Inventions, Discoveries & Scientists

• A discovery means finding something that already existed in nature but was unknown before.
• An invention means creating something brand-new that nature never made, built by human effort.
• You discover facts of nature – bacteria, the cell, gravity, oxygen, X-rays.
• You invent machines or tools – telephone, bulb, aeroplane, steam engine.
• Memory trick: if the answer is a natural fact it is a discovery; if it is a man-made device it is an invention.
• The exam loves to test this difference, so fix it firmly first.

A discovery means finding something that already existed in nature but was unknown before.

An invention means creating something brand-new that nature never made, built by human effort.

You discover facts of nature – bacteria, the cell, gravity, oxygen, X-rays.

You invent machines or tools – telephone, bulb, aeroplane, steam engine.

Memory trick: if the answer is a natural fact it is a discovery; if it is a man-made device it is an invention.

• Darwin's idea is natural selection – "survival of the fittest"; best-suited organisms survive and pass on traits.
• Easy split: Leeuwenhoek = bacteria, Hooke = cell.
• Gregor Mendel, "Father of Genetics", found the laws of inheritance using pea plants.
• Charles Darwin wrote On the Origin of Species (1859) and gave the theory of evolution.
• Common trap: Origin of Species is Darwin, NOT Lamarck, Linnaeus or Mendel.
• Antonie van Leeuwenhoek, "Father of Microbiology", built a simple microscope and first saw bacteria ("animalcules").
• Robert Hooke discovered the cell by seeing box-like rooms in thin cork.

Darwin's idea is natural selection – "survival of the fittest"; best-suited organisms survive and pass on traits.

Gregor Mendel, "Father of Genetics", found the laws of inheritance using pea plants.

Charles Darwin wrote On the Origin of Species (1859) and gave the theory of evolution.

Common trap: Origin of Species is Darwin, NOT Lamarck, Linnaeus or Mendel.

Antonie van Leeuwenhoek, "Father of Microbiology", built a simple microscope and first saw bacteria ("animalcules").

Robert Hooke discovered the cell by seeing box-like rooms in thin cork.

• Word "vaccine" comes from vacca (Latin for cow), after Jenner's cowpox method.
• Arthur Kornberg first made DNA in a test tube (in vitro, 1956) by discovering DNA polymerase; Nobel 1959.
• In vitro means in glass / test tube; in vivo means inside a living body.
• Christiaan Barnard did the world's first human heart transplant (3 Dec 1967) at Cape Town, South Africa.
• Edward Jenner performed the first ever vaccination (1796) against smallpox using cowpox; "Father of Immunology".
• Traps for the Jenner question: Koch, Lister and Metchnikoff are common wrong options.

Word "vaccine" comes from vacca (Latin for cow), after Jenner's cowpox method.

Arthur Kornberg first made DNA in a test tube (in vitro, 1956) by discovering DNA polymerase; Nobel 1959.

In vitro means in glass / test tube; in vivo means inside a living body.

Christiaan Barnard did the world's first human heart transplant (3 Dec 1967) at Cape Town, South Africa.

Edward Jenner performed the first ever vaccination (1796) against smallpox using cowpox; "Father of Immunology".

• Memorise each name beside its single defining contribution; the exam swaps them as distractors.
• Edward Jenner — First vaccine (smallpox); Father of Immunology
• Alexander Fleming — Discovered penicillin (first antibiotic)
• Louis Pasteur — Germ theory of disease; pasteurisation
• Robert Koch — Proved specific germs cause TB and cholera
• Joseph Lister — Father of Antiseptic Surgery
• Elie Metchnikoff — Discovered phagocytes (germ-eating cells)
• Casimir Funk — Coined "vitamine"; discovered vitamins

• DNA is shaped like a twisted ladder (double helix) of two strands.
• Watson, Crick and Wilkins shared the Nobel Prize (1962) for this work.
• Arthur Kornberg made DNA in a test tube – do not confuse with discovering its structure.
• James Watson and Francis Crick discovered the DNA double helix structure (1953).
• They built on the X-ray images taken by Rosalind Franklin and Maurice Wilkins.

Watson, Crick and Wilkins shared the Nobel Prize (1962) for this work.

Arthur Kornberg made DNA in a test tube – do not confuse with discovering its structure.

James Watson and Francis Crick discovered the DNA double helix structure (1953).

They built on the X-ray images taken by Rosalind Franklin and Maurice Wilkins.

