This week I are mostly been reading...

September 15th, 2007

A pretty book about mathematics and programming

An enlightening book about the mechanism of evolution

A beautifully written yet brutally filthy diary of a London call girl

And I can recommend them all!

When scientists get bored

June 24th, 2007

Its a lazy Friday afternoon. You've got a PHD in something unpronounceable and a lab full of funky Tesla coils. There's nothing to do but boring paperwork. How do you procrastinate?

Click here for video

The scientific method: Lost

June 8th, 2007

In a recent article I voiced my opinion that Charlie really didn't have to die in Lost. If you're too lazy to read that article, he basically got trapped in a submerged watertight room. The glass porthole of the room was blown out by a suicidal grenade-wielding Russian and the water rushed in. The room filled up rapidly and poor Charlie drowned.



I suggested that there was rather a lot of TV physics going on to artificially drown Charlie in a situation that shouldn't have been immediately fatal to him.

The scientific method can help us out here. Lets do science!

Observe
In the image the room is flooded to the roof with water. In other films I've seen characters survive in air pockets in capsized ships and so on.

Hypothesise
I hypothesise that where you have a mix of air and water in a sealed space, the air makes its way to the highest point. I also hypothesise that water and air cannot occupy the same space.

Predict
In a sealed vessel such as the one Charlie was trapped in, an air pocket would form once the water level inside the room was higher than the porthole. This should work for vessels of any size, with portholes in any position.

Experiment
Here's where it gets interesting (I know, finally). My experimental plan is to submerge an airtight vessel then remove the cap making a large porthole, just like Charlie's watery prison. Then when the water has stopped rushing about I'll re-cap the vessel and remove it from the water to see if there is any air trapped inside.



If my hypothesis is right I should see a fair amount of space within the vessel that is not filled with water. If it comes out full of water, the hypothesis is falsified and Charlie should have drowned after all.

Now, I don't have a life-sized vessel and a conveniently deep pool of water for this. I'm going to use an empty plastic drink bottle and a sink full of water.

Results

Apparatus: Bottle, sink, water.


Vessel fully submerged, with cap in place. The bottle is airtight at this point and is completely full of air.


Cap has been removed and water is flooding in. Note the air bubbles rising from the opening showing escaping air as the water enters. Yes, I do know my drain plug is going rusty.


Everything has settled now. No more water is entering and no more bubbles of air are escaping. The water line around my hand shows that the bottle is still fully submerged. Note the waterline appears to be around the middle of the bottle. Ie, the vessel is only half full, even with no cap on.


The cap is now replaced with the bottle still underwater to lock the amount of water/air in the bottle. Upon removal, it is clear that there is not only an air pocket in the bottle, but that it is about 40% of the volume of the vessel. The water has entered until the porthole was fully covered. At this point no more air can escape and therefore no more water can get in.


So Charlie could have survived. In fact, he could have survived easily, even if he couldn't swim. He could have stood with his feet on the floor and still had his head above water. Could this be an example of when TV physics goes bad?

Thought exercise: Under what conditions might the room have flooded completely?

The scientific method made easy

June 6th, 2007

There's a fair bit of confusion about what scientists do that makes what they claim so right. Turns out it is something called The Scientific Method. That's a grand name for a way of getting ever closer to the truth of how things really work.

Briefly:
1. Observe
2. Hypothesise
3. Predict
4. Experiment

I'm going to expand on that in a moment, but we need to understand a few important words first:

  • A scientist is just a normal person, doing science. You don't need a huge brain or a degree or a lab or even a white coat. You just need to follow the scientific method carefully.
  • A hypothesis is a tentative description of how something works. This can be a plain English explanation or a mathematical formula or whatever is suitable.
  • A theorem or theory is a hypothesis that has stood the test of time and become generally accepted as right.


Now we can look at those steps again. Here we go:
1. Observe something interesting, and collect data about it.
2. Come up with an explanation of it. This is your hypothesis.
3. Predict new things that should happen if you are right.
4. Perform experiments to find out if you were indeed right.

That last step includes peer review. Other scientists look at your work and perform your experiments again. For any hypothesis to stand a chance of being confirmed, it needs to be verifiable by anyone bored enough to try it for themselves.

