Slinkies and Dinoroars

I was going to make good on my promise to give some Python tips for this blog, but after reading through all my lab python notes I realised that there are better links from the lab website (and now even pre-course material to complete before the start of labs.) Damn it. Oh well—I think that is a good idea and am glad Imperial have beat me to it 😛

You probably know this already but you can find all this lovely information on the first year laboratory and computing website and the whole of the course is actually on Blackboard, including a load of links on where to download python and places to get tutorials and everything.

So this is a non-existent blog really, except to say that you shouldn’t be worried about computing—I am by no means a natural (haha understatement), and my code is the least elegant and practical thing you will probably ever see, but I still managed to get above seventy per cent in both my python labs by basically bashing my head against it until it started to trickle in. It’s actually quite fun, as I would tell people after moaning about it constantly for the whole lab cycle. (It is though, I promise!)

As I think I have mentioned before, my year was the first to do the course, and they are very keen to get feedback and improve it, so being trial year three should be spiffing!

For my first year lab project, my lab partner and I did the Physics of slinkies, which was so much fun and involved us trying to simulate the joyful springs in Python. I still have the video we showed at the presentation so here it is as a wonderful example of what you too will be able to program by next year 😛

I am sorry for the awful slinky advert soundtrack by the way. I only have the final, recorded version of the video so I can’t take that off… I recommend turning down your sound. It’s also quite a slow video, because we were meant to be explaining to people through it 😛

The reason we got so obsessed with falling slinkies at the start of the video was because the top end falls while the bottom remains stationary right up until the top end collapses on top of it. This means if you were sitting in the bottom of the falling slinky you could levitate, for a bit (until the slinky collapsed and hit you).

The base of the slinky remains stationary until the above coils have collided simply because there is still an upward force due to the tension in the spring above acting on it, that does not change until the above coil is pushed downwards by the one above it.This continues on to the top of the slinky, and since the top coil does not fall infinitely fast, it takes time for the wave of coils falling to propagate down the slinky.


This is actually a good demonstration to do to someone who thinks that if you poked someone with a pole a light-year long you could prevent murders in the past or whatever. Well, a good if you have a camera with a high frame rate. Feel free to use that part of this video for said demonstration purposes.

Also the top of the slinky fell with a constant velocity (!) which is what you can see being tracked in the graph, though we never found out why. It even did this in our simulation, which was even weirder considering we didn’t know why.

First of all we thought that it might initially be accelerating faster than a point particle just falling under gravity as it also has the spring force acting down on it and then reach constant velocity when the spring below exerted a restoring force upwards that was equal to the strength of gravity pushing down and then we realised that duh—it’s a slinky. Slinkies aren’t like normal springs under compression—they are quite happy to sit back together. The constant velocity might be due to loss of energy with the inelastic collisions the coils make with each other as they collide, but hmm. If you have an idea, feel free to comment!

 Also my sister and I just made 3D Dinosaur cookies!!

Yey Dinos!

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