

Explaining the weather

It rained heavily overnight, but had cleared by morning. It was a warm, sunny day, but there was a chilly breeze coming in off the harbour, which we noticed during a lunch time walk with Scully around the Greenwich peninsula, which involved walking along the water in many places.

At home I upgraded my Mac to MacOS Ventura. I’d been putting this off because I didn’t want to do it on a day where I had Zoom classes, lest something go wrong. Some past upgrades have taken a couple of hours or so, so I set it up to begin before we went for our lunch walk. But it was pretty quick, and done in about 20 minutes with no dramas, and the computer was ready even before we left for the walk.

Much of the day I spent working on my lesson on weather for tomorrow’s science class. I found a really cool diagram showing different cloud types on Wikimedia Commons, which I felt compelled to share here:

It’s available there in much higher resolutions, so click through if you want to see it in detail.

In cooktop news: I made roast vegetables for dinner tonight. I prepared the potatoes (regular and sweet) by parboiling them first with a pinch of baking soda, to roughen up the surface so they absorb the oil and bake nice and crispy. After ten minutes, I wondered why the water wasn’t boiling, only to discover that the gas had been one the whole time without being lit.

This is a very rare occurrence – I can probably count on the fingers of one hand how often I’ve done this in over 20 years of living here, but it was annoying and a bit worrying. One problem is that I can’t smell gas leaks. The ethyl mercaptan that they put in the gas specifically so that people can smell leaks happens to be a chemical that some significant fraction of people are genetically incapable of smelling, and I happen to be one of them. Anyway, the kitchen window was wide open, and I turned on the rangehood as soon as I realised what had happened, and no harm done. But, add another reason on the side of converting to induction cooking.

Oh, another thing I completed today was converting my travel diary from our road trip to Orange back in September into HTML format and uploading it to my website. I added a map of the route and the distances driven (recorded from the car odometer), and you can see the result here. I still need to insert photos to illustrate it… which I’ll get to at some point.

New content today:

Science and Engineering of Photography

This evening I gave my lecture on the Science and Engineering of Photography to the students in the image processing course at the University of Technology Sydney. As I think I mentioned before, this is a special bonus lecture for the students, not part of their coursework, to give them something interesting in their project period during the last 4 weeks of the semester. So I used up most of the first hour of tonight’s three hour time slot with that. There weren’t a lot of students present, but some were listening in on Zoom as well, and several came up to me afterwards to say they liked it.

Earlier today I finished off the last three Outschool classes of the week’s topic on Risk. I assembled a couple of new Irregular Webcomic! strips for this week. And with other random daily stuff like eating lunch and taking Scully for a walk, that ate up the day before I headed into town, where I had some satay chicken and rice for dinner at Spice Alley before the lecture.

The other notable thing about today is that we had over 50 mm of rain, with almost all of it between 6:30 and 9:30 in the morning, so it was really pouring down then. The forecast was 1 to 5 mm! In the next week we’re looking at another 50 mm or so, with thunderstorms indicated almost every day. Yep… after setting a record for wettest year ever, we’re now heading into spring thunderstorm season.

New content today:

That Nobel Prize in Physics

I was chatting with some friends (online) today about the announcement of the Nobel Prize for Physics. They wanted a simple explanation of the work that the prize was awarded for, so I came up with something by paraphrasing some slightly more complex explanations I found.

(A) Realism is the concept that things have definite states, even if nothing interacts with that state. (i.e. the hidden variable interpretation of quantum mechanics – an electron has a spin, even if you haven’t measured it yet.)

(B) Locality is the idea that only nearby things affect you. For distant things to affect you, they need to send something near to you: photons, gravity waves, etc.

What the Nobel laureates proved is that A and B are not both true. (But we don’t know which. A could be false, or B could be false, or both could be false.)

If A is false, then essentially it means the Copenhagen interpretation is true – quantum objects don’t have states until they are observed. If B is false, then it means that quantum entangled particles affect each other even when widely separated, without sending any sort of message between them. We (i.e. quantum physicists) have strongly suspected this for decades, but the Nobel dudes proved it. The first work on this result was way back in 1972, but the final experiment that tidied up the loose ends and cemented it was done in 2015. (I’ll also point out that I haven’t actually studied quantum physics for over 20 years, so I’m possibly missing some details with this simplified explanation.)

I’m strongly reminded that fundamentally we have no idea why the universe behaves like it does. All we can do is make models of what we observe to happen. And some of what we observe is incredibly counter-intuitive and ludicrous.

The main news today here though is the weather. It’s pouring down outside as I type this, and we’re looking at a forecast of 100 mm of rain or more overnight, with heavy seas and winds up to 90 km/h. Most of this weather has come in over western parts of New South Wales, where it’s already causing major flooding issues. It came in mid-afternoon, after a morning that was actually fine and sunny allowing me to get a 2.5k run in.

New content today:

Science and engineering of photography

Today I spent most of the afternoon working on a presentation for the university Image Processing course, to be delivered to the students on 10 October, during the first of their project work face-to-face sessions. The lecturer asked me if I wanted to give a guest lecture as part of the session, and I agreed, thinking I could do one on the Science and Engineering of Photography.