• The Wright Brothers (Orville & Wilbur) built and flew the first powered aeroplane (1903) at Kitty Hawk, USA.
• Traps for the aeroplane: James Watt only improved the steam engine; Davy made the safety lamp; von Braun built rockets.
• A single inventor is usually the answer for everyday machines.
• Aeroplane — Wright Brothers (1903)
• Electric bulb — Thomas Edison
• Telephone — Alexander Graham Bell
• Radio / wireless — Guglielmo Marconi
• Television — J. L. Baird
• Miners' safety lamp — Humphry Davy
• Wilhelm Rontgen discovered X-rays – a discovery, not an invention.

The Wright Brothers (Orville & Wilbur) built and flew the first powered aeroplane (1903) at Kitty Hawk, USA.

Traps for the aeroplane: James Watt only improved the steam engine; Davy made the safety lamp; von Braun built rockets.

• Key idea: tell apart safe sound waves from harmful radiation.
• Ultrasonic waves (ultrasound) are sound above 20,000 Hz, beyond human hearing, and are safe.
• Ultrasound watches a growing fetus in the womb and scans soft organs like liver and kidney.
• X-rays are high-energy radiation, not sound; they pass through flesh but are blocked by bone.
• X-rays clearly show bones, teeth and fractures.
• X-rays can harm a developing baby, so they are avoided in pregnancy – hence ultrasound is used instead.
• Ultrasound — Safe sound (>20,000 Hz) — Scanning fetus, soft organs
• X-rays — Harmful radiation — Imaging bones, fractures, teeth

Key idea: tell apart safe sound waves from harmful radiation.

Ultrasonic waves (ultrasound) are sound above 20,000 Hz, beyond human hearing, and are safe.

Ultrasound watches a growing fetus in the womb and scans soft organs like liver and kidney.

X-rays are high-energy radiation, not sound; they pass through flesh but are blocked by bone.

X-rays can harm a developing baby, so they are avoided in pregnancy – hence ultrasound is used instead.

• A vaccine is a harmless dose – a dead, weakened or partial germ – given so the body learns to fight the real disease later.
• The body responds by making antibodies and memory cells against that germ.
• When the real germ attacks later, the body fights it off quickly; this is immunity.
• Vaccines protect against diseases like smallpox, polio, measles and COVID-19.
• Smallpox is the first disease ever eradicated by vaccination.

A vaccine is a harmless dose – a dead, weakened or partial germ – given so the body learns to fight the real disease later.

The body responds by making antibodies and memory cells against that germ.

When the real germ attacks later, the body fights it off quickly; this is immunity.

Smallpox is the first disease ever eradicated by vaccination.

• COVID-19 is caused by the SARS-CoV-2 coronavirus; the disease began spreading in 2019-2020.
• Covaxin is India's first indigenous vaccine, made by Bharat Biotech with ICMR (inactivated virus type).
• Covishield is the Oxford-AstraZeneca vaccine made in India by the Serum Institute of India (SII).
• Pfizer-BioNTech and Moderna are mRNA vaccines used worldwide.
• Sputnik V is the Russian COVID vaccine; India's first dose was given on 16 January 2021.
• Covaxin — Bharat Biotech + ICMR — Inactivated virus
• Covishield — Serum Institute (Oxford-AZ) — Viral vector
• Pfizer / Moderna — Pfizer-BioNTech / Moderna — mRNA
• Sputnik V — Gamaleya, Russia — Viral vector

COVID-19 is caused by the SARS-CoV-2 coronavirus; the disease began spreading in 2019-2020.

Covaxin is India's first indigenous vaccine, made by Bharat Biotech with ICMR (inactivated virus type).

Covishield is the Oxford-AstraZeneca vaccine made in India by the Serum Institute of India (SII).

Pfizer-BioNTech and Moderna are mRNA vaccines used worldwide.

• Casimir Funk coined the term "vitamine" (1912) and is credited with discovering vitamins.
• Karl Landsteiner discovered the ABO blood groups.
• Hargobind Khorana, an Indian-American, helped decode the genetic code (Nobel 1968).
• Alexander Fleming discovered penicillin (1928), the first antibiotic, from a mould.
• Ronald Ross discovered that mosquitoes spread malaria; Nobel Prize 1902.

Casimir Funk coined the term "vitamine" (1912) and is credited with discovering vitamins.

Karl Landsteiner discovered the ABO blood groups.

Hargobind Khorana, an Indian-American, helped decode the genetic code (Nobel 1968).

Alexander Fleming discovered penicillin (1928), the first antibiotic, from a mould.

Ronald Ross discovered that mosquitoes spread malaria; Nobel Prize 1902.