Fire day

The main thing about today was not anything I did, but the weather and the resulting fires across the Eastern parts of Australia. We’ve had out-of-control bushfires burning in various parts of New South Wales and Queensland since the weekend, and today’s weather was very hot and windy. The combination resulted in declarations of (a) total fire bans across all of NSW and Queensland, (b) “catastrophic” fire conditions in the Sydney and surrounding regions – the first time this warning level has ever been issued for Sydney, and (c) an official state of emergency in NSW from today, for the next seven days.

Over the past few days, several hundred homes have been destroyed by fire, and a handful of people have been killed by the fires. We expected the worst today, as temperature rose to 37°C in Sydney, and hotter in some rural areas, with very low humidity and high winds. Throughout the day as the temperature climbed, I kept up with the news, hoping not to hear of further tragedies.

While this was happening, I spent the morning back at the school I went to yesterday, working with a couple of the kids in the Science Club, to prepare a short slideshow presentation of the work we’ve been doing all year. The older kids in the Science Club are going to present the experiments we’ve been doing to the whole school at an assembly in a couple of weeks. They have a 15 minute slot, so I made sure to keep things tight, and helped them write a script to read from.

I was home around lunch time, and then began work on getting a result from our solar shadow measuring experiment, that the kids have been working on since May – recording the length of a shadow each day as the sun moves.

Later I went out with my wife and Scully to the pet shop, for some exercise, since it was a much cooler option that going to the park. We walked over to the hardware store as well, and a couple of other places nearby to buy a few odds and ends. Scully enjoys going to the pet shop, as there are so many interesting things to smell. But she was getting restless again early this evening, so I braved the heat and took her to the nearest park to chase a ball around for a while until she got exhausted. While we did this, I could see the smoke from the bushfires around Sydney drifting across the sky.

Scully and the bushfire smoke

(This photo was walking home, not at the park.)

New content today:

School science visit

Today was my visit to the primary school where I talk to the kids about science stuff. I had three separate session with kindergarten, Year 1, and Year 2. As mentioned on Saturday, I presented a talk on dinosaurs for the K and 1 kids. I included a bunch of photos of fossils with feathers, and showed them what feathered dinosaurs look like. The conclusion was that only some of the dinosaurs died out a long time ago, but some of them – the birds – never died out at all, and are still around us today. They really enjoyed it, so that was good.

With the Year 2 class I did a general Q&A. Some of the questions they asked included:

  • Where did the Earth’s water come from?
  • Why did the dinosaurs die out?
  • Where did humans come from?
  • Why isn’t Pluto a planet any more?
  • How do you make a black hole?
  • Does the Earth run on coal? – I talked a bit about what coal is, and how it’s used to make electricity, and how it adds carbon dioxide to the atmosphere, and how this is a bad thing because it’s causing climate change, but how hard it is to stop using it because people need the electricity.
  • How do potions work? – This was fun. I talked a little bit about how potions are fictional and don’t really work like in books and movies, and also a bit about alchemy and how alchemists used to believe they could make magical potions. By mixing things together and learning how they worked, they actually invented the science of chemistry instead.

Besides these three large groups, I also had Science Club with the group of 13 students I’ve been working with all year. It’s really quite a strange thing to be left in charge of 13 kids aged 7 to 10, with no other supervision, and be allowed to do science experiments with them (not on them!). Today I brewed up a pH indicator liquid by mixing hot water and shredded red cabbage. Within half an hour (during which I went over the results of our previous laser experiment), we had a rich purple liquid strained off. I gave each child a plastic cup and one of the chemicals I’d brought in. Then we added the cabbage liquid to each and watched them change colours:

pH experiment

pH experiment

From left to right around the table, the kids had: baking soda, soda water, white wine, bleach, apple juice, cream of tartar, lemonade (i.e. Sprite/7-Up for the Americans), vinegar, lemon juice, and ammonia solution. The bleach and ammonia I gave to the oldest kids, and made them wear rubber gloves for safety. And you can see the different colours they produced. Here’s a shot with them arranged in order of pH:

