## Posts Tagged ‘Theory’

### Idiot

January 20, 2008

It’s funny how some words come about. Idiot is a good example. The word idiot is derived from the Greek word idiōtēs meaning “person lacking professional skill”, the Latin word idiota meaning “ordinary person” and the Old French word idiote meaning “uneducated or ignorant person”.

Scientifically speaking the word ‘idiot’ refers to someone who has an intelligence quotient, or IQ, of less than 20. To put that in perspective:

• 50% of people have an IQ less than 100.
• 15.9% of people have an IQ less than 84.
• 2.3% of people have an IQ less than 68.
• 0.1% of people have an IQ less than 52.
• 0.003% of people have an IQ less than 36.
• 0.000028% of people have an IQ less than 20.

So about 1 in every 3,500,000 people is an idiot, psychologically speaking. For comparison quite a lot of people are geniuses, that is, about 0.5%, or 1 in 200, people have an IQ score over 140 (this graph makes it easy to understand).

By the way the above figures are based on IQ test scores with a standard deviation of 16 points.

### The fastest thing in the universe

January 12, 2008

No it’s not a Cheetah which can run at 115 kilometres per hour, or a Peregrine Falcon which can dive at 300 km/h. It is light.

The speed of light is exactly 299,792,458 metres per second, or 1,079,252,848.8 km/h.

This diagram shows how long it takes light to travel from the earth to the moon, 1.2 seconds.

Pretty quick hey.

### Einstein’s famous equation

January 12, 2008

Albert Einstein was a really, really smart guy. He was an amazing thinker and he is probably most well known for this really famous equation:

E = mc²

But what does “the energy of a body (E) equals its mass (m) times the speed of light (c) squared”, or E = mc² actually mean?

Well basically it shows that mass can be converted into energy and vice-versa. To appreciate the significance, consider this example:

E is energy in joules, m is mass in kilograms and c is the speed of light in metres per second. Using the equation the energy released by only 1 kilogram of matter

= 1 x 300,000,000 x 300,000,000 joules

= 90,000 million million joules

= energy released by 20,000 kilotons of TNT.

Now the Hiroshima atomic bomb was only a 15-kiloton bomb so 20,000 kilotons is A LOT OF ENERGY to come from only 1 kilogram of matter!

The formula E = mc² made the creation of nuclear weapons possible, something the pacifist Einstein was not particular pleased about.

### The Red Pill

December 19, 2007

The scientific method is great! It involves the collection of data through observation and experimentation, and the formulation and testing of hypotheses (or guesses). For example, if I want to discover if a tennis ball bounces higher than a basketball I can design a scientific experiment to find out the answer.

Unfortunately it doesn’t always work. Some questions have no answer. One of my favourite philosophical questions is the ‘Brain in a vat‘. In short, how do you know that you are sitting there at a computer on Earth reading this post? How do you know that your brain is not somewhere completely different being fed a series of electrical stimulations by a supercomputer which is fooling you into thinking your on Earth?

The movie ‘The Matrix’ (imdb, wikipedia) supposes a similar thing. This clip shows Neo going from ‘the matrix’ back to the ‘real world’:

So my question is – how do you know you are where you think you are? And if you think you know – PROVE IT!

### Why is grass green?

November 6, 2007

Very interesting question. Grass is green because it has a green pigment in it called chlorophyll. Chlorophyll is located inside organelles (little factories) called chloroplasts which themselves are located inside the leaf cells. Chlorophyll absorbs sunlight which enables the chloroplasts to conduct a process called photosynthesis. Photosynthesis is a really important reaction. It converts carbon dioxide and water into glucose and oxygen. In simplified form it is written as:

Carbon Dioxide + Water → Glucose + Oxygen

Imagine if leaves weren’t green and they didn’t produce food (glucose) and oxygen. That would be bad!

### Absolutely FREEZING

October 23, 2007

Things can get pretty hot sometimes. The hottest temperature ever measured on Earth was 53.9 °C in Death Valley, California. The temperature at the surface of the Sun is about 5500 °C, and the temperature at the core of the Sun is over 15 million °C. But that’s not all. In 2006 a machine called a Z machine produced plasmas that exceed temperatures of 2 billion °C (read more here).

Conversely the lowest temperature ever recorded was -89.2 °C on 21 July 1983 in Vostok, a Russian Antarctic research station. This is nearly as cold as it gets, because the lowest limit of temperature, known as Absolute Zero, is a mere -273.15 °C. That’s right nothing can ever get colder than -273.15 °C !

Although I have used the Celsius (°C) temperature scale in this post most scientists actually use the Kelvin (K) scale when referring to temperature. When using the Kelvin scale, absolute zero is 0K.

To do conversions between Celsius and Kelvin use these formulae:

°C = K − 273.15

K = °C + 273.15

### Internet ≠ World Wide Web

October 21, 2007

Internet = World Wide Web is an extremely common mistake, they are NOT the same thing.

The World Wide Web (WWW) is a widely used information system on the Internet that provides facilities for documents to be connected to other documents by hypertext links. People browse the WWW using web browsers like Explorer and Safari.

The Internet is an international computer network that provides the backbone for the WWW, e-mail and other things like chat (MSN, iChat) or file sharing.

When one considers the popularity of the WWW today it is amazing to think that it only became popular in the mid 1990′s. In fact the first web site ever built was only put online in 1991. The WWW was actually created by a guy named Tim Berners-Lee. He created computer technologies like HTML and HTTP, you have probably seen ‘http’ written at the start of nearly every web address you’ve ever seen!

Amazing how fast technology moves these days!

If you’re interested in the history of the Internet or the WWW read more here, here or here.

### Getting old at the tip

October 6, 2007

Living things are made up of cells and cells are controlled by a molecule called DNA. In cells DNA forms structures called chromosomes. Humans have 23 pairs (total of 46) of chromosomes – you get 23 from your Mum and 23 from your Dad. Chromosomes look like this:

They have a centromere in the middle and telomeres on the end. The interesting thing about telomeres is that scientists believe they play an important role in ageing. Apparently as you get older your chromosomes get shorter and shorter because every time your cells replicate they lose a little bit of telomere at the ends.

When they get too short, the cell can no longer divide and it dies. And I suppose when all the telomeres in all of your cells get to short you’re in trouble!

New research shows that telomeres do more than just control ageing too.

### Johann Doppler

September 27, 2007

Johann Christian Andreas Doppler is famous for discovering what became known as the doppler effect. You hear it all the time when an ambulance with it’s siren going drives past. This diagram illustrates it well:

In part ‘a’ when a train blowing it’s whistle is standing still, a person behind it and a person in front of it will hear the same sound. But, if the train is moving forward (diagram ‘b’) it compresses the sound waves it emits in front of it and stretches them out behind it. As a result the person in front hears a higher pitched noise than the person behind.

Interestingly the same thing happens with light (diagram ‘c’). When a light emitting source, say a star, is moving away from us the light waves are slightly lengthened and as a result the light looks more red (check out this post for more information on light wavelengths). This phenomena is called red shifting and happens to the light from all stars. This is because all stars are moving away from us because the universe is expanding.

Wow that was a bit full on wasn’t it!