We are all made up of atoms. In fact, we consist of nothing else. The human body contains approximately 4,000 quadrillion atoms. These atoms belong to various elements such as oxygen, carbon, hydrogen, nitrogen, phosphorus and potassium. Atoms are extremely small, being only about 0.0000000001 m in diameter.

The majority of an atom's mass is concentrated in its dense nucleus. The size of an atom's nucleus is around 0.000 000 000 000 01 m, and its volume is only one hundred billionth of the atom's total volume. The nucleus is surrounded by an almost completely empty space. In this space, you can find electrons that determine how the substance behaves chemically. This electron cloud consists of only a few electrons that are so small that their size cannot be measured. If an atom's nucleus is represented by pin head the size of 1 mm, then the whole atom would be represented by a sphere approximately 10 metres in diameter. 

The whole living world is built around carbon atoms. Every cell in every human, animal and plant contains carbon atoms. We eat carbon atoms during every meal and inhale them into our lungs with every breath we take. But how does a carbon atom know that it must be carbon and not gold, for example? The tiny small nucleus at the centre of an atom is made up of two types of nuclear particles: protons and neutrons. The number of protons in the atom's nucleus determines its element. Hydrogen has one proton, helium has two, carbon has six, uranium has 92, gold has 79, etc. So the question arises, could we make gold from some cheaper substances? Perhaps by combining tin (50 protons) and copper (29 protons)? Mixing tin and copper in a vessel does not produce gold, as both atoms remain unchanged. If, on the other hand, we succeed in bombarding the tin with copper so strongly that the copper nuclei penetrate the tin nuclei, we could theoretically obtain gold.