pH experiment

After establishing a sequence of colours for the chemicals, we tried mixing some of them. Adding baking soda to the vinegar made it (1) fizz up, (2) change colour, becoming a deep blue-purple. We mixed a few other things together, and the kids tried to predict the resulting colours (without much success). We established that mixing acids and bases tends to neutralise the result, making it closer to the original neutral purple colour. I made absolutely sure we didn’t mix the ammonia and bleach – I didn’t want to be generating chlorine gas!

This pretty much took up my whole day, as it took a while to drive home in the late afternoon traffic. And I was exhausted! I don’t know how school teachers do this every single day!

New content today:

Science Saturday

Besides the usual bathroom cleaning, I dedicated much of today to Science! I finished writing that 100 Proofs article I’ve been mentioning.

And I planned out what I’ll be doing with the school children on my next STEM Professionals in Schools visit on Monday. I wanted to do a Q&A session with all the classes, because it’s minimal preparation for me, but my contact said the kindergarten and Year 1 teachers requested me to do a presentation, because their kids are too young to be able to come up with sensible and meaningful questions. [It’s true – last time they got fixated on asking me “how many X are there?”, for X=(cats, animals, fish, bones, trees, etc).] SO I went through my old slides and found one I did on dinosaurs 5 years ago – so none of the younger kids will have seen that one. I refreshed myself on what was in the slides so I can talk about it on Monday.

And for Science Club I planned a new experiment. We’re going to make pH indicator using red cabbage, and then test various household chemicals. The usual suspects like lemon juice, vinegar, baking soda, etc. Which meant I had to draw up a shopping list. I’ll have to go shopping tomorrow for everything I need.

Oh, and I spent a bunch of time making tomorrow night’s Darths & Droids strip, following the writing session yesterday.

And now, it’s late… time for bed!

New content today:

Summery Friday

It was hot today: 33.5°C in Sydney. Summer has definitely arrived early. Not only is it unusually warm, but much of south-east Australia is in the worst drought in recorded history. Several towns are in imminent danger of their water supplies running completely dry. Dubbo, a large regional town announced upgrading to Level 4 water restrictions this week, which makes showers longer than 5 minutes illegal and all watering of lawns illegal. Sydney is currently on Level 1 water restrictions but it probably won’t be long before we start climbing the levels too.

Another big fear is bushfires. As the weather heats up towards summer, the dry vegetation all over south-eastern Australia is going to be at great risk. It’s been a couple of decades since the last disastrous level fires with tens of lives lost, but everyone is nervous about this summer.

I stayed in out of the heat today and tended to a stack of odd jobs I had piled up – literally – on my desk. I sorted through the pile of papers and paid some bills, filed some documents, organised things needed for my upcoming trip to Germany, and collated data collected from the laser experiment during my last school science visit. I calculated the wavelengths of the lasers we used from the interference patterns the kids traced and put it into a slideshow to show them on my next visit. It turned out that their sketching skills were not great, with some individual wavelengths being out by almost 100 nanometres, but luckily the averages of three measurements made with different slit configurations turned out to be within 9 nm (or under 2%) in each case. A good result, if honestly more by luck than careful measurement!

For dinner tonight my wife and I went to a French crepe place that we discovered recently. It’s run by four French immigrants who loved everything about Australia, except for the fact that they couldn’t find good crepes anywhere, so they decided to start their own restaurant. Both the savoury galettes and dessert crepes are really good, washed down with imported French cider. And outdoor seating, so Scully is allowed to sit with us.

New content today:

Laser day

Today was my visit to the primary school to talk to the older classes about the solar system, and to supervise my Science Club class while we did experiments with laser diffraction. We measured the diffraction patterns of red, blue, and green laser light through double slits, replicating Young’s seminal experiment which established that light had the properties of waves. We ran out of time to do all of the calculations, but very quickly I got a rough figure of 620 nanometres for the wavelength of the red laser (which actually has a wavelength of 632.8 nm, so we got pretty close). Over the next while I’ll refine the measurements and calculate the other wavelengths too.

