What a Wonderful World Read Online Free PDF Page B

technology. It could transform the world.

    Notes
    1 This is the fundamental recipe for a steam engine, the driving force behind all activity (see Chapter 14, ‘We are all steam engines: Thermo dynamics’). Energy goes from a high-temperature environment – and electrons in an atom with a lot of energy have a lot of energy of motion so can be considered
hot
– to a low-temperature environment – and electrons with little energy can be considered
cold
. In the process, the energy does
work
. In other words, it drives something against a force – in the case of a steam engine, a piston against air pressure.
    2 The energy liberated by combining liquid hydrogen and liquid oxygen fuel is not quite enough to boost into space their combined weight
plus
that of the metal skin of a rocket. This is why a rocket is built in stages. A rocket, by dropping off a stage when it has climbed high into the air, makes itself lighter. Consequently, the fuel has an easier job of boosting it into space.
    3 The electrons in an atom are arranged in shells, each with a maximum complement of electrons. Having a complete shell is hugely desirable. Hydrogen can achieve this by losing an electron (in fact, its sole electron); oxygen by gaining two electrons. This is why an oxygen atom grabs electrons from two hydrogen atoms. The state in which two hydrogen atoms lose an electron and an oxygen atom gains two electrons is the lowest-energy, desirable state, the equivalent of a ball lying at the foot of the hill.
    4 Chemists talk of ‘oxidation’ and ‘reduction’ because, once upon a time, they did not know the precise details of what was going on in chemical reactions. In fact, an oxidising agent such as oxygen
grabs
electrons in order to reduce its energy, whereas a reducing agent such as hydrogen
donates
electrons to reduce its energy.
    5 Proteins are large biomolecules used for a variety of purposes such as providing the scaffolding of cells and speeding up chemical reactions.
    6 A proton, which is roughly 2,000 times more massive than an electron, is one of the two constituents of the core, or nucleus, of an atom. The other is a neutron. All atomic nuclei contain both particles , apart from the nucleus of a hydrogen atom, which contains only a proton.
    7 Naively, it might be thought that an electron simply slams into a proton, driving it through a pore in the cell membrane. Actually, the electron changes the shape of a protein; it has one shape without the electron and another with the electron. Such shape changes force a proton across the membrane.
    8 See Chapter 8, ‘Thank goodness opposites attract: Electricity’.
    9 Although the average person can survive without food for at most a month, there have been cases where people who are very obese have lived for a year on nothing but their own stored fat.
    10 ‘The volume of blood passing through the human heart in an average lifetime would be enough to fill three supertankers,’ according to @Qikipedia on Twitter.
    11 Solar energy is not the only energy source of life on Earth. Some organisms exploit geochemical energy – for instance, the chemical reaction between molecular hydrogen (H 2 ) and carbon dioxide (CO 2 ). This is believed to have powered the very first living things on our planet.

3:
WALKING BACKWARDS TO THE FUTURE
    Evolution
    Evolution is a tinkerer.
    FRANÇOIS JACOB , ‘Evolution and Tinkering’
    Pigs look us straight in the eye and see an equal.
    WINSTON CHURCHILL

    Question: What do aeroplanes and television sets and lamp posts have in common with frogs and whales and people? Answer: All are highly improbable configurations of matter and all do what they do extremely well. The technological things in the first group were designed by human beings. An obvious conclusion to draw from the similarity between the two groups would therefore be that the living things in the second group were also designed. The obvious conclusion, however, is wrong.
    The illusion of design in