In silico mobile

The other day I talked a about the physics involved in mobiles. I said I wanted to build a bigger and simpler one. I don't actually have time for that, but I can simulate it:

The same one with perspective:

I'm afraid the gifs don't always load properly, maybe they are a bit heavy.

Mobile physics

About a year ago Gabi gave me some vintage flying dinosaur toys. Since then, I've been meaning to do something with those. They are not sufficiently nice as to display them by themselves, but they look really good when they are together, that's why we said "let's build a mobile!". It's been more of a child-bedroom mobile than an Alexander Calder's, but hey, it's our first time.

We only have 4 dinosaurs, which is actually the complete collection. We got some wood sticks from the dolar store, and thread.

The objects (dinosaurs) are suspended in a 10 cm string, and the lower level suspends from the double of that (20 cm). Those distances can change depending on the size of the object you hang, the length of the string doesn't affect the balancing, but it's important that the objects don't bump into each other. The rod length can change as wished, that won't affect the balance either (it's only the ratio between each side of the lever what matters, see below.)

It's really great how many configurations such a simple object has, and more importantly, governed by chaotic dynamics!

While I was building the craft, I couldn't help thinking about the physics it envolves. It is a quite simple problem, very easy to model following Archimedes "Give me a place to stand, and I shall move the Earth with it".

We enumerate each level of the mobile as n, the mass of the rod is M, the length of the rod is L, and the mass of the object is m. Here we consider that the strings are massless and that each rod and each object have the same weight.

The small side of the rod (distance from the rod tip to the string that it hangs from) Ls of the nth level will have length:

Therefore it behaves as 1/n. Below there is a Ls/L plot and a scheme of an ideal m=M mobile plotted using Python.

That last scheme made me want to build a very minimal mobile, exactly the same as this one.

Whiteboard

So, I got back to university for graduate school. And it's cool how everything feels totally different from the boring bachelor's degree. After discussing lots of physics with colleagues and my supervisor, I realized that whiteboards are exactly where the magic happens. That's why I got obsessed with getting a nice whiteboard for home.

I looked at many options, I was about to spend $60 in whiteboard from Staples, but since we were in front of IKEA, we got in there to see what do we find. They sell an actual whiteboard which looks nice (even though I would need like 2 of those to fit in some formulas).

However, we bumped into a 70 x 100 cm aluminium picture frame for $15 that is just perfect. You simply draw on the glass, and, even after many days, it's extremely easy to erase.

I use it a lot, and I actually own a bunch of different markers for the sake of good science!

Québec

Pau went to a Genetics conference close to Montreal and I tagged along for a short vacation. We spent four days at the hotel in an amazing room with views to a frozen lake. It was great, although Pau had to work most of the time. He presented a poster and a short talk and I couldn't be more proud.

After the conference we spent the rest of the week in Montreal, getting to know a tiny little bit of the city. Right in the first hours a couple passed by us on monocycles. We were definitely in the city of Cirque du Soleil and Just for Laughs. Not really our kind of entertainment...

We rented a beautiful loft on AirBnb. Beautiful on the inside, that is. The building itself was really squatty and noisy, but it was fun and a lot more private and cheaper than a hotel. I was prepared for all the cold weather I expected from april in Quebec, but luckily it was sunny and warm every single day we were there.

I don't want to say we were disappointed with the city because we did see some really nice places (like old montreal, one nice neighbourhood with lots of cafes and bookshops and this art instalation with musical swings), but I admit I was expecting a lot more. French really is the first (and pretty much the only) language there, which is awesome but made me feel a bit weird at times, having to explain I don't speak french everywhere. It was one of my first trips, and definitely the longest, to a place where I don't speak the language at all.

I'm probably spoiled by the way things are in Vancouver, because I felt the city to be a little bit decadent and dirty. There were abandoned buildings right downtown and a lot of potholes on the streets and sidewalks. It was also weird to see a lot of strip tease and sex- related shops everywhere. The shop's windows were also dark, dirty and decadent... I wish we taken more pictures to illustrate it all. We're still not very good in the picture taking department.

As for the culinary adventures, there was not much on the conference phase since we were stranded on the hotel eating buffet food, but in Montreal we tried Shabu Shabu, which is a sort of Japanese fondue, that has nothing fondue-y or tasty about it, unfortunately, because the idea seemed really fun. It's a pot of vegetable stock placed on top of an electric stove to which you add tofu and vegetables to cook, dip them on different sauces and much, while sipping on the vegetable infused stock. It all ended up tasting next to nothing with very strong hints of a foul algae. Definitely a one time thing.

While in Chinatown we bought some fake meats made with shiitake mushroom to cook at home that were really tasty. On our last day we had veggie burgers and poutine at a very very cute place on Mile End, that nice neighbourhood, finishing up with a sugar and lemon crepe and coffee for desert.

...

This is Pau taking over. It was a very lucky coincidence the that the first time we're in Quebec my best friend's band from Barcelona is playing there. We got to spend almost 24 hours together which fuelled me up with social happiness enough to survive until we next time visit Barcelona. Plus we went to an awesome punk show with Crazy Spirit, Glam and Una Bèstia Incontrolable. Pretty preeeetty cool altogether.

Just an ordinary French-Canadian punk car, I guess.

Glam.

Crazy Spirit.

Punk house breakfast.

Last but not least, we bought a totally awesome vegan shitake mushroom lamb in a Chinatown supermarket and we cooked the best of meals. Too bad that we didn't take any pictures of neither the frozen package nor the final outcome.