It was rainy today in Sydney. At least on the coast. It was dry as I drove towards the school, which is near the coast, and as I came down the hill from the plateau to the coastal strip, it began raining, and was really heavy by the time I got to the school. Unfortunately, we need the rain inland, where the dams are for our water supply.

New content today:

Cathedral framed

Prep for Science Club

Today I did final preparations for Science Club at the school tomorrow. I checked all the lasers, got spare batteries, and copied the dimensions of the slits in the slides to a sheet of paper so I can read them easily during the experiment, rather than having to squint at tiny print. The blue laser is cool, but it’s difficult to see the diffraction patterns after passing through the slits – I suspect because our eyes aren’t nearly as sensitive to blue as they are to green and red. Hopefully it’ll work better in the dark library at the school.

This morning I did some grocery shopping. I do almost all the cooking at home and I like browsing around the vegetables looking for interesting things to cook with. Corn cobs were on special today, so I bought a couple. Not sure what I’ll make with them yet. Probably just boil them up and eat them on the cob, with something else on the side to fill out the meal. I also bought a chicken breast, but that’s for Scully. We don’t really cook meat at home, except on very rare occasions. (I don’t cook it very rare…)

My wife had her Rock School end-of-term concert this afternoon. Normally I attend in person, but today they were live streaming the concert and she was only singing lead on three songs, so I stayed home to get some other things done while watching the stream. I had to clean up a few messy piles of stuff that I’ve had eating up space on the dining table for a while.

For dinner tonight I made pasta with pumpkin, feta, walnuts, and chilli in burnt butter. It’s one of our favourite ways to have pasta – the nuts add a nice crunch which creates the range of textures with the soft pumpkin chunks, creamy feta, and al dente pasta. (Last night I made a frittata with potatoes, broccolini, caramelised leeks with balsamic vinegar and garlic, and of course eggs. It turned out pretty good, I thought. Taking a solid half hour to caramelise the leeks before doing anything else was worth it.)

The other thing I did today was process and upload a few more photos from my trip to Portugal back in May. Going through travel photos always takes a while, since I take a lot of photos! I started going through photos after our arrival in Porto. Porto is built on very hilly terrain:

Porto is on a hill

Here’s the Igreja de Santo Ildefonso, a spectacular church with azulejo tiles on the front edifice.

Igreja de Santo Ildefonso

New content today:

Cleaning and science

Saturday is housecleaning day, and I did more than normal today, with a thorough vacuuming and dusting, which ate up most of the morning. Then I wrote up the results of the pendulum/gravity experiment I did with my primary school Science Club class a couple of weeks ago, in preparation for my next visit on Monday. I made slides to show the kids, and I also wrote it up over on 100 Proofs that the Earth is a Globe.

In the afternoon, my wife and I took Scully out for some exercise. We found a new park to try out, about 10 minutes drive away. We like going to different places, so Scully can explore. She had a good time running around the grass, meeting another dog there, and chasing a brushturkey and some ducks – I think they were Australian wood ducks.

At the park we saw an amazing cubby house that someone had in their back yard for the kids. The yard backed directly onto the park, with no fence, so we had a good view of it.

Cubby house

New content today:

Lasers!

I have lasers! Today I went to Sydney University and borrowed some of thee lab equipment from the Physics labs, for use in my primary school visit on Monday. I assured the lab technician who organised the loan that I wasn’t going to be borrowing stuff frequently, but he was delighted that I was borrowing it, and said I could have equipment whenever I wanted it. He said it was good that I was doing science with school children, and he encouraged me to get them interested in science. So that was good!

