Discovery of X-rays, electrons and the first liquid-fuelled rocket

  1. Discovery of X-rays:
  • German physicist Wilhelm Rontgen discovered X-rays in 1895 while he was investigating cathode rays (electrical discharges inside a tube containing very little air).
  • He noticed that when the tube was working, some crystals lying nearby glowed, even though the tube was shielded so that no light could escape from it.
  • He worked out that the cathode rays, hitting the glass of the tube, were producing other rays that made the crystals glow.
  • He did some further experiments, which showed that the rays could pass through solid objects and affect photographic plates.
  • This led him to make the first ever X-ray picture.
  • Rontgen was at first not sure that he should announce his discovery and was worried that other scientists might not believe him.
  • But soon everyone was talking about the new rays that made hidden things visible.
                                        Wilhelm Rontgen and the X-ray image
  1. Discovery of electron:
  • British physicist J. J. Thomson was the first person to show that atoms contain smaller particles.
  • He studied cathode rays and, by subjecting the rays to electric and magnetic fields, he showed in 1897 that they consisted of negatively charged particles.
  • Thomson discovered that it made no difference what materials he used, and he concluded that the particles existed in everything.
  • He believed that they were lighter and could move faster than any atom, and realized that he had found something new.
  • We now call the particles electrons.
                                                                                             Discovery of electron
  1. The first liquid-fuelled rocket:
  • The first rocket used solid fuels.
  • They were really just big fireworks.
  • Modern rockets use liquid fuel, which allows much more controllable motors to be built.
  • The first liquid-fuelled rocket was launched by US physicist Robert Goddand.
  • Burning petrol and liquid oxygen, it lifted off briefly from his Aunt Effie’s farm in Auburn, Massachusetts, on 16 March, 1926.
  • It was another 15 years before the same idea was used in Adolf Hitler’s deadly flying bombs during the Second World War.
                                                                            Robert Goddand and the first liquid-fuelled rocket