The Bucket Squirt Phys-elation

There are occasions when you can get hopped up on physics. You'll be taking it easy exploring a bit of physics when BAM! You find out about something revolutionary. Something like quantum tunnelling. It leaves you shocked and excited. Perhaps even sit-down excited. It's the physics feel good moment. A phys-elation. It's not the same as a eureka moment, but it is a good thing that happens more than once. Sometimes you'll know it's coming, sometimes you won't. But, they're pretty hard to forget.

Physics not drugs!

A Phys-elation Memory

Despite being hard to forget, I've never really reminisced about a phys-elation. Nonetheless, whilst writing The Seaside Physics Juxtaposition, a particular phys-elation memory crawled back to the surface of my mind. It was at A level, learning about circular motion. If you swing around a bucket of water fast enough, the constant change in velocity will force the water to stay in the bucket. However, if the bucket has a hole in bottom, water will squirt out of the hole... most of the time. If the holey bucket is being swung vertically, there is a point at the top  of the swing where the force of gravity can equal the centrifugal force that makes the water squirt out.

If you want to know the equation, the velocity for a squirt free climax has to be:

in which g is the acceleration due to gravity and r is the distance to the bucket from the pivot - your shoulder.

When the velocity is this value at the climax of the swing, water will stop squirting out. All standard stuff, no phys-elation at this point.

After learning this, we (the class) wanted proof, so we spent the rest of the lesson getting it. And we got it. This is our recording taken by a phone taped to a holey bucket of water being swung around.

It wasn't a eureka moment... but it was a phys-elation! You know what they say, small things please small minds, but not all minds pleased by small things are small minds... savvy?

The Circular Motion

If you want to look up any of the physics mentioned here, The Fitzpatrick Physics Files will direct you to a perfect resource for it. Specifically the Classical Mechanics notes.

That bit at the end...

The video above is courtesy of Skipper - it was his phone that recorded it. Skipper blogs over at Confessions of a Wildlife Biologist. You should check it out! Thanks to Skipper for risking his phone all those years ago!

Confessions of a Wildlife Biologist,

Read More »

The Vagabond Decision Algorithms

In the last blog post, I was in the scenically crowded seaside town of Whitby. Since that time I have packed my bindle and journeyed on southward. When it came to unpacking, I had to pause for awe. There was so much packed, it was ridiculous! But it reminded me of something. It reminded me of the bin packing algorithm. This bit of maths comes under the umbrella known as "Decision Mathematics". Of course, it's basically about making decisions using mathematical reasoning, such as with algorithms.

The Vagabond Decision Algorithm.

Decision Maths on the Cranium

Decision maths (DM) is something for the physicist, and something for the Cranium List. The reason for it making the list is that it's interesting, doesn't take long to pick up, and has links with quantum computing like with Shor's algorithm for quantum factorisation.

There are various resources that you could use to learn DM. However, I don't think that you need to spend 5 minutes watching a YouTube video about one algorithm when you could learn it in a single minute. Similarly, I don't think that you need to spend 5 minutes reading about an algorithm. So, here's the 3 resources:

The Student Room

Uncovered at Student Room D1 Revision Notes. It's well laid out, simply worded, has examples and has some video links. Unfortunately the algorithms are on different pages so you need to click through them.

The Student Room.

WikiBooks

Buried at WikiBooks OCR D1. This is a vague summary of the OCR course book for A level DM. (It's actually the book that I used.) The bonus of this resource is that the relevant notes are all one page.

WikiBooks

@ilovemathsgames

Also worth a mention is Decision 1 for Numpties. These are hand-written notes by a maths teacher (@ilovemathsgames). Although they have a good content, they remind me of when I would borrow girls notes at college!

Decision 1 for Numpties.

Final Words

Depending upon which part of physics interests you, you may never use anything from DM. But that doesn't mean you shouldn't know it, especially when it has quick rewards. Decision 1 is the first out of 2 modules in decision maths at A level. So you can dig a bit deeper if you like. As a final word, a good vagabond should know packing and route inspection algorithms, but unlike a regular vagabond, my bindle is actually a Peugeot 206...

That bit at the end...

It was very alarming when, 10 days after publishing this post, my blogger app decided to betray me. It completely removed the Vagabond Decision Algorithms post. As in, the entire post was lost. My day spiralled out of control. I was a lost cause. Hours later, submerged in empty bourbon cream packets and a tangled cardigan, I found some reluctant energy. Determined, I managed to discover a chrome extension that allowed me to load a cached webpage...  The Vagabond Decision Algorithms was back in the room!

Read More »