You may have spotted that no theory is ever invincible. Any theorem known to science could be disproved at any time, and it potentially only takes one piece of evidence to do so. Suppose a brave yet crazy balloonist made it to the moon in his dirigible. We'd have to rethink the theory that the atmosphere doesn't go up that high.

This is really where the power of the scientific method comes from. This is what gives scientists the ability to realise they were blithering idiots to have thought things were like that, when such things are clearly like this.

Theories might sound a bit uncertain then. The thing is, to be called a theory there must be an extreme body of supporting evidence. So much so that theories are often called scientific laws. You've probably heard of things like The Law of Gravity, and Newton's Laws of Motion. These are theories and can still potentially be disproved. In fact, Newton's Laws don't really work for really really fast things and really really small things. Shows how smart he was.

It is worth noting that any valid hypothesis must stand with all other theories without contradiction. Imagine I hypothesise the moon is made of cheese. Suppose you suggest the moon is made of wood. We can't both be right as our hypotheses contradict each other. Furthermore, one hypothesis being wrong does not mean the other is automatically right! We could easily both could be wrong.

For any hypothesis to be considered scientific it must be falsifiable. Suppose I hypothesise that all washing machines contain gremlins that eat socks and vanish when the machine is inspected. The claim cannot be shown to be false because any experiment looking for the gremlins would make them vanish. Curiously, the related hypothesis - there are no sock-eating gremlins in washing machines - is scientific. You could in theory falsify the claim by catching a sock-eating gremlin inside a washing machine.

Finally, it should be pretty clear that simply having a hypotheses nearby does nothing to demonstrate its validity. For example none of the above suggests that there really are sock-eating gremlins!

Powers of ten

May 27th, 2007

If you've never seen this classic short film before, set 10 minutes aside and watch closely. The premise is simple - start at a metre and zoom out by a factor of 10 every 10 seconds. How long before you can see the entire world? How long before the entire galaxy? How much further does human understanding of the universe go?

What about the other way? How many times can you zoom in by a factor of 10?



Click here to watch the video


If you're feeling a bit insignificant after all that, let The Simpsons parody of the same video make you smile again.

Physics and Intuition Answer

May 15th, 2007

In this article I posed a physics/intuition question for your ponderance. The point was to see how well you intuition served you in a simple bike puzzle.



If you stand to the side of the pictured pushbike and push the pedal backwards, which way does the bike go? Intuition tells us that the pedals will go round in the normal forward direction and hence the bike will run forward. Except that the only external force on the bike is pushing it backwards, so how can it go forwards? Ok, so if it goes backwards, how come the back wheel should be going forwards? It's all very confusing!

The short answer: It depends on the gearing.

The longer answer: If the gearing is tall (like most real pushbikes under normal use) then the bike will move backwards, and surprisingly fast. If the gearing is short (like the lowest hill climbing gears on a mountain bike), the bike will move forwards, slowly. If the gearing is just right, the backwards force from the push and the forwards force from the tyre will balance and the bike will stay still - up to the point where the backwards force overwhelms the tyre's grip where the bike slides backwards with the wheel stationary.

The proof: Download the video
In the video my 'bike' has four wheels so it doesn't easily fall over. The front of the bike is on the right of the screen. I'm pushing the pedals backwards with a stick as it's hard to get fingers into the small space where the model pedals are.

ID II

May 9th, 2007

Further to this post, I'm now back from the ID lecture. Thankfully it wasn't quite what I expected. I'm always happy to be surprised.

The speaker didn't go down the well trodden (and well refuted) paths of ID which was a good thing. Instead his argument revolved around the fact that when you look closely at technical reports made by biologists, they creep the word 'design' into their evolution papers. This seemed to be evidence enough to him that the universe was built by some sort of supreme intelligence.

This argument doesn't strike me as hard to argue against. Biologists will no doubt use words like 'design' whilst talking about evolution as a metaphor for the evolutionary process they really mean. They might say something like 'the eye has been designed by evolution' when they are really talking about the process of random mutations affecting the suitability of a unit's survival over a long time period. They don't write the full thing every time because the biologists who are intended to read it already get this concept, and are comfortable with shortening it to the useful metaphor of design. That doesn't mean they actually think there's real intelligent design going on behind the scenes.

