Italy Secondaria di secondo grado – classe 5ª (esame di Stato) Natural sciences (scienze applicate)
Chapters: 3
1. Chemistry
Organic chemistry and materials science
- Materials Science: Why Materials Behave the Way They Do – Materials science links what a material is made of inside (atoms, bonds, crystals, grains) to how it behaves (strong, bendy, brittle, light). The four families are metals, polymers, ceramics and composites. We measure properties with tests: tensile test (stress = force ÷ area, strain = extension ÷ length, Young's modulus = stress ÷ strain), hardness tests and impact tests. Heat treatment and alloying change the inside and so the properties. New materials include composites, nanomaterials, smart materials and biomaterials. Chemistry also explains art materials: pigments, binders, ceramics, glass and metals.
2. Biology
Biochemistry and genetic engineering
- Biotechnology: Principles and Processes (Recombinant DNA Technology) – Genetic engineering means changing the genes of a living thing on purpose. We cut the gene we want with restriction enzymes (molecular scissors), paste it into a carrier DNA called a vector using DNA ligase (molecular glue), put it into a host cell, pick out the cells that took it, and grow them in big tanks (bioreactors) to collect the product. PCR makes millions of copies of a gene, and gel electrophoresis sorts DNA pieces by size.
3. Earth science
Weather and tectonics
- Distribution of Oceans and Continents: Drift, Spreading and Plates – In 1912 Alfred Wegener said all continents were once one landmass, Pangaea, surrounded by one ocean, Panthalassa, and that they drifted apart. Matching coastlines, rocks, fossils, glacier deposits and placer gold supported him, but he could not explain the force. Mapping the ocean floor showed ridges, plains and trenches; Harry Hess then proposed sea-floor spreading: new crust forms at mid-ocean ridges and old crust sinks at trenches. This led to plate tectonics: the lithosphere is broken into rigid plates that move on the soft asthenosphere and meet at divergent, convergent and transform boundaries. The Indian plate broke away from the south, moved north, and collided with Asia to raise the Himalayas.