# Transition Year

I don't quite know where this comes from but I accredit it to Mr. Murray.

It would make a good finishing test for a module of constructivist science!

Mr Cunningham 19/05/2007

Form 4 Physics Test

I have put together what I consider to be some of the most important ideas in Science and will expect you to have read them and be able to comment on any five ideas.

You will only have 20 minutes for this section, which means four minutes on each topic here. You can try to learn them, or if you wish you can choose to disagree with one or more of the ideas. But as with all arguments you must try to support your position.

Science does not offer absolute proof

Scientists can never be 100% sure about anything. There is a common misconception among non-scientists that science can prove things absolutely. A scientist, when asked by a reporter: “can you reassure the public that this genetically modified food / mobile phone mast / medical procedure is absolutely safe?” must answer “no”, even if he (or she) wants very much to say “yes”.

It then becomes very easy for a news-editor to use this to generate scare-mongering headlines like: “Scientists admit phone-mast may cause cancer!”

Our science education system is largely to blame here; we give the impression that our experiments can prove something without doubt. Take the demonstration to show that solids expand when heated. We fit a metal sphere through a ring when cold and then heat the sphere and show that it doesn’t fit through the ring when hot. We then generalise by saying that this proves that all metals expand when heated (presumably over all temperature ranges). Why might it be wrong to do this? Why might it be okay to do this? Can you apply this reasoning to any other science demonstration?

Kinetic Theory

Everything is made up of atoms and all atoms vibrate. The hotter the temperature the greater the speed of vibration. The amplitude of the motion is also greater and therefore the object expands.

This may seem like a pretty boring idea, but it is the first step in understanding the atomic world. It allows us to explain macroscopic properties such as pressure, temperature and volume. Indeed the atom was generally thought of as being a hypothetical construct rather than a real object up until as recently as 100 years ago.

The atom is mostly empty space

Each atom is 99.999999999 % empty. Now all matter, including you, me and whatever you happen to be sitting on, is made up of atoms. Which means you are almost completely empty space! In fact if we could somehow remove all this empty space in your space in your body and just keep the solid bit, it would be about the size of a grain of sand! So why do objects look and feel solid?

This was famously summed up by one scientist who claimed that “the world is not only queerer than we suppose, it is queerer than we can suppose”.

We are Stardust

Hold up your hand. You are looking at stardust made flesh. The iron in your blood, the calcium in your bones, the oxygen that fills your lungs every time you take a breath – all were baked in the fiery ovens deep within stars and blown into space when those stars grew old and perished.

Every one of us was, quite literally, made in heaven.

Evolution

Humans and apes have all evolved from an apelike ancestor that lived on earth a few million years ago.

And while there is still disagreement between scientists over the rules which govern evolution, there is no dispute about the fact of evolution itself.

How old are you?

The universe is approximately 14 billion years old. Planet Earth is about 4.5 billion years old. The first living cell arose four billion years ago and from that all life today has developed..

First modern man appeared less than 200,000 years ago. Neanderthal man died out about 25,000 years ago.

Stretch out your arm. If the distance from the middle of your throat to the tip of your middle finger represents the length of time since life began up untill now, then the whole of recorded human civilisation is in the few grains of dust that falls with the stroke of a nail-file on one finger.

Extinction of species

Most biologists view the present era as part of a mass extinction event, possibly one of the fastest ever; it is known as the Holocene extinction event.

Extinction is the disappearance of an entire species. Surprisingly it is not an unusual event, as species regularly appear through speciation, and disappear through extinction.

Over 99% of species that ever lived are now extinct.

In the past, life on Earth has experienced five mass extinctions. The most devastating, perhaps, was the Permian mass extinction 225 million years ago. About 90% of the species living at the time went extinct, including most of the dominant land vertebrates at the time.

The K-T extinction, 65 million years ago, is famous for killing off the dinosaurs, along with two-thirds of all species on Earth. However, small mammals, turtles, crocodiles, birds, redwood trees and many others survived. There is very good evidence that a giant asteroid crashed into the planet at this time and may have been the main cause of the extinction.

The animal population on the planet Earth has dropped by over a quarter since 1970

The WWF (World Wildlife Fund) released a report which stated that their Living Planet Index (LPI), which tracks nearly 4,000 populations of wildlife, shows an overall fall in population trends of 27% between 1970 and 2005.

Global Warming and Climate Change

The 1990s have been the warmest decade since records began in 1861.

The average global air temperature near the Earth's surface increased 0.7 °C during the hundred years ending in 2005.

Climate model projections indicate that temperature could rise by up to 6 °C during the twenty-first century.

The impacts of climate change will fall disproportionately upon developing countries and the poor persons within all countries, and thereby exacerbate current inequities.