I did an outline of the presentation, then started working on slides. This is the part that takes time, as I have to source images that can be used without violating copyright, or make my own. I got through the camera obscura, pinhole camera, what a lens does, how a camera focuses, circle of confusion, and point spread function. I still need to do slides on convolution, the Fourier convolution theorem, pupil function, optical transfer function, depth-dependent blur, aberrations, camera sensor construction, imaging noise, colour filter arrays, image demosaicing, and other post-capture image processing operations. There’s heaps more that I could go into, but I need to keep it down to about 45 minutes.

The slightly annoying thing is that I had a good presentation on exactly this stuff at work, when I used to work for Canon, which I presented a few times to other staff and to visiting interns and students. But since I made that presentation at work, it was on work machines, and I couldn’t bring it home with me. But at least after I do this, I’ll have one handy for future use. I could even adapt it for use to teach kids about how cameras work on Outschool.

This evening I made a special dinner. I’ve always liked fried cauliflower, but it’s a bit of a mess to make. But today we had most of a cauliflower left over as the remaining vegetable before grocery shopping tomorrow, so I decided to go for it. I cut it into florets, coated them in flour, egg wash, and breadcrumbs, and shallow fried them in a pan until golden brown. I served them with a mix-it-yourself set of sauce ingredients: yoghurt, tahini, sriracha, chutney, and mayonnaise. It turned out great! (Except I left a couple of pieces a bit too long before turning them and produced a bit of smoke, but fortunately it dissipated without setting the alarm off.)

New content today:

Trekking north for a day

Today my wife had a day off work, and my only ethics class was from 9am, so I was done by 10 o’clock. We decided to take advantage by going out for the day. We took Scully and we drove up to the northern beaches suburbs, as far as Avalon Beach, almost an hour’s drive.

There we stopped at Oliver’s Pies to get some lunch. We took them across the road to the large park there to let Scully run around while we ate, and after finishing I tossed a ball for her to chase for a while. Then we went for a walk. I wanted to do a path through Bangalley Headland Reserve, and we walked a few blocks to where the track started, but we discovered that dogs were prohibited on the track. So unfortunately we had to return to the car.

Instead, we decided to go to the shopping centre at Avalon and sit at a cafe for a bit so my wife could get some coffee. I got a nutty chocolate treat as well while there, and we discussed what else to do. We decided to stop off at Warriewood Wetlands on the way home, which is a great spot to walk around and spot birds. I had my camera with me, and managed to get a few shots, although we were walking rather than waiting patiently for opportunities.

Willie wagtail:

Australasian grebe:

Dusky moorhen:

We also saw Eurasian coots, superb fairywrens, silvereyes, Pacific black ducks, and we heard plenty of bell miners, but those guys are almost impossible to spot.

In other news, I got a minor scrape on my left hand while cooking dinner and put a band-aid on it. Then later while washing up, I didn’t want to get my left hand wet, so I swapped hands and held the pots in my left hand while scrubbing them with the dishcloth in my right hand. This felt so weird and uncoordinated! I was curious and asked my friends on our group chat what hands they use to wash dishes, and they all said that they normally hold the item in their left hand and scrub it with the right. My wife said the same thing.

This isn’t the first time that I’ve discovered that I do something the opposite way to other right-handed people. I use my left hand to eat finger food (I just confirmed my friends use their right hands). I know I ride push scooters and skateboards the same way as left-handed people. I tie my shoelaces using a mirror image sequence of moves to right-handed people I’ve watched. But I consider myself right-handed. I write with my right hand, I throw right-handed, I play sports like tennis, cricket, golf right handed.

I was just now searching casually on Google for if this is a known thing – right-handed people doing a whole bunch of things in a left-handed way. And it turns out there’s a term for it! Cross-dominance! I’d never heard of this before, but yes, that’s me. Huh. So I just learnt a thing about myself.

New content today:

Evolutionary Sunday

Today I had another science lesson online with the girl who has been taking those intermittently. Last time we began talking about evolution, and today was the second half of that topic. I prepared some slides showing the Galapagos Islands, Charles Darwin, finch beaks, hybridisation (lions and tigers crossbreeding to produce ligers), induced speciation in fruit flies, evolution of apes, and whales, and horses, and something about the evolution of antibiotic resistance in bacteria. It was a fun class and the student seemed to really enjoy it.

The weather here has turned slightly chilly as we get deep into autumn and start thinking about winter. We’ve had nice sunny days, although with some overnight rain just to keep things damp, but the maximum temperatures have been in the low 20s Celsius, which is noticeably cooler than the past months. And the nights have been getting quite chilly, down around 14°C, which feels like a big change from the overnight lows of 18°C we were getting a few weeks ago. 18°C is comfortable – I was taking Scully out around 10pm for her final toilet in just shorts and a T-shirt, but now I’m having to wear long pants and a jacket to do it.

We took Scully for another walk and ball chasing episode just after lunch, this time down to the nearest ferry wharf and the secluded adjacent park. The park is in a bowl-shaped hollow leading down to the water, so it took some care throwing the tennis ball so that it wouldn’t roll down into the harbour.