The speaker's second argument was a little more thought provoking. He said you can create an experimental setting either in a computer or in a lab where the process of evolution can be shown to work. He went on to say however that the experiment would clearly have a designer, and that the evolution you've created was clearly designed - intelligently. He then extrapolates this to suggest that the universe and the evolution within it therefore are designed.

Now, it sounds like he's missed the point of the experiment there. It sounds like he hasn't worked out that the lab experiments are simply modelling the initial settings for real-life evolution, and that the real situation could have arisen naturally. He hasn't missed the point however; He's saying that whilst evolution works when the conditions are right, why should the natural conditions of the universe/Earth be right without them having been designed.

Now, you can start debating for naturalism here with the Anthropic Principle and various other cunning devices. It doesn't help much because we're really talking about how the universe was set in motion - a thoroughly unsolved problem to date.

This however was the unexpected part. I was expecting the whole Young-Earth Creationism 6000 years thing borne of Christian Fundamentalism. Instead he came with the most reasonable sort of deism - that something intelligent set off the universe and evolution has run its course largely unaided since.

ID

May 5th, 2007

On Wednesday I'm off to a lecture arguing for Intelligent Design. No, not arguing for the human use of intelligence whilst they're engaged in the act of designing things (which I'm all for), but the creationist kind. The lecturer will be actively arguing that life, the universe and everything is intelligently designed by a supreme intelligence.

I'm convinced he's wrong.

However, as a man of science I must be open to new evidence on a subject, even one that I'm pretty certain has been decided already. I'm not expecting to hear anything spectacularly thought-changing in this lecture, but I will go along, listen and consider anything that is said as potential evidence anyway. I've been to lectures from the other side (natural selection/evolution), and it's fair to allow some ballance and hear both sides.

This is where the scientific viewpoint is at it's most powerful. It is the starting point of doubt instead of the starting point of certainty. It is the ability to examine new evidence and decide if it supports or refutes existing knowledge, and to modify that knowledge as a result.

Physics and Intuition Question of the Week

May 5th, 2007

Try this as a thought experiment. There's no tricks here, just use your judgement to guess what should happen in the following physical setup. You have a bicycle with stabilisers stood on flat ground. It is a typical bicycle with nothing special about it other than the stabilisers that stop it falling over.



If you are stood to the side of the bike and set the pedals vertically, then you push backwards on the lower pedal what happens to the bike? The only external forces on it (gravity and your push) push the bike downwards into the ground, and backwards, which should mean it rolls backwards. But the pedals are being rotated forwards, which should mean the bike moves itself forward, right?

Take a guess with your intuition first, then try applying some logical reasoning to it. I'll post up the definitive answer with strong supporting evidence in a week or so.

Try to avoid googling for an answer before coming up with your own ideas first.

Profits or Principals

April 19th, 2007

A minor moral dilemma cropped up at work today when I spotted an opportunity for work for the company I'm employed at. We build viral games and advertising media, and that exact requirement was asked for in the exact area we operate. No dilemma there - the appropriate course of action is to pass the opportunity on to my boss and let him send it to the sales team as appropriate.

Except that the potential client in question is a zoo run by young-Earth creationists, with an agenda of spreading their nonsense to school-age children, persuading them to their point of view with fluffy animals. Worse still, they seem to mix real science fact with their own pseudoscientific fictions and clumsy logically-flawed misconclusions.

Now, theism is one thing. Religion another. Both can be debated sensibly, at least to a point. Young-Earth Creationism is a separate subject that attempts to reject the theory of evolution and replace it with a literal interpretation of the accounts in the Bible, coupled with any shred of scientific evidence that vaguely supports the case. This view ignores the mountains of evidence to the contrary, and is generally accepted to be false with as much confidence as can ever be given by science. Ie, as much as we are convinced that, say, the theory of gravity implies forces exist between massy objects, we are equivalently convinced that young-Earth creationism is wrong.

So teaching it to kids using cute animals as persuasion is wrong.

And so is building advertising material for it.

So with the real chance of the company winning the work, and the also real chance that it would actually be me who would build any game they'd want, should I have passed the opportunity on to my boss, or should I have kept it quiet?