He gave me three lasers, one red, one blue, and one green, as well as a selection of slides with single slits, double slits, triple slits, apertures of various shapes, and a transmission diffraction grating. I’ll have to swot up on my interference and diffraction theory over the weekend so I can run the experiment smoothly and get the kids at school to calculate the wavelengths of the three different lasers during the lesson. It should be fun!

I also caught up with my Ph.D. supervisor while visiting the Physics Department. He’s semi-retired now, but still appears to be working virtually full time, both teaching in the labs and doing research into fast radio bursts with the Molonglo Observatory Synthesis Telescope (the telescope I used to do my Physics Honours project back in the day). He’s the author “R. W. Hunstead” on this 2017 discovery paper.

New content today:

Winter blast

Today was cold and windy. It really felt like winter for once. I went out for lunch and the sky even had clouds in it! They were pretty thick and grey in fact, and I thought it might rain, but the promise of any precipitation turned out to be false.

Besides being a very warm winter, it’s also been extremely dry. We’ve had just 3 mm of rainfall so far this August, and Sydney’s average August rainfall is 80.3 mm. In July we had 43 mm of rain, mostly loaded into the first week, while the July average is 95.7 mm. So we’ve basically had 6 weeks with almost no rain at all. The news tonight reported that Sydney’s water supply dam level is now below 50% – the last time this happened was 15 years ago.

Besides the false promise of rain, the weather was pretty wild. I took Scully out to the dog park, and even though I rugged up in a jumper (sweater for the Americans) and a windproof jacket, it was still nastily cold with the wind blowing off the harbour. While there and chatting with some of the other dog owners, we heard a big crack, and we turned to see that a branch had fallen off the huge Moreton Bay fig tree that we were sitting/standing under (there are wooden benches there for sitting, which many of the owners do). Fortunately, it was on the far side of the tree, and didn’t land on any of us or our dogs. It landed on the street beside the park, narrowly missing someone’s parked car (lucky it didn’t land on that too).

A few of us dragged the branch off the street to clear it for traffic, and I took a photo. It’s not a huge branch, but would certainly have caused an injury if it had fallen on someone, or dented the roof or smashed the windscreen of a car. You can see it’s longer than a car, and it was fairly hefty.

Fallen branch

That’s Scully on the right, with the red doggy-jumper. Next to her is Monty, a chihuahua-Jack Russell cross. Up on the street is Scout, a west highland white terrier. As you can see, all the dogs are rugged up for the winter weather!

Also today I contacted Sydney University again to arrange to borrow some lasers and diffraction slits for my next visit to the school where I teach my Science Club class. We’re going to measure the wavelengths of different colours of light! I’ll go in tomorrow to pick them up.

New content today:

School science visit

Today was the big day! I spent the day at a local primary school, talking to the kindergarten to Year 2 classes about the solar system. I got back in 2 weeks to do the Year 3 to 6 classes. It’s Science Week, so some of the kids also set up tables in the playground at recess to show off the science experiments they’ve been doing in class recently. There were crystals being grown, model boats being floated and loaded with weights until they sank, electronic kits being used to build various gadgets, and the Science Club showed off some results from the bacteria growing experiment I did with them earlier this year.

Growing crystals

Also today I spent an hour and a half with the Science Club students. We went through the results of the colour naming experiment, which I reported on over on 100 Proofs not long ago. Then we performed a new experiment, to measure the strength of Earth’s gravity using a pendulum. We varied the mass of the pendulum, the distance it swung, and the length of the string. We took a whole bunch of measurements, and I’ll analyse them and calculate the results for next time we meet in two weeks.

Oh, and we also made another measurement of the length of a vertical stick’s shadow at midday, as part of our ongoing measurement of the size of the Earth using the geometry of the Earth’s orbit.

Measuring shadows

It was a busy day, and I didn’t have time for much else other than relaxing afterwards! The teachers at this school work very hard for their students, and I’m constantly amazed how much work they do and how demanding it is. School teachers are one of the most under-appreciated professions, easily.