Um. I guess it wasn’t an especially interesting day, apart from thinking about evolution a bit.

New content today:

Comic making blur

Today was very busy. I had ethics classes at 9 and 10am, followed by going for my daily run, lunch, and then getting stuck into making another week’s worth of Irregular Webcomic! strips. I wrote 5 strips, photographed them, assembled them, and wrote annotations for them all in just a few hours. By the time I was done I needed a break, because I’d been working solidly the whole time.

This evening I had an ethics extension class, followed by a class of my human vision science lesson. One of the new kids who joined ethics last week found this class and enrolled in it, and he was really keen and enjoyed it a lot. At the end he said he learnt a lot and it was really interesting, so that’s good! And the parent gave me a 5 star review. I should schedule this class more often – it was a lot easier to teach it this time than the previous times, I think because I now have a lot more experience doing this, and felt a lot more relaxed with the material and using Zoom. (I hadn’t taught this class for almost a year, and was only prompted to schedule more classes because Outschool threatened to delist it.)

I cut a pineapple for dessert tonight. We haven’t had a pineapple for some time, and I saw them in the supermarket and just felt like one last time i went shopping. I like to have pieces sprinkled with cinnamon – it really adds something.

Oh, and I updated my desktop machine to MacOS Monterey tonight too. I’ve bene putting this off because previous updates have taken hours to install and I’m never really confident that it’ll work, but this one was relatively painless, and took barely an hour.

New content today:

Ethics of data; and body systems

Today I got in a good chunk of work on the university data engineering course, writing an outline of a presentation on the ethics of data science. I also went over the lecturer’s notes for the lecture on data types and some exercises he’d prepared. We’re having a Zoom meeting tomorrow to discuss progress and plan out the rest of the time between now and the beginning of the course in late February.

The rest of the afternoon I spent assembling slides for tonight’s private Outschool science lesson. Today we’re covering body systems – or at least getting started on it. I suspect I have enough material to last for two weeks.

For dinner tonight I made calzones – spinach and ricotta, with a tomato/onion/garlic sauce to spoon over the top.

New content today:

Starting biology

The Christmas break is over. My wife got up early this morning, and so did I. She’s working from home again, due to COVID, so we’re back into that routine again.

I spent much of the day making slides for tonight’s resumption of online science classes with my one-on-one student. Last year we started with physics, going through atomic theory, electromagnetism, and light. I thought we could start off the new year by changing fields into biology. So today I made a presentation on cells. I found a fantastic collection of public domain microscope images and videos of cells on Flickr, by the Berkshire Community College Bioscience Image Library. And an incredible collection of public domain biology diagrams by one very generous Wikimedia Commons contributor. Together they made a great presentation.

New content today:

Clearing a memory backlog

Two things that happened in the past few days, but which I forgot about when writing here:

1. Yesterday when I was out with my wife walking Scully in the early evening, we were enjoying the quite strong breeze that was cooling down the heat of the day. I didn’t realise quite how strong the wind had become until we happened across a scene on the street: Two young men were examining where a large tree branch had fallen onto the street, blocking it. It was a eucalyptus branch, and pretty substantial – maybe 4 metres long and the diameter of a dinner plate at the base end where it had splintered off the tree above. It was fortunate that nobody had been under it when it fell, as it could have been very dangerous.

But unfortunately the car belonging to one of the men was under it at the time. The branch had caught it at a glancing angle on the side, smashing the tail light and causing some significant dents and scrapes in the bodywork. The guys were maybe teenagers, and one of them looked at us as we approached. They didn’t seem to know what to do, and one asked me who would be liable for the damage to his car – would it be the local council? I answered that I didn’t think anyone would be liable, and the damage would need to be covered by his insurance.

We left then trying to pull the branch away from the car, but they weren’t having much luck as it was pretty heavy. This morning when I walked past the same spot, I saw that the State Emergency Service had come to chop the branch into firewood sized chunks and has piled it up by the side of the street, with emergency tape around it.

2. A few nights ago, I think it was the night of 30 December, I took Scully out for her pre-bedtime toilet. As I always do, I gaze up at the stars (assuming a cloud-free night). Orion is prominent in the northern sky at the moment, with red Betelgeuse at the bottom, and the bright blue of Sirius in Canis Major trailing it to the right. (This is upside down compared to what people in the northern hemisphere see, of course.)

Anyway, I was looking up at Orion, when I saw a very bright streak of light flash rapidly from east to west, just below the constellation. It was a meteor. I see them occasionally when taking Scully out, but this was one of the brightest I’ve seen. So that was pretty cool.

Today, I spent time assembling and writing annotations for Irregular Webcomic! strips for the coming week. I got stuck into some mathematics for one of them, so it took some time. I even had to break out Matlab to do some calculations.

For dinner I made quiche, with home made shortcrust pastry. Previously I’d been rolling the pastry cold from the fridge, and wondering why it always cracked around the edges. Searching the net turned up some advice to let it warm up a bit before rolling, and that seemed to help a fair bit, so I’ll do that from now on